Effects of hCG on reduced numbers of hCG receptors in the prefrontal cortex and cerebellum of rat models of Alzheimer’s disease

ABSTRACT

Age-associated changes in the levels of luteinizing hormone and human chorionic gonadotropin (hCG) are potential risk factors for Alzheimer’s disease (AD); hCG concentration is related to the incidence of AD. The highest density of hCG receptors is in zones of the brain that are vulnerable to AD and streptozotocin (STZ) can decrease the density of this receptor. We investigated the effects of different doses of hCG on hCG receptor density in the prefrontal cortex and cerebellum in a rat model of STZ-induced AD. AD was induced by intracerebroventricular injection of 3 mg/kg STZ. The resulting AD rats were treated for 3 days with 50, 100 or 200 IU/200 μl hCG, or with saline as a control. Sections of prefrontal cortex and cerebellum were stained immunohistochemically and hCG receptor-immunoreactive (ir) neurons were counted. STZ injected into the lateral ventricles of rat brains reduced the density of hCG receptor-ir neurons in the prefrontal cortex and cerebellum. hCG administration resulted in a significant dose-dependent increase in the number of hCG receptor-ir neurons in the prefrontal cortex and cerebellum. The maximum increase in the number of receptors occurred following the 200 IU dose of hCG. Administration of hCG ameliorated the lowered density of hCG receptor-ir neurons in the cerebellum and prefrontal cortex in STZ-induced AD rats.     

Protective effects of the volatile oil of Nigella sativa seeds on β-cell damage in streptozotocin-induced diabetic rats: a light and electron microscopic study

The aim of this study was to evaluate the possible protective effects of the volatile oil of Nigella sativa (NS) seeds on insulin immunoreactivity and ultrastructural changes of pancreatic β-cells in STZ-induced diabetic rats. STZ was injected intraperitoneally at a single dose of 50 mg/kg to induce diabetes. The rats in NS treated groups were given NS (0.2 ml/kg) once a day orally for 4 weeks starting 3 days prior to STZ injection. To date, no ultrastructural changes of pancreatic β-cells in STZ induced diabetic rats by NS treatment have been reported. Islet cell degeneration and weak insulin immunohistochemical staining was observed in rats with STZ-induced diabetes. Increased intensity of staining for insulin, and preservation of β-cell numbers were apparent in the NS-treated diabetic rats. The protective effect of NS on STZ-diabetic rats was evident by a moderate increase in the lowered secretory vesicles with granules and also slight destruction with loss of cristae within the mitochondria of β-cell when compared to control rats. These findings suggest that NS treatment exerts a therapeutic protective effect in diabetes by decreasing morphological changes and preserving pancreatic β-cell integrity. Consequently, NS may be clinically useful for protecting β-cells against oxidative stress.     

Clinical and anti-aging effect of mud-bathing therapy for patients with fibromyalgia

This study focuses on two inflammatory diseases, viz., “diabetes mellitus (DM)” that causes serious complications such as retinopathy, nephropathy, and neuropathy, and “ischemic colitis” which is evoked by DM. Ischemic colitis originates from the reduction in mesenteric blood flow to the colon with existence of the occlusive or non-occlusive reasons. Our study objective was to provide early diagnostic approach for ischemic colitis in streptozotocin (STZ)-induced diabetic rats. Sprague-Dawley rats were divided into four groups: (i) control use of 0.1 M citrate buffer, the solvent of streptozotocin (C), (ii). induced ischemia (I), (iii) rats subjected to 60 mg/kg STZ intraperitoneally to induce type 1 diabetes (D) (48 h after STZ injection, blood glucose levels >200 mg/dl were considered as diabetic), and (iv) diabetic rats subjected to intestinal ischemia (D+I). The third diabetic group (D) was not operated. At the end of the experimental period, rats were sacrificed, C-reactive protein (CRP) and calprotectin levels were measured in the serum and colon tissue specimens. Tissue specimens were also analyzed histologically. We found that serum and colon calprotectin levels were elevated in the D+I group compared to the D and/or I group alone, but relatively calprotectin levels increased in I as compared to C group in colon tissues. CRP levels were significantly increased with ischemic colitis in diabetes, while colon CRP levels were decreased. These results provide evidence for the existence of inflammation in the STZ-induced diabetic rats with ischemic colitis. In conclusion, our measurements of serum calprotectin levels of STZ-induced diabetic rats with ischemic colitis provide a practical approach for an early diagnosis of ischemic colitis. Furthermore, these biochemical analyses correlate well with the histopathologic findings of STZ-induced diabetic rats with ischemic colitis. Future studies would be desirable to further strengthen the role of calprotectin in the early diagnosis of ischemic colitis in diabetics clinical settings.     

