Functional and Molecular Characterization of Hyposensitive Underactive Bladder Tissue and Urine in Streptozotocin-Induced Diabetic Rat

Background

The functional and molecular alterations of nerve growth factor (NGF) and Prostaglandin E2 (PGE2) and its receptors were studied in bladder and urine in streptozotocin (STZ)-induced diabetic rats.

Methodology/Principal Findings

Diabetes mellitus was induced with a single dose of 45 mg/kg STZ Intraperitoneally (i.p) in female Sprague-Dawley rats. Continuous cystometrogram were performed on control rats and STZ treated rats at week 4 or 12 under urethane anesthesia. Bladder was then harvested for histology, expression of EP receptors and NGF by western blotting, PGE2 levels by ELISA, and detection of apoptosis by TUNEL staining. In addition, 4-hr urine was collected from all groups for urine levels of PGE2, and NGF assay. DM induced progressive increase of bladder weight, urine production, intercontraction interval (ICI) and residual urine in a time dependent fashion. Upregulation of Prostaglandin E receptor (EP)1 and EP3 receptors and downregulation of NGF expression, increase in urine NGF and decrease levels of urine PGE2 at week 12 was observed. The decrease in ICI by intravesical instillation of PGE2 was by 51% in control rats and 31.4% in DM group at week 12.

Conclusions/Significance

DM induced hyposensitive underactive bladder which is characterized by increased inflammatory reaction, apoptosis, urine NGF levels, upregulation of EP1 and EP3 receptors and decreased bladder NGF and urine PGE2. The data suggest that EP3 receptor are potential targets in the treatment of diabetes induced underactive bladder.     

Effect of silymarin on bladder overactivity in cyclophosphamide-induced cystitis rat model

The purpose of this study was to investigate the effects of silymarin, a phytotherapeutic agent, on bladder overactivity in a cyclophosphamide (CYP)-induced cystitis rat model. Female Wistar Albino rats received a single intraperitoneal injection of CYP (150 mg/kg) or saline and after 72 h, bladder function was evaluated by in vitro preparations of whole bladders and cystometry with continuous saline infusion under urethane anesthesia. Silymarin or a vehicle was orally given for 7 days in rats. CYP was injected on the 5th day of silymarin or vehicle treatment and then the animals were killed on the 8th day. CYP-treatment dramatically potentiated the basal spontaneous contractions of isolated whole bladders compared to control rats. In anesthetized rats, during continuous infusion cystometry, intercontraction interval (ICI) was significantly shorter, but bladder voiding pressure was not significantly changed in CYP-injected rats compared to control rats. In the CYP-injected group, silymarin treatment significantly decreased the amplitude, frequency (contractions/min) and area under the curve of spontaneous contractions, but failed to change carbachol-induced contraction in isolated whole bladder. Also, silymarin treatment significantly increased the ICI in comparison to the vehicle treatment. In the saline-injected group, no significant changes in the bladder function were observed between the silymarin and vehicle-treated groups. Histopathological examination showed that CYP-induced bladder inflammation tended to be lower in the silymarin+CYP-treated group. In conclusion, the oral administration of silymarin suppressed CYP-induced bladder overactivity. Silymarin may be considered as an attractive treatment for CYP-induced bladder overactivity.     

Temporal diabetes- and diuresis-induced remodeling of the urinary bladder in the rat

The natural history of diabetes mellitus-induced remodeling of the urinary bladder is poorly understood. In this study, we examined temporal remodeling of the bladder in diabetic and diuretic rats. Male Sprague-Dawley rats were divided into three groups: streptozotocin-induced diabetic, 5% sucrose-induced diuretic, and age-matched control. Micturition and morphometric characteristics were evaluated using metabolic cages and light-microscopic examination of the bladder 4 days and 1, 2, 3, and 9 wk after induction. Digital image analysis was used to quantify equatorial cross-sectional areas of bladder tissue and lumen, as well as relative content of the three primary tissue components: smooth muscle, urothelium, and collagen. Diabetes and diuresis caused significant increases in fluid intake, urine output, and bladder weight. In both groups, progressive increases were observed in lumen area from 4 days to 3 wk after induction and in wall area from 2 to 3 wk after induction. Wall thickness decreased within the first 2 wk in the diabetic and diuretic rats but returned to control at 3 and 9 wk. As a percentage of total cross-sectional area, smooth muscle area increased, urothelium area was unchanged, and collagen area decreased in diabetic and diuretic rats after 2-3 wk compared with control rats. In conclusion, diabetes and diuresis induced similar bladder remodeling. Diabetes-induced diuresis caused adaptive physical changes in rat bladder by 4 days after induction; remodeling was observed by 2-3 wk after induction and remained stable from 3 to 9 wk.     

