Susceptibility of urea and uric acid levels to neurohormone influence in the freshwater pulmonate,lymnaea acuminata

Effects of pooled ganglionic extract on the urea and uric acid levels from blood, hepatopancreas, mantle and kidney of the pulmonate L. acuminata have been analysed. Blood urea and mantle uric acid were significantly (P<0.005 and P<0.05 respectively) increased following injection with pleuroparietalpedal-visceral (PPPV Complex) ganglia homogenate within 2 hrs. On the contrary hepatopancreas urea and kidney uric acid levels were significantly (P<0.00) lowered. Cerebral ganglia homogenate and boiled extract of PPPV complex did not provoke any significant change in urea and uric acid levels. It is advocated that (a) neurohormone(s) which is (are) heat-labile and originate from the PPPV complex, influence(s) the nitrogen end-products in these snails.     

Effect of Urease-Induced Hyperammonemia on Metabolism of Guanidino Compounds

We previously reported that guanidino compounds produced by the catabolism of arginine play an important role in the pathophysiology of acute hyperammonemia. In order to understand the metabolism of guanidino compounds during sustained hyperammonemia, we investigated the effect of intraperitoneal urease injection (800 IU/kg) on the levels of guanidino compounds in blood, liver, kidney, and brain of rats. Control rats received an equal volume of saline. Eight hours following injection, rats were sacrificed and blood and tissues were removed. Ammonia and urea were determined by enzymatic and colorimetric assays, respectively. Guanidino compounds were analyzed by high-performance liquid chromatography. Blood and tissue ammonia were significantly increased and urea decreased in urease-treated animals. Blood and kidney arginine levels were significantly decreased although hepatic arginine was increased following urease injection. Elevated hepatic arginine may be due to the rapid conversion of urea to ammonia by urease and the development of a futile urea cycle. Catabolites produced by the transamidination of arginine were significantly decreased in the blood, liver, kidney, and brain of urease-treated rats, whereas acetylation of hepatic arginine to α-N-acetylarginine was increased. Blood and tissue guanidinosuccinic acid levels were not elevated during urease induced hyperammonemia, supporting the hypothesis that urea is a precursor for the synthesis of guanidinosuccinic acid.     

Increase of uricogenesis in the kuruma shrimp Marsupenaeus japonicus reared under hyper-osmotic conditions

Tissues of kuruma shrimp Marsupenaeus japonicus Bate (5.7+/-1.1 g) reared in salinities of 18, 26, 34 and 42 were examined for levels of nucleotide-related compounds, ammonia, urea and uric acid, and activities of xanthine dehydrogenase (XDH), xanthine oxidase (XOD) and uricase. Levels of total nucleotide-related compounds, including xanthine and hypoxanthine, in gill increased directly with salinity, whereas these same levels in hepatopancreas were inversely related with salinity. Hemolymph ammonia, urea and uric acid levels, and epidermal ammonia, urea and uric acid levels increased directly with salinity, whereas hepatopancreas ammonia and uric acid and gill uric acid levels were inversely related to salinity. Activities of XDH and XOD in hepatopancreas increased directly with salinity level, whereas no significant difference of uricase activity in hepatopancreas was observed among the four salinities. It is concluded M. japonicus exhibited uricogenesis and uricolysis, and an increase of uricogenesis occurred for the shrimp under hyper-osmotic conditions (salinity of 42). Uric acid produced in the hepatopancreas was transported and accumulated in the epidermis, and removed along with the spongy connective tissue at the time of molting.     