Protective effects of luteolin on rat testis following exposure to 900 MHz electromagnetic field

Increasing cell phone use calls for clarification of the consequences of long term exposure to electromagnetic fields (EMF). We investigated the effects of EMF on the testes of 12-week-old rats as well as possible protective effects of luteolin on testis tissue. Twenty-four Wistar albino rats were randomly divided into four groups: control, EMF, luteolin, and EMF + luteolin. The number of Leydig cells, primary spermatocytes and spermatids were reduced in the EMF group compared to the control group. In the EMF + luteolin group, the number of Leydig cells, primary spermatocytes and spermatids was significantly greater than the EMF group. We found an increase in superoxide dismutase (SOD) activity in the EMF group compared to the control group. In the EMF group, we found decreased wet weight of testes and serum testosterone levels compared to the control group. Decreased SOD enzyme activity, and increased serum testosterone levels and weight of the testes were observed in the EMF + luteolin group compared to the EMF group. EMF also affected sperm morphology. We found that in rat testis repeated exposure to 900 MHz EMF caused changes in testicular tissue and that the antioxidant, luteolin, substantially reduced the deleterious effects of EMF.     

Effects of 5‐HT1 and 5‐HT 2 Receptor Agonists on Electromagnetic Field‐Induced Analgesia in Rats

Much evidence demonstrates the antinociceptive effect of magnetic fields (MFs). However, the analgesic action mechanism of the electromagnetic field (EMF) is not exactly understood. The aim of the present study was to investigate the effects of 5‐HT₁ and 5‐HT₂ receptor agonists (serotonin HCl and 2,5‐dimethoxy‐4‐iodoamphetamine [DOI] hydrochloride) on EMF‐induced analgesia. In total, 66 adult male Wistar albino rats with an average body mass of 225 ± 13 g were used in this study. The animals were subjected to repeated exposures of alternating 50 Hz and 5 mT EMF for 2 h a day for 15 days. Prior to analgesia tests, serotonin HCl (5‐HT₁ agonist) 4 mg/kg, WAY 100635 (5‐HT₁ antagonist) 0.04 mg/kg, DOI hydrochloride (5‐HT₂ receptor agonist) 4 mg/kg, and SB 204741 (5‐HT₂ antagonist) 0.5 mg/kg doses were injected into rats. For statistical analysis of the data, analysis of variance was used and multiple comparisons were determined by Tukey’s test. Administration of serotonin HCl MF (5 mT)‐exposed rats produced a significant increase in percent maximal possible effect (% MPE) as compared with EMF group (P < 0.05). On the contrary, injection of WAY 100635 to MF‐exposed rats produced a significant decrease in analgesic activity (P < 0.05). Similarly, the administration of DOI hydrochloride significantly increased % MPE values as compared with the EMF group while SB 204741 reduced it (P < 0.05). In conclusion, our results suggested that serotonin 5‐HT₁ and 5‐HT₂ receptors play an important role in EMF‐induced analgesia; however, further research studies are necessary to understand the mechanism. Bioelectromagnetics. 2019;40:319–330. © 2019 Bioelectromagnetics Society.     

Effects of exposure to electromagnetic field from mobile phone on serum hepcidin and iron status in male albino rats

Background: Electromagnetic fields (EMF) created by mobile phones during communication have harmful effects on different organs.

Objectives: To explore the effects of exposure to EMF of mobile phones for different durations on hematological parameters and serum hepcidin in male albino rats.