6-Keto-prostaglandin F1 alpha is not added to urine during passage through the rat urinary bladder in vivo

Studies were conducted to determine whether prostaglandins are added to the urine during its passage through the rat urinary bladder in vivo. Control rats and rats with chronic streptozotocin-induced diabetes were anesthetized with Inactin, 100 mg/kg i.p., and urine was collected simultaneously from both kidneys. Urine from the left kidney was collected directly from the renal pelvis via a ureteral cannula, while urine from the right kidney was collected via a cannula in the urinary bladder. Prostaglandins in the urine were measured by radioimmunoassay. No difference in urinary concentration or rate of excretion of 6-keto-PGF1 alpha or PGE2 was seen between ureteral urine and bladder urine from either normal or diabetic rats. The results of this study indicate that in vivo there is no intralumenal addition of either 6-keto-PGF1 alpha or PGE2 to the urine by the ureteral bladder of rats.     

Temporal relationships of the anti-inflammatory effect of etodolac in the adjuvant arthritic rat

Using the curative model of adjuvant arthritis, adult male Sprague-Dawley rats were treated with vehicle or etodolac (1, 3, and 8 mg/kg/day, po) for 9 days. Rats were sacrificed after 1, 2, 4, or 9 daily doses, and paw volume, PGE2 concentrations, and N-acetyl-beta-D-glucosaminidase (NAG) activity were determined in the left adjuvant-injected hindpaws. All three doses of etodolac caused a significant decrease in PGE2 concentrations after the first dose, and the decreases persisted for 2, 4, and 9 days of treatment, respectively. In rats given four daily doses of 3 and 8 mg/kg/day of etodolac, the paw volume was significantly decreased by about 50%, compared with that of the arthritic controls. A significant decrease in NAG activity was observed only after nine daily doses of 8 mg/kg/day etodolac. The sequence of anti-inflammatory events manifested following etodolac treatment would appear to be an initial inhibition of PGE2 synthesis, followed by resorption of fluid, and then by a reduction in macrophage infiltration.     

Low-dose Tadenan protects the rabbit bladder from bilateral ischemia/reperfusion-induced contractile dysfunction

Recent studies indicate that focal ischemia/reperfusion (I/R) can cause the contractile dysfunctions induced in animal models of partial bladder outlet obstruction. Tadenan (Pygeum africanum) pretreatment can prevent the rabbit bladder from developing the contractile and biochemical dysfunctions induced by partial outlet obstruction, possibly by protecting the bladder from ischemic injury. The current study was designed to determine whether pre-treating rabbits with a clinically relevant dose of Tadenan could prevent the bladder from developing the contractile dysfunctions that are induced by bilateral ischemia followed by reperfusion. New Zealand White rabbits were separated into two groups. One group was pre-treated by oral gavage for 3 weeks with Tadenan (3.0 mg/kg body wt./day). The second group was treated with vehicle (peanut oil). Five rabbits from each group were subjected to either bilateral ischemia for 1 or 3 h and than reperfused for either 1 h or 1 week. Five rabbits from each group were subjected to sham surgery and run with each of the experimental groups. The results of the current study show that Tadenan pre-treatment at the clinically relevant dose of 3.0 mg/kg body wt./day protected the bladder from the contractile dysfunctions induced by bilateral ischemia followed by reperfusion. These data are consistent with the assertion that Tadenan therapy in both rabbits and humans acts by protecting the bladder smooth muscle against cellular damage caused by ischemia and reperfusion.     