Sublethal Effect of Copper Toxicity Against Histopathological Changes in the Spiny Lobster, <Emphasis Type="Italic">Panulirus homarus</Emphasis> (Linnaeus, 1758)

The tissue damage induced by various organic pollutants in aquatic animals is well documented, but there is a dearth of information relating to the histological alterations induced by copper in the spiny lobster. In the present study, intermoult juveniles of the spiny lobster Panulirus homarus (average weight 150–200 g) were exposed to two sublethal concentrations of the copper (9.55 and 19.1 μg/l) for a period of 28 days. The muscle, hepatopancreas, midgut, gills, thoracic ganglion and heart of the lobsters were then dissected out and processed for light microscopic studies. Exposure to copper was found to result in several alterations in the histoarchitecture of the muscle, hepatopancreas, midgut, gills, thoracic ganglion and heart of P. homarus. The alterations included disruption and congestion of muscle bundle in muscle tissue; blackened haemocytes; distended lumen and F cell; necrosis of the tubules of the hepatopancreas; disarrangement of circular muscle of the midgut; accumulation of haemocytes in the haemocoelic space; swelling and fusion of lamellae; abnormal gill tips; hyperplastic, necrotic, and blackened secondary gill lamellae of the gills; damaged neurosecretory cell and sensory and motor fibre; necrotic of the thoracic ganglion; dispersedly arranged muscle bands; clumped satellite cells and nucleus of the heart. The results obtained suggest that the muscle, hepatopancreas, midgut, gills, thoracic ganglion and heart of lobsters exposed to copper were structurally altered. Such alterations could affect vital physiological functions, such as absorption, storage and secretion of the hepatopancreas, digestion of gut and respiration, osmotic and ionic regulations of the gills, which in turn could ultimately affect the survival and growth of P. homarus. Thus, all possible remedial measures should be adopted to prevent the occurrence of copper contamination in the aquatic environment.     

Hormonal control of blood chloride in the marine pulmonate,onchidium verruculatum

A search for endocrinological factors inO. verruculatum revealed that three hours after right pleural ganglion extirpation blood chloride is significantly (P<0.01) sinked. Administration of right pleural ganglion homogenate (I gang/animal) into depleuralised snails significantly (P<0.001) enhances the blood chloride level after three hrs. Removal of the ganglia other than the right pleural provokes a significant (P<0.01) decline in blood chloride profile in these animals. However, replacement therapy either via homogenate injection or reimplantation of the particular ganglion into extrapleural ganglionectomised animals is ineffective in restoring the chloride levels. It is argued that only right pleural ganglia control blood chloride via vascular channels.     

Effects of vanadyl sulfate on kidney in experimental diabetes

The aim of this work was to investigate the biochemical and histological effects of vanadyl sulfate on blood glucose, urea, and creatinine in serum and nonenzymatic glycosylation and glutathione levels in kidney tissue of normal and streptozotocin (65 mg/kg) diabetic rats. Vanadyl sulfate was administered by gavage at a dose of 100 mg/kg. After 60 d of treatment, serum urea, creatinine, and blood glucose levels significantly increased in the diabetic group but not so in the vanadyl sulfate, which showed significantly reduced serum urea and blood glucose levels and a nonsignificant reduction of serum creatinine levels. Nonenzymatic glycosylation was increased and the glutathione level was decreased in the kidney tissue of diabetic rats. Treatment with vanadyl sulfate reversed these effects. Degenerative changes were detected in diabetic animals by electron and light microscopy. Although there are individual differences in diabetic animals given vanadium, some reduction of degenerative changes were observed.     

An increase of uricogenesis in the Kuruma shrimp Marsupenaeus japonicus under nitrite stress

Kuruma shrimp Marsupenaeus japonicus Bate, under the stress of 0.36 and 1.39 mM nitrite at 30 per thousand (parts per thousand, g kg(-1)) for 48 h, were examined for nucleotide-related compounds, specific activities of xanthine dehydrogenase (XDH), xanthine oxidase (XOD), and uricase. The levels of total nucleotide-related compounds, including xanthine and hypoxanthine, in the gill increased directly with ambient nitrite, whereas the levels of total nucleotide-related compounds, including xanthine and hypoxanthine, in the hepatopancreas were inversely related to ambient nitrite. Specific activity of XOD in the hepatopancreas increased directly with ambient nitrite, whereas no significant difference in uricase activity in the hepatopancreas was observed among three treatments. In another experiment, M. japonicus, following 48 h exposure to 0.36 and 1.39 mM nitrite, were examined for ammonia, urea, and urate levels in tissues. Hemolymph urea and exoskeleton urate levels increased directly with ambient nitrite, whereas hemolymph urate and exoskeleton urea levels were inversely related to ambient nitrite. It is concluded that M. japonicus exhibited uricogenesis and uricolysis, and an increase of uricogenesis occurred for the shrimp under nitrite stress. Urate produced in the hepatopancreas was transported and accumulated in the epidermis, and removed along with the exoskeleton at the time of molting.     