Methods: Three groups of eight rats: Sham group: rats were exposed to a mobile phone while it was switched off, Experimental group I: rats were exposed to microwave radiation from a mobile phone at 9 am for 30 min. Experimental group II: rats were exposed to microwave radiations from a mobile phone at 9 am for an hour. In all groups, the exposure was conducted daily for a total period of 5 months, followed by estimation of serum hepcidin, total leukocyte count (TLC), interleukin 6 (IL6), serum iron, serum ferritin, plasma hemoglobin (Hb), hematocrit value (Hct), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), unsaturated iron binding capacity (UIBC), total iron binding capacity (TIBC) and 1.25 dihydroxycholecalciferol levels.

Results: In Experimental group II, there was a significant increase in serum hepcidin, TLC, IL6 and serum ferritin; however, serum iron, TIBC, UIBC, 1.25 dihydroxycholecalciferol, plasma Hb, Hct, MCV and MCH were significantly lower in comparison to sham-exposed group. In Experimental group I, there was a significant increase in serum hepcidin, IL6 and TLC, along with non-significant changes in the remaining studied parameters in comparison to the sham-exposed group. Conclusion: Chronic exposure to EMF from mobile phones increases hepcidin level with subsequent impairment of iron parameters, in addition to negatively affecting both UIBC and TIBC.     

The renoprotective effects of berberine via the EP4-Gαs-cAMP signaling pathway in different stages of diabetes in rats

Abstract

Aims: To investigate the renoprotective roles of berberine (BBR) in different stages of diabetic nephropathy (DN) in streptozotocin (STZ)-induced diabetic rats fed a high-sugar and high-fat diet. Methods: Diabetes was induced in mice by intraperitoneal injection of STZ, and the mice were then randomly divided into groups: normal, diabetes, high-sugar and high-fat and BBR (high, median and low dose) groups. The body weight (BW), kidney weight to body weight (KW/BW), blood urea nitrogen, urine total protein to urine creatinine ratio and serum creatinine were measured on different weeks throughout the study. The protein levels of E prostanoid receptor 4 (EP4), Gαs and content of cAMP in the kidney were, respectively, detected by western blot analysis and RIA analysis. Results: In the DN rats, there was remarkable renal damage. BBR restored renal functional parameters, suppressed alterations in histological and ultrastructural changes in the kidney tissues and increased EP4, Gαs and cAMP levels compared with those of the DN model group. In addition, BBR has different therapeutic effects during the different stages of the development of DN, and it works best in the sixth week. Conclusion: These studies demonstrate, for the first time, that BBR exerts renoprotective effects in different stages of DN via EP4- Gαs- AC-cAMP signaling pathway in STZ-induced DN rats fed a high-sugar and high-fat diet.     

Altered morphology and biochemistry of the female rat liver following 900 megahertz electromagnetic field exposure during mid to late adolescence

ABSTRACT

Despite their benefits, technological devices such as cell phones may also have deleterious effects on human health. Considerable debate continues concerning the effects of the electromagnetic field (EMF) emitted during cell phone use on human health. We investigated the effects of exposure to 900 megahertz (MHz) EMF during mid to late adolescence on the rat liver. Control (ContGr), sham (ShmGr) and EMF (EMFGr) groups of female rats were established. We exposed the EMFGr rats daily to 900 MHz EMF on postnatal days 35?59. ShmGr rats underwent sham procedures. No procedure was performed on ContGr rats. Rats were sacrificed on postnatal day 60 and the livers were extracted. One part of the liver was stained with Masson’s trichrome or hematoxylin and eosin. The remaining tissue was used to measure oxidative stress markers including malondialdehyde, glutathione, catalase, superoxide dismutase, 8-hydroxydeoxyguanosine (8-OHdG) and nitrotyrosine. Total antioxidant status and total oxidant status were used to calculate the oxidative stress index. We found normal hepatic morphology in the ContGr and ShmGr groups. The EMFGr group exhibited occasional irregularities in the radial arrangement of hepatocytes, cytoplasmic vacuolization, hemorrhage, sinusoid expansion, hepatocyte morphology and edema. Biochemical analysis revealed that 8-OHdG and SOD levels in EMFGr decreased significantly compared to the ContGr and ShmGr groups. Exposure to a continuous 900 MHz EMF for 1 h daily during mid to late adolescence may cause histopathological and biochemical alterations in hepatic tissue.     