Protective effect of aminoguanidine against oxidative stress and bladder injury in cyclophosphamide‐induced hemorrhagic cystitis in rat

Cyclophosphamide (CP) is an antineoplastic agent that is used for the treatment of many neoplastic diseases. Hemorrhagic cystitis (HC) is a major dose limiting side effect of CP. Recent studies show that aminogaunidine, an inhibitor of inducible nitric oxide synthase is a potent antioxidant and prevents changes caused by oxidative stress such as depletion of antioxidant activity and tissue injury. The purpose of the study is to investigate the effect of aminoguanidine on parameters of oxidative stress, antioxidant enzymes and bladder injury caused by CP. Adult male rats were randomly divided into four groups. Control rats were administered saline; the AG control group received 200 mg/kg body wt of aminoguanidine; The CP group received a single injection of CP at the dose of 150 mg/kg body wt intraperitoneally. The CP + AG group received aminoguanidine (200 mg/kg body wt) intraperitoneally 1 h before the administration of CP. The rats were sacrificed 16 h after CP/saline administration. The bladder was used for light microscopic studies and biochemical studies. The markers of oxidative damage including protein carbonyl content, protein thiol, malondialdehyde and conjugated dienes were assayed in the homogenates along with the activities of the antioxidant enzymes, superoxide dismutase, glutathione peroxidase, catalase, and glutathione reductase and glutathione S transferase. In the bladders of CP treated rats edema of lamina propria with epithelial and sub‐epithelial hemorrhage was seen. All the parameters of oxidative stress that were studied were significantly elevated in the bladders of CP treated rats. The activities of the antioxidant enzymes were significantly lowered in the bladders of CP treated rats. Aminoguanidine pretreatment prevented CP‐induced oxidative stress, decrease in the activities of anti‐oxidant enzymes and reduced bladder damage. The results of the present study suggest the antioxidant role for aminoguanidine in CP‐induced bladder damage. Copyright © 2008 John Wiley & Sons, Ltd.     

Effects of infusion of some prostaglandins in essential fatty acid-deficient and normal rats

Infusion of 1 mg/kg per day of prostaglandin E(1) (PGE(1)) for 2 and 7 wk failed to correct the dermal signs of essential fatty acid (EFA) deficiency in rats despite the known conversion of EFA to certain prostaglandins. PGE(1) caused no significant changes in serum cholesterol, triglycerides, or phospholipids or in liver neutral lipids in EFA-deficient or normal rats. In normal rats epinephrine-induced lipolysis was greater in fat pads from infused than from untreated rats. The effect on epinephrine-induced lipolysis was greater after the 7 wk infusion than after the 2 wk infusion. The 7 wk infusion also lowered plasma free fatty acid (FFA) concentrations. Infusion of PGE(2) and PGF(2alpha) in combination for 4 wk had no significant effect on either dermal signs of EFA deficiency, lipolysis, or plasma FFA concentrations.     

Prostacyclin (PGI2) effects on anterior pituitary hormones in the rat in vivo.

Intravenous injection of 600 microgram PGE2 or PGI2 significantly increased serum LH and prolactin levels in estradiol treated ovariectomized rats. There was no effect on serum FSH concentration. PGE2 and PGI2 stimulated LH release in a non-dose dependent manner, while prolactin levels were positively correlated with the dose administered following PGI2 treatment. 6-keto-PGF1 alpha at a comparable dose had no effect on pituitary hormone levels. Subcutaneous administration of 1 mg/kg or 60 mg/kg PGI2 for seven days significantly depressed serum LH level both in male and female rats. These doses had no effect on serum FSH or prolactin levels.     

Prostaglandins as mediators of acidification in the urinary bladder of Bufo marinus