阿魏酸对糖尿病大鼠肾脏足细胞nephrin、podocin蛋白表达的影响

目的：研究阿魏酸（FA）对链脲佐菌素（STZ）致糖尿病大鼠肾脏足细胞损伤的影响,并探讨其可能的机制。方法：雄性SD大鼠尾静脉一次性注射STZ （40 mg/kg,i.v.）,72 h后将血糖高于16.7 mmol/L者视为糖尿病造模成功,将其随机分为模型组、阿魏酸组,每组10只;另取10只雄性SD大鼠作为对照组;阿魏酸组（100 mg/kg,i.g.,qd）,从大鼠血糖升高第5周开始给药,连续8周。测定空腹血糖、体重、肾脏脏器系数、血清尿素氮、肌酐含量;HE染色观察肾组织病理变化;免疫组化测定肾组织nephrin、podocin蛋白表达。结果：与对照组比较,模型组肾脏脏器系数增大,肾功能下降;病理学显示肾脏细胞萎缩,排列不整齐,并伴有间质增生;足细胞nephrin、podocin蛋白表达明显减少,阿魏酸组明显改善上述指标。结论：阿魏酸具有改善STZ致糖尿病大鼠肾脏功能的作用,其机制可能与上调肾脏足细胞nephrin、podocin蛋白表达有关。     

Clinical Biochemistry and Hematology of the Elusive Sun‐Tailed Monkey (Cercopithecus solatus) in Gabon: Inaugural Data From the Only Semifree Ranging Colony in the World

Clinical blood biochemistry and hematology are valuable tools to evaluate health and welfare in many animal species. In order to document the general biology of one of the most poorly known nonhuman primate species, and contribute to its conservation, the clinical blood biochemistry and hematology of the sun‐tailed monkey (Cercopithecus solatus Harrisson) was investigated in its range of endemicity in Gabon. Data derived from 26 years of clinical monitoring of the only semicaptive colony of this species in the world, housed at CIRMF (Franceville, Gabon), were analyzed in order to establish reference values of age–sex classes. Consistent with previous reports in other primate species, age and sex significantly affected a number of biochemical and hematological parameters in C. solatus. Hematological analyses demonstrated significant differences in red blood cells, hemoglobin (HB), and hematocrit (HT), with males showing significantly greater values than females. In contrast, neutrophil counts were greater in females. An ontogenetic effect was detected for HB, HT, eosinophil, and monocyte counts, while lymphocytes significantly decreased with age. Biochemical analyses also showed significant differences, with females displaying greater cholesterol and alanine aminotransferase levels. Increase in levels of blood urea and aspartate aminotransferase coupled with decrease in albumin in old individuals suggested declining kidney, liver, and muscle functions with age. Interspecific comparisons were conducted and the effects of the unique semifree‐ranging setting on the validity and value of the results presented are discussed. The reference values established will be useful in further ecological, parasitological, and virological studies of the sun‐tailed monkey.     

Downregulation of Apoptosis and Modulation of TGF-β1 by Sodium Selenate Prevents Streptozotocin-Induced Diabetic Rat Renal Impairment