Anthocyanins as a potential pharmacological agent to manage memory deficit,oxidative stress and alterations in ion pump activity induced by experimental sporadic dementia of Alzheimer's type

Anthocyanins (ANT) are polyphenolic flavonoids with antioxidant and neuroprotective properties. This study evaluated the effect of ANT treatment on cognitive performance and neurochemical parameters in an experimental model of sporadic dementia of Alzheimer's type (SDAT). Adult male rats were divided into four groups: control (1 ml/kg saline, once daily, by gavage), ANT (200 mg/kg, once daily, by gavage), streptozotocin (STZ, 3 mg/kg) and STZ plus ANT. STZ was administered via bilateral intracerebroventricular (ICV) injection (5 μl). ANT were administered after ICV injection for 25 days. Cognitive deficits (short-term memory and spatial memory), oxidative stress parameters, and acetylcholinesterase (AChE) and Na⁺-K⁺-ATPase activity in the cerebral cortex and hippocampus were evaluated. ANT treatment protected against the worsening of memory in STZ-induced SDAT. STZ promoted an increase in AChE and Na⁺-K⁺-ATPase total and isoform activity in both structures; ANT restored this change. STZ administration induced an increase in lipid peroxidation and decrease in the level of antioxidant enzymes, such as superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx), in the cerebral cortex; ANT significantly attenuated these effects. In the hippocampus, an increase in reactive oxygen species (ROS), nitrite and lipid peroxidation levels, and SOD activity and a decrease in CAT and GPx activity were seen after STZ injection. ANT protected against the changes in ROS and antioxidant enzyme levels. In conclusion, the present study showed that treatment with ANT attenuated memory deficits, protected against oxidative damage in the brain, and restored AChE and ion pump activity in an STZ-induced SDAT in rats.     

Effect of exposure to 50 Hz magnetic field with or without insulin on blood–brain barrier permeability in streptozotocin‐induced diabetic rats

We investigated the effect of long‐term exposure to modulation magnetic field (MF), insulin, and their combination on blood–brain barrier (BBB) permeability in a diabetic rat model. Fifty‐three rats were randomly assigned to one of six groups: sham, exposed to no MF; MF, exposed to MF; diabetes mellitus (DM), DM induced with streptozotocin (STZ); DM plus MF (DMMF); DM plus insulin therapy (DMI); and DM plus insulin therapy plus MF (DMIMF). All the rats underwent Evans blue (EB) measurement to evaluate the BBB 30 days after the beginning of experiments. The rats in MF, DMMF, and DMIMF groups were exposed to MF (B = 5 mT) for 165 min every day for 30 days. Mean arterial blood pressure (MABP), body mass, and serum glucose level of the study rats were recorded. The extravasation of brain EB of the MF, DM, DMMF, DMI, and DMIMF groups was higher than that of the sham group and the extravasation of right hemisphere of the DMIMF group was highest (P < 0.05). The post‐procedure body mass of the sham and MF groups were significantly higher than those of the DM and DMMF groups (P < 0.05). In the DM, DMMF, DMI, and DMIMF groups, the baseline glucose was significantly lower than the post‐procedure glucose (P < 0.05). DM and MF increase BBB permeability; in combination, they cause more increase in BBB permeability, and insulin decreases their effect on BBB. Improved glucose metabolism may prevent body mass loss and the hypoglycemic effect of MF. DM increases MABP but MF causes no additional effect. Bioelectromagnetics 31:262–269, 2010. © 2009 Wiley‐Liss, Inc.     