Experiments were performed to determine whether prostaglandins (PG) play a role in H+ and NH4+ excretion in the urinary bladder of Bufo marinus. Ten paired hemibladders from normal toads were mounted in chambers. One was control and the other hemibladder received PGE2 in the serosal medium (10(-5) M). H+ excretion was measured by change in pH in the mucosal fluid and reported in units of nmol (100 mg tissue)-1 (min)-1. NH4+ excretion was measured colorimetrically and reported in the same units. The control group H+ excretion was 8.4 +/- 1.67, while the experimental group was 16.3 +/- 2.64 (P less than 0.01). The NH4+ excretion in the experimental and control group was not significantly different. Bladders from toads in a 48-hr NH4+Cl acidosis (metabolic) did not demonstrate this response to PGE2 (P greater than 0.30). Toads were put in metabolic acidosis by gavaging with 10 ml of 120 mM NH4+Cl 3 x day for 2 days. In another experiment, we measured levels of PG in bladders from control (N) and animals placed in metabolic acidosis (MA). Bladders were removed from the respective toad, homogenized, extracted, and PG separated using high-pressure liquid chromatography and quantified against PG standards. The results are reported in ng (mg tissue)-1. PGE2 fraction in N was 1.09 +/- 0.14 and in MA was 3.21 +/- 0.63 (P less than 0.01). PGF1 alpha, F2 alpha and I2 were not significantly different in N and MA toads. Bladders were also removed from N and MA toads, and incubated in Ringer's solution containing [3H]arachidonic acid (0.2 microCi/ml) at 25 degrees C for 2 hr. Bladders were then extracted for PG and the extracts separated by thin layer chromatography. PG were identified using standards and autoradiography, scraped from plates, and counted in a scintillation detector. The results are reported in cpm/mg tissue x hr +/- SEM. In MA toads, PG6-keto-F1 alpha = 1964 +/- 342, PGF2 alpha = 1016 +/- 228, and PGE2 = 904 +/- 188; in N animals PG6-keto-F1 alpha = 625 +/- 280, PGF2 alpha = 364 +/- 85, and PGE2 = 404 +/- 104; (P less than 0.01, less than 0.025, less than 0.05, respectively). We conclude that PGE2 may be an important mediator of H+ excretion in toad urinary bladder and that endogenous PGE2 levels are increased in response to MA.     

Influence of the position of the side chain hydroxy group on the gastric antisecretory and antiulcer actions of E1 prostaglandin analogs.

The influence of transposing the C-15 hydroxy group of prostaglandin E1 methyl ester (PGE2ME) on gastric antisecretory and antiulcer actions was investigated. The compound (+/-)15-deoxy- 16alpha, beta-hydroxy PGE1ME (SC-28904) was equipotent to the reference standard PGE1ME in suppressing histamine-stimulated gastric secretion in the Heidenhain pouch (HP) dog. In contrast to PGE1ME, SC-28904 was longer acting when administered intravenously and also showed significant oral activity in the histamine-stimulated gastric fistula dog. SC-28904 was also equipotent to PGE1ME (range of active doses of 0.5 to 5.0 mg/kg, s.c.) in inhibiting forced-exertion gastric ulceration in rats. The compound (+/-)15-deocy-17alpha, beta-hydroxy PGE1ME (SC-30963) was an inactive antisecretory agent in the dog at the 1.0 mg/kg i.v. bolus dose. This dose was 100 times greater than the active antisecretory dose of PGE1ME. Likewise, SC-30693, when administered subcutaneously at a 5.0 mg/kg dose, was also totally inactive in preventing gastric ulcers induced by forced exertion in rats. The important implications of this work are that some of the receptor sites for the PGE1 molecule could easily accomodate the side chain hydroxy group either in the C-15 or C-16 position. Moreover, the hydroxy group in the latter position significantly improved the biological activity of PGE1ME.     

Effects of L-arginine and L-NAME on chronic partial bladder outlet obstruction in rabbit

Nitric oxide (NO) is synthesized from L-arginine by nitric oxide synthase (NOS). NOS can be inhibited by NG-nitro-L-arginine methyl ester (L-NAME) and stimulated by supplementing the diet with L-arginine. The aim of this study was to investigate the influence of NOS activity on the response of rabbits to chronic partial bladder outlet obstruction (PBOO). Surgical PBOOs (2 and 8 wk) were performed on male New Zealand White rabbits. Before obstruction, one-third of the animals were premedicated for 7 days with L-NAME and another third with L-arginine. The results are summarized as follows. First, bladder weight after 8-wk PBOO was significantly lower in animals treated with L-arginine compared with both untreated and rabbits treated with L-NAME. Second, contractile function decreased progressively with PBOO duration. However, after 8 wk of PBOO, the L-arginine group had significantly greater contractile function compared with the no-treatment group, and the L-NAME group had significantly lower contractile function compared with the no-treatment group. Third, at 8 wk following PBOO, the level of protein oxidation and nitration was lowest for the L-arginine group and highest in the L-NAME group. These studies clearly demonstrated that increasing blood flow by stimulating NOS significantly protected the bladder from PBOO dysfunctions, whereas inhibiting blood flow by L-NAME enhanced the dysfunctions mediated by PBOO.     