To investigate whether sodium selenate treatment would impact on the onset of diabetic nephropathy, we examined blood glucose, serum biochemical components, and interrelationship between oxidative stress, TGF-β1, and apoptosis in streptozotocin (STZ) induced diabetic rats. Sixty male Wistar rats were divided into six groups. Group I (n = 10), normal control; Group II (n = 10), diabetic control; Group III (n = 10), sodium selenate (16 μmoles/kg) + diabetic; Group IV (n = 10), sodium selenate (32 μmoles/kg) + diabetic; Group V (n = 10), sodium selenate (16 μmoles/kg) control; and Group VI (n = 10), sodium selenate (32 μmoles/kg) control. Sodium selenate was administered via orogastric route for 10 weeks. In the diabetic group, diabetes was induced by single intraperitoneal injection of STZ (50 mg/kg). The levels of blood glucose were estimated and total cholesterol, high-density lipoprotein (HDL) cholesterol, triglycerides, creatinine, urea, and albumin were detected in serum. Antioxidant status was examined by measuring the superoxide dismutase (SOD), catalase, glutathione, and lipid peroxidation in kidney tissues. Histopathological studies were performed in the kidney tissue sections. The expression of TGF-β1 was estimated by the immunohistochemical analysis in kidneys. Apoptotic study in kidney was performed using the TdT-mediated dUTP nick end labeling technique. It was observed that blood glucose, serum, total cholesterol, HDL cholesterol, triglycerides, creatinine, urea, and albumin were significantly higher in diabetic control groups. Diabetic + sodium selenate (16 and 32 μmoles/kg) significantly reduced blood glucose, serum, total cholesterol, HDL cholesterol, triglycerides, creatinine, urea, and albumin levels. Selenium-treated groups significantly increased antioxidant enzyme activities (SOD, catalase, and glutathione) in kidneys of diabetic rats. All enzyme activities of selenium control groups did not differ compared with the normal control. Sodium selenate reduces significantly lipid peroxidation in diabetic rats. Cellular architecture of the diabetic rats was altered whereas sodium selenate administration rectifies the degenerative changes of the kidney. Profound immunopositivity of TGF-β1 was observed in the glomerular and tubulointerstitial cells of diabetic rat kidney. Immunopositivity of TGF-β1 was significantly reduced in both low and high dose of sodium-selenate-treated rats (P < 0.05, P < 0.01). High numbers of apoptotic cells were observed in diabetic rats whereas sodium selenate in both doses significantly reduces the incidence of apoptosis (P < 0.05, P < 0.01). We conclude herein that sodium selenate has the potential to play a significant role in limiting the renal impairment by altering the apoptosis and TGF-β1 in experimental diabetic rats.     

Increases in urea synthesis and the ornithine-urea cycle capacity in the giant African snail, Achatina fulica, during fasting or aestivation, or after the injection with ammonium chloride

The objectives of this study are to determine whether a full complement of ornithine-urea cycle (OUC) enzymes is present in the hepatopancreas of the giant African snail Achatina fulica, and to investigate whether the rate of urea synthesis and the OUC capacity can be up-regulated during 23 days of fasting or aestivation, or 24 hr post-injection with NH(4)Cl (10 micromol g(-1) snail) into the foot muscle. A. fulica is ureotelic and a full complement of OUC enzymes, including carbamoyl phosphate synthetase III (CPS III), was detected from its hepatopancreas. There were significant increases in the excretion of NH(4)(+), NH(3) and urea in fasting A. fulica. Fasting had no significant effect on the tissue ammonia contents, but led to a progressive accumulation of urea, which was associated with an 18-fold increase in the rate of urea synthesis. Because fasting took place in the presence of water and because there was no change in water contents in the foot muscle and hepatopancreas, it can be concluded that the function of urea accumulation in fasting A. fulica was unrelated to water retention. Aestivation in arid conditions led to a non-progressive accumulation of urea in A. fulica. During the first 4 days and the last 3 days of the 23-day aestivation period, experimental snails exhibited significantly greater rates of urea synthesis compared with fasted snails. These increases were associated with significant increases in activities of various OUC enzymes, except CPS III, in the hepatopancreas. However, the overall urea accumulation in snails aestivated and snails fasted for 23 days were comparable. Therefore, the classical hypothesis that urea accumulation occurred to prevent water loss through evaporation during aestivation in terrestrial pulmonates may not be valid. Surprisingly, there were no accumulations of ammonia in the foot muscle and hepatopancreas of A. fulica 12 or 24 hr after NH(4)Cl was injected into the foot muscle. In contrast, the urea content in the foot muscle of A. fulica increased 4.5- and 33-fold at hour 12 and hour 24, respectively, and the respective increases in the hepatopancreas were 4.9- and 32-fold. The exogenous ammonia injected into A. fulica was apparently detoxified completely to urea. The urea synthesis rate increased 148-fold within the 24-hr experimental period, which could be the greatest increase known among animals. Simultaneously, there were significant increases in activities of glutamine synthetase (2.5-fold), CPS III (3.1-fold), ornithine transcarbamoylase (2.3-fold), argininosuccinate synthetase+lyase (13.6-fold) and arginase (3.5-fold) in the hepatopancreas 12 hr after the injection of NH(4)Cl. Taken altogether, our results support the view that the primary function of urea synthesis through the OUC in A. fulica is to defend against ammonia toxicity, but suggest that urea may have more than an excretory role in terrestrial pulmonates capable of aestivation.     