Berberine regulates the expression of E-prostanoid receptors in diabetic rats with nephropathy

Diabetic nephropathy (DN) is a major cause of morbidity and mortality in diabetic patients. Effective therapies to prevent the development of this disease and to improve advanced kidney injury are required. Berberine (BBR) has preventive effects on diabetes and its complications. This study is to investigate the effects of BBR on the expression of E-prostanoid receptors (EPs) in rats with high-fat diet and streptozotocin (STZ)-induced DN and underlying molecular mechanisms of BBR on DN rats. DN model was induced in male Sprague–Dawley rats with high-fat diet and low dose of STZ injection. BBR (50, 100, 200 mg/kg/d) were orally administered to rats after STZ injection and conducted for 8 weeks. The levels of interleukin-6 (IL-6) and prostaglandin E₂ (PGE₂) in renal cortex were measured by enzyme-linked immunosorbent assay. Expression of EPs receptors (EP1–EP4) were determined by western blotting. Remarkable renal damage, hyperglycemia and hyperlipidemia were observed in DN rats. BBR could restore renal functional parameters, suppress alterations in histological and ultrastructural changes in the kidney tissues, improve glucose and lipid metabolism disorders, and increase cAMP levels compared with those of DN model group (Wang et al. in Mol Biol Rep 40:2405–2418, 2013). The level of IL-6 and PGE₂ were significantly increased in DN model group compared with normal group, BBR could apparently reduced the level of IL-6 and PGE₂. Furthermore, the expression of EP1 and EP3 were both increased and EP4 was lessened in the DN model group compared with normal group, BBR could down-regulate total protein expression of EP1 and EP3 of renal cortex in DN rats and up-regulate the expression of EP4, and there is no significant difference on the expression of EP2 among all groups. These studies demonstrate, for the first time, that BBR exerts renoprotection in high-fat diet and STZ-induced DN rats by modulating the proteins expression of EPs in EP–G protein–cAMP signaling pathway.     

Therapeutic effect of organoselenium dietary supplementation in a sporadic dementia of Alzheimer's type model in rats

It is known that selenium (Se) might play different roles in the progression of Alzheimer's disease (AD), but there is a lack of evidence that proves whether supplementation with Se is beneficial or not for the treatment of AD. Thus, the aim of the current study was to investigate the therapeutic effect of p,p'-methoxyl-diphenyl diselenide [(MeOPhSe)₂], an organoselenium compound, against streptozotocin (STZ)-induced sporadic dementia of Alzheimer's type (SDAT) in rats. Male Wistar rats received STZ twice daily (1.0 mg/8 μl; 4 μl/ventricle) for 21 days. After 21 days of STZ injection, regular-diet-fed rats were supplemented with 10 ppm of (MeOPhSe)₂ during 30 days. At the end of this period, the rats were challenged in the Morris water maze and step-down passive avoidance tasks. The activity of acetylcholinesterase (AChE), deficit in cerebral energy metabolism (measurement of adenosine 5-triphosphate and adenosine 5-diphosphate levels), and oxidative and nitrosative stress were determined in the cortex and hippocampus of rats. The results demonstrated that (MeOPhSe)₂ dietary supplementation reverted STZ-induced memory impairment of rats in both cognitive tasks. The findings also indicated that (MeOPhSe)₂ dietary supplementation reverted oxidative stress in the STZ group (decreased reactive species and tyrosine nitration levels and enhanced nonprotein thiol levels). Moreover, (MeOPhSe)₂ dietary supplementation normalized AChE activity, which was enhanced by STZ injection, but did not revert the deficit in cerebral energy metabolism caused by STZ. The results of the present study indicated the therapeutic effect of the (MeOPhSe)₂-supplemented diet in a rat model of SDAT.     

Effects of Andrographis paniculata (Burm. F.) Extract on Diabetic Nephropathy in Rats