Cardioprotective Effect of Selenium Against Cyclophosphamide-Induced Cardiotoxicity in Rats

The objective of this study is to evaluate the possible protective effects of selenium (Se) against cyclophosphamide (CP)-induced acute cardiotoxicity in rats. A total of 42 male Spraque-Dawley rats were divided into six groups (n = 7). Rats in the first group were served as control. Rats in the second group received CP (150 mg/kg) at the sixth day of experiment. Animals in the third and fourth groups were treated with only 0.5 and 1 mg/kg Se respectively for six consecutive days. Rats in the fifth and sixth groups received respective Se doses (0.5 or 1 mg/kg) for 6 days and then a single dose of CP administered on the sixth day. On day 7, the animals were sacrificed; blood samples were collected to measure malondialdehyde (MDA), glutathione (GSH), lactate dehydrogenase (LDH), creatine kinase-MB (CK-MB), and ischemia-modified albumin (IMA) levels. Heart tissues were processed routinely and tissue sections were stained with H + E for light microscopic examination. In the CP-treated rats MDA, LDH, CK-MB, and IMA serum levels increased, while GSH levels decreased. Microscopic evaluation showed that tissue damage was conspicuously lower in CP plus Se groups. Moreover, 1 mg/kg Se was more protective than 0.5 mg/kg Se as indicated by histopathological and biochemical values. In conclusion, Se is suggested to be a potential candidate to ameliorate CP-induced cardiotoxicity which may be related to its antioxidant activity.     

Bladder dysfunction after acute urinary retention in the rats: a novel over active bladder model

As there is increasing evidence that benign prostatic hyperplasia and its related acute urinary retention (AUR) induce over active bladder (OAB) syndrome, we investigated the effects of AUR on bladder function over a 4-week period in a rat model. Ten-week-old female Sprague-Dawley rats were used in this study. AUR was induced by clamping the distal urethra of each rat with a small clip, and then infusing 3 ml (0.6 ml/min) of saline with an infusion pump through a transurethral catheter (22G). The obstruction was sustained for 60 min and the clip was removed and then the bladder was allowed to drain through the catheter. The bladder function was estimated by voiding behavior studies (at 3 days, 1, 2, 3, and 4 weeks), cystometric studies (at 2 and 4 weeks) and organ bath studies using KCl and carbachol (at 2 and 4 weeks). Furthermore, we evaluated histological changes in the rat bladder 2 and 4 weeks after the induction of AUR. The same parameters were also measured in non-AUR rats (control group). The rat bladder weight in the AUR group at 2 weeks was significantly larger than that of the controls, and returned to the control level 4 weeks after the AUR episode. The voiding behavior studies showed significant increase in micturition frequency per day and decrease in single voiding volume 3 days after the induction of AUR, and this voiding behavior was continued for more than 2 weeks. The cystometric studies showed a significant decrease in single-voided volume at 2 weeks rat. However, no significant changes of the other parameters were observed in the rats. The histological studies showed significant infiltration of neutrophils and lymphocytes, as well as increase in turnover of epithelium in AUR rats at 2 weeks, while significant increases in fibrosis in submucosal layer were observed in AUR rats at 4 weeks. This study demonstrated that bladder dysfunction in the rat model caused by AUR needs more than 2 weeks of recovery period. The AUR-associated alterations in the bladder may represent a key clue to understand the underlying pathophysiological mechanisms, which take place in OAB syndrome.     