Background:Hyperglycemia and accumulation of advanced glycation end products (AGEs) play a significant role in the development of diabetic nephropathy. Andrographis paniculata (AP) is a plant with high flavonoid content with the potential to suppress oxidative stress activity in cells and tissue. This study was aimed to investigate the role of Andrographis paniculata extract (APE) in protecting kidney damage due to the formation of AGEs in the renal glomerulus in diabetic rats.Methods:A total of 30 male Sprague Dawley rats were randomly divided into five groups as follows: normal control group, streptozocin (STZ) induced diabetic group, STZ-induced diabetic group with AP extract (100 mg/kg BW), STZ-induced diabetic rats with AP extract (200 mg/kg BW), and STZ-induced diabetic rats with APE (400 mg/ kg BW). Blood glucose levels were measured before treatment and after treatment. Serum and urine parameters were determined. Antioxidant enzymes and lipid peroxide levels were determined in the kidney along with histopathological examination.Results:The finding of this study showed that treatment APE at the dose of 200 mg/kg and 400 mg/kg ameliorated kidney hypertrophy index. SOD, catalase, and GSH activities significantly decreased in the kidney of STZ-diabetic rats compared to the normal control rats. Treatment with APE significantly decreased malondialdehyde level at the dose of 200 and 400 mg/kg BW.Conclusion:This study revealed evidence for improving diabetic retinopathy in male rats treated with Andrographis paniculata extract. APE significantly decreased oxidative stress activities in kidney of diabetic rats.Key Words: Andrographis, Diabetic Nephropathies, Streptozocin, Rats, Oxidative Stress     

Galangin,a dietary flavonoid,improves antioxidant status and reduces hyperglycemia-mediated oxidative stress in streptozotocin-induced diabetic rats

Objective: To examine the effect of galangin on hyperglycemia-mediated oxidative stress in streptozotocin (STZ)-induced diabetic rats.

Methods: Diabetes was induced by intraperitoneal administration of low-dose STZ (40?mg/kg body weight (BW)) into male albino Wistar rats. Galangin (8?mg/kg BW) or glibenclamide (600?µg/kg BW) was given orally, once daily for 45 days to normal and STZ-induced diabetic rats.

Results: Diabetic rats showed significantly increased levels of plasma glucose, thiobarbituric acid reactive substances, lipid hydroperoxides, and conjugated dienes. The levels of insulin and non-enzymatic antioxidants (vitamin C, vitamin E, reduced glutathione) and the activity of enzymatic antioxidants (superoxide dismutase, catalase, glutathione peroxidase, and glutathione-S-transferase (GST)) were decreased significantly in diabetic control rats. These altered plasma glucose, insulin, lipid peroxidation products, enzymatic and non-enzymatic antioxidants ions were reverted to near-normal level after the administration of galangin and glibenclamide.

Conclusion: The present study shows that galangin decreased oxidative stress and increased antioxidant status in diabetic rats, which may be due to its antidiabetic and antioxidant potential.     

Hypoglycemic and hepatoprotective activity of Rosmarinus officinalis extract in diabetic rats

The present study examined the effect of water extract (200 mg/kg body weight) of Rosmarinus officinalis L. in streptozotocin (STZ)-induced diabetic rats for 21 days. The hepatoprotective effects were investigated in the liver tissues sections. There was a significant increase in serum liver biochemical parameters (aspartate aminotransferase, alanine transaminase, and alkaline phosphatase), accompanied by a significant decrease in the level of total protein and albumin in the STZ-induced rats when compared with that of the normal group. The high-dose treatment group (200 mg/kg body wt) significantly restored the elevated liver function enzymes near to normal. This study revealed that rosemary extracts exerted a hepatoprotective effect. The results indicate that the extract exhibits the protective effect on tissues and prove its potentials as an antidiabetic agent.     

Modulation of glucose uptake in adipose tissue by nitric oxide-generating compounds

There is increasing evidence that endogenous nitric oxide (NO) influences adipogenesis, lipolysis and insulin-stimulated glucose uptake. We investigated the effect of NO released from S-nitrosoglutathione (GSNO) and S-nitroso N-acetylpenicillamine (SNAP) on basal and insulin-stimulated glucose uptake in adipocytes of normoglycaemic and streptozotocin (STZ)-induced diabetic rats. GSNO and SNAP at 0.2, 0.5, and 1 mM brought about a concentration-dependent increase in basal and insulin-stimulated 2-deoxyglucose uptake in adipocytes of normoglycaemic and STZ-induced diabetic rats. SNAP at 1.0 mM significantly elevated basal 2-deoxyglucose uptake (115.8 ± 10.4%) compared with GSNO at the same concentration (116.1 ± 9.4%;P 0.05) in STZ-induced diabetic rats. Conversely, SNAP at concentrations of 10 mM and 20 mM significantly decreased basal 2-deoxyglucose uptake by 50.0 ± 4.5% and 61.5 ± 7.2% respectively in adipocytes of STZ-induced diabetic rats (P 0.05). GSNO at concentrations of 10 mM and 20 mM also significantly decreased basal 2-deoxyglucose uptake by 50.8 ± 6.4% and 55.2 ± 7.8% respectively in adipocytes of STZ-induced diabetic rats (P 0.05). These observations indicate that NO released from GSNO and SNAP at 1 mM or less stimulates basal and insulin-stimulated glucose uptake, and at concentrations of 10 mM and 20 mM inhibits basal glucose uptake. The additive effect of GSNO or SNAP, and insulin observed in this study could be due to different mechanisms and warrants further investigation.     