Acetaminophen at Different Doses Protects Brain Microsomal Ca2+-ATPase and the Antioxidant Redox System in Rats

Acetaminophen, an analgesic and antipyretic drug, rescues neuronal cells from mitochondrial redox impairment and reactive oxygen species (ROS). Excessive administration of acetaminophen above the recommended daily dose range has some negative effects on the brain. We investigated the effects of different doses of acetaminophen on Ca²⁺-ATPase and the antioxidant redox system in rats. Seventy rats were randomly divided into seven equal groups. The first was used for the control. One dose of 5, 10, 20, 100, 200, and 500 mg/kg acetaminophen was intraperitoneally administered to rats constituting the second, third, fourth, fifth, sixth, and seventh groups, respectively. After 24 h, brain cortical samples were taken and brain microsomal samples were obtained by ultracentrifugation. Brain and microsomal lipid peroxidation (LP) and brain calcium levels in the sixth and seventh groups were increased compared to control. LP levels in the second, third, and forth groups; brain vitamin E levels; brain and microsomal glutathione peroxidase (GSH-Px); and Ca²⁺-ATPase activity in the sixth and seventh groups were lower than in control, although brain vitamin E concentrations in the second, third, fourth, and fifth groups and microsomal GSH-Px activity in the third and fourth groups were higher than in control. Brain cortical β-carotene and vitamin A concentrations did not differ in the seven groups. In conclusion, 5–100 mg/kg acetaminophen seems to have protective effects on oxidative stress-induced brain toxicity by inhibiting free radicals and supporting the antioxidant redox system.     

Effects of poly(ADP-ribose) polymerase inhibition in bladder damage caused by cyclophosphamide in rats

It was previously shown that nitric oxide produced by inducible nitric oxide synthase (iNOS) and peroxynitrite are responsible for cyclophosphamide (CP)-induced cystitis. Since endogenous production of peroxynitrite is known to lead to poly(ADP-ribose) polymerase (PARP) activation, in this study, the aim was to evaluate whether the PARP activation pathway is also included in the pathogenesis of CP-induced bladder ulceration in rats. A total of 48 male albino Wistar rats were divided into 5 groups. Group 1 served as control and was given 2 ml saline; four groups received a single dose of CP (200 mg/kg) with the same time intervals. Group 2 received CP only; Group 3, selective iNOS inhibitor 1400W (20 mg/kg); Group 4, peroxynitrite scavenger ebselen (30 mg/kg); and Group 5, PARP inhibitor 3-aminobenzamide (20 mg/kg). CP injection resulted in severe cystitis with continuous macroscopic hemorrhage, strong edema, inflammation, and ulceration. Moreover, bladder iNOS activation and urine nitrite-nitrate levels were dramatically increased. Histologically, 1400W protected bladder against CP damage and decreased urine nitrite-nitrate levels and bladder iNOS induction. Ebselen has shown similar histologic results with 1400W without changing urinary nitrite-nitrate level and iNOS activity. Furthermore in the 3-aminobenzamide group, beneficial effects had also occurred including decreased ulceration. These results suggest that PARP activation involves pathogenesis of CP-induced bladder ulceration. Furthermore, PARP is not only important for ulceration but also for bladder edema, hemorrhage, and inflammation because of broken uroepithelial cellular integrity.     

On the role of serotonin2A/2C receptors in the sensitization to cocaine.

Apart from showing involvement of dopamine, recent studies also indicate a role of serotonin (5-HT) in the behavioral effects of cocaine in rodents. In the present study we investigated the role of 5-HT2A/2C receptors in the development or expression of sensitization to cocaine in rats, using ketanserin, an antagonist at these receptors. Since ketanserin also shows a high affinity for alpha1-adrenoceptors, prazosin, a comparative antagonist at those receptors was also examined. Male Wistar rats were treated repeatedly (for 5 days) with cocaine (10 mg/kg) in combination with either vehicle, or ketanserin (1-3 mg/kg) or prazosin (3 mg/kg); afterwards, on day 10, they received a challenge dose of cocaine (10 mg/kg). In another experiment, the animals were given either with vehicle or cocaine (10 mg/kg) for 5 days, and were then challenged with cocaine (10 mg/kg) in combination with vehicle, or ketanserin (1-3 mg/kg) or prazosin (3 mg/kg) on day 10. Acute administration of cocaine increased the locomotor activity in rats; that hyperactivation was inhibited by ketanserin (3 mg/kg), but not by prazosin. In animals treated repeatedly with cocaine, the locomotor hyperactivity induced by a challenge dose of the psychostimulant was ca. 2-3 times higher than that after its first administration. No difference was observed in the response to cocaine challenge in rats treated repeatedly with cocaine, ketanserin+cocaine, or prazosin+cocaine. In animals treated repeatedly with the psychostimulant, the behavioral response to a challenge dose of cocaine was dose-dependently decreased when the drug was combined with ketanserin, but not with prazosin. The above findings indicate a role of 5-HT2A/2C receptors (but not alpha1-adrenoceptors) in the acute locomotor hyperactivity, as well as in the expression (but not development) of cocaine sensitization. Since chronic use of cocaine by humans may lead to psychoses or craving for this drug of abuse, our findings also seem to indicate possible importance of 5-HT2A/2C receptor antagonists in the therapy of cocaine addiction.     

Intrauterine infusion of prostaglandin E2 and subsequent luteal function in cattle.

The objective was to evaluate the effect of intrauterine infusion of prostaglandin E2 (PGE2) on luteal function in cattle. Heifers and cows were randomly assigned after two normal estrous cycles to either PGE2 or control treatment groups. Females in Treatment A were infused with 1 mg of PGE2 once daily into the uterine horn ipsilateral to the corpus luteum between days 7-10 of the estrous cycle with a 0.25 ml plastic semen straw and an artificial insemination pipette. Females in Treatment B were similarly infused with 1 mg of PGE2 once daily in 20 ml of a carrier vehicle via a catheter on days 10 and 11 of the estrous cycle. Control animals were infused with the carrier vehicle using either a semen straw (Treatment C) or via a catheter (Treatment D) on the same days of the estrous cycle. Blood samples were collected daily to monitor plasma progesterone concentrations during the treatment period. Females infused with PGE2 on days 7-10 of the estrous cycle returned to estrus in a mean of 23.5 days (range 22-25 days) and were similar (P > 0.05) to those infused on days 10 and 11 which returned to estrus in 23.5 days (range 22-25 days). Animals similarly infused with carrier vehicle on the same days of the estrous cycle returned to standing estrus in 20.2 days (range 17-23 days). Plasma progesterone concentrations indicated an extended period of elevated progesterone concentrations in PGE2-treated animals compared with control animals. These results indicate that short term administration of PGE2 early in the estrous cycle may result in extended luteal maintenance.     

Alpha-tocopherol, beta-carotene and melatonin administration protects cyclophosphamide-induced oxidative damage to bladder tissue in rats

Cyclophosphamide (CP) has potential urotoxicity such as hemorrhagic cystitis (HC). 2-Mercaptoethane sulfonate (mesna) has been widely used as an effective agent against CP-induced cystitis, but significant HC has still been encountered clinically. In recent studies, mesna was shown to be more effective if combined with antioxidants. The purpose of this study was to evaluate the effects of antioxidants, alpha-tocopherol, beta-carotene and melatonin on CP-induced bladder damage in rats, even if used without mesna administration. Male Sprague-Dawley rats weighing 180-210 g were divided into 5 groups. Four groups received a single dose of CP (100 mg/kg) intraperitoneally with the same time intervals. Group 2 received CP only, group 3 received beta-carotene (40 mg/kg/day), group 4 received alpha-tocopherol (40 mg/kg/day) and group 5 received melatonin (10 mg/kg/day) both before and the day after CP injection. Group 1 served as control. Bladder histopathology, as well as malondialdehyde (MDA) and iNOS levels, and excretion of nitrite-nitrates (NO(x)) in urine were evaluated. CP injection resulted in severe histological changes and macroscopic hematuria. alpha-Tocopherol and melatonin showed meaningful protection against bladder damage. Protection by beta-carotene was also significant but weaker. MDA levels increased significantly with CP injection and all antioxidants ameliorated this increase in bladder tissue. CP also elevated the NO(x) level in urine and iNOS activity in bladder. Only melatonin was able to decrease these parameters. In conclusion, there is no doubt that oxidants have a role in the pathogenesis of CP-cystitis. Antioxidants, especially melatonin and alpha-tocopherol, may help to ameliorate bladder damage induced by CP.