Intraruminal infusion of n-butyric acid induces an increase of ruminal papillae size independent of IGF-1 system in castrated bulls

Abstract

The objective of this study was to explore morphological alterations of rumen papillae induced by n-butyric acid in relation to the insulin-like growth factor (IGF) system in adult castrated bulls. Three animals fitted with rumen cannula were fed twice daily at a low and high nutritional level (LL and HL), i.e., at 1.1 × maintenance (M) and 1.6 × M, respectively. Diets contained artificial dried grass and concentrate (74:26 and 52:48). Bulls received no (B0) or daily intraruminal infusions of 500 g n-butyric acid (B500) over 14 d. The infusion started 1 h after the morning feeding (9:00) and lasted for 3.5 h. Thus, four treatments (B0LL, B500LL, B0HL, and B500HL) were compared. Blood and rumen mucosa samples from the atrium ruminis were taken at the last day of each period. Length, width and surface of rumen papillae were greater (p < 0.001) in B0HL than in B0LL. Treatment with n-butyric acid resulted in an increase of the papillae surface of 20 – 40% (p = 0.047) for both nutritional levels as compared to periods without n-butyric acid treatments. The higher nutritional level and intraruminal n-butyric acid infusion induced epithelial cell death. The percentage of proliferative cells was doubled by n-butyric acid treatment. The mRNA of IGF-1 and IGF type 1 receptor (IGF-1R), as well as IGF-1R binding capacity were unaffected by butyric acid treatments. The abundance of IGF-1 mRNA tended to be lower (p = 0.1) and IGF-1R abundance was lower (p = 0.03) in response to the HL. The plasma IGF-1 concentration was lower with butyric acid treatment (p < 0.01), but was unaffected by the nutritional level. In conclusion, under described experimental preconditions of daily short-time intraruminal n-butyric acid infusion alterations of rumen papillae morphology is not mediated by ruminal IGF type 1 receptor and by local IGF-1 expression in papillae in castrated bulls.     

Long-term exposure to a pulsed magnetic field (1.5 mT, 25 Hz) increases genomic DNA spontaneous degradation

The aim of this work is to investigate whether long-term pulsed magnetic field (MF) has genotoxic activity by induction of DNA damage on DNA molecules in vitro, in the absence of repair mechanisms. Yeast genomic DNA prepared by phenol extraction from S. cerevisiae cultures and the commercial DNA molecular weight marker Hyperladder I (HL-I) were exposed to 1.5?mT peak, pulsed 25?Hz MF, 8?h/day, 16 days. The total content of DNA (undamaged and damaged DNA) decreased during the exposure of genomic DNA to MF. On day 16 of exposure the DNA content was 41?±?8.1%. In addition, the undamaged DNA decreases until 6.2?±?3.1% for unexposed control samples and until 0.3?±?0.1% for pulsed MF-treated samples at day 16 of exposure. Therefore, the pulsed MF induced at day 16 an increase of 20.7-fold more degradation of DNA molecules >10?000?bp (undamaged DNA) than that observed for unexposed control samples. However, no effect was observed for HL-I DNA marker exposures. We conclude that long-term exposure to a pulsed MF (1.5?mT peak, 25?Hz, 8?h/day, 16 days) induces an increment in the DNA spontaneous degradation of yeast genomic DNA.