Impact of Hemidesmus indicus R.Br. extract on ethanol-mediated oxidative damage in rat kidney

Abstract

The antioxidant effect of the ethanolic extract of Hemidesmus indicus R.Br. root (EHI), an indigenous Ayurvedic medicinal plant in India, was studied in rats with ethanol-induced nephrotoxicity. Administering 5 g/kg body weight/day of ethanol for 60 days to male Wistar rats resulted in significantly elevated levels of serum urea, creatinine and uric acid as well as kidney thiobarbituric acid reactive substances (TBARS), lipid hydroperoxides (LOOH) and conjugated dienes (CD) as compared to those of the experimental control rats. Decreased levels of kidney superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), reduced glutathione (GSH), vitamin C and vitamin E were also observed on alcohol administration as compared with those of the experimental control rats. EHI was administered at a dose of 500 mg/kg body weight/day for the last 30 days of the experiment to rats with ethanol-induced kidney injury, which significantly decreased the levels of serum urea, uric acid and creatinine as well as kidney TBARS, LOOH and CD and significantly elevated the activities of SOD, CAT, GPx, GSH, vitamin C and vitamin E in kidney as compared to that of untreated ethanol-administered rats. Histopathological observations also correlated with the biochemical parameters. Thus, the data indicate that treatment with EHI offers protection against free radical-mediated oxidative stress in kidney of animals with ethanol-induced nephtrotoxicity.     

Seasonal variation of energy metabolism in ghost crab Ocypode quadrata at Siriú Beach (Brazil)

The aim of this study was to analyze the seasonal variations of carbohydrate and lipid metabolism of the ghost crab Ocypode quadrata (Fabricius, 1787) on a sandy beach in the southern region of Brazil. Crabs and hemolymph samples were collected monthly in the field. Hepatopancreas, gills, gonads and claw muscles were used for glycogen determination. In males, blood glucose levels increased in the summer and in the winter. The glycogen values increased significantly in the hepatopancreas in the winter, but remained constant in the muscle, gonads and gills. In females, hemolymph glucose levels, glycogen values in the hepatopancreas and in the gills remained constant throughout the year; however, muscular glycogen increased in the spring and gonad glycogen decreased in the summer. Hemolymph triglyceride levels of males and females and total cholesterol of males decreased significantly in the spring. In females, a significant increase of total cholesterol levels was found in the winter. The findings suggest that in O. quadrata lipids seem to be an important reserve of energy used during reproduction, both in males and females, while glycogen may be used during periods of intense activity or fasting.     

Estimation of Absidia ramosa infection in the brain and kidneys of cortisone-treated mice by chitin assay

Chitin assay was used to measure Absidia ramosa infection in the brain and kidneys of cortisone-treated mice. Mice dying 3 days after challenge had brain and kidney infection but normal renal function as determined by measurement of blood urea levels. Mice dying 5 or 6 days after challenge had infection in the kidneys but not the brain and were uraemic.     

Treatment of radiation nephropathy with captopril.

Both experimental and clinical radiation nephropathy are typically progressive, evolving to kidney failure over weeks to months. Other late radiation injuries (spinal cord, lung) are also progressive and have no known specific antidote. Recent reports of the efficacy of captopril in modifying radiation injury of the lung prompted this trial of captopril in treating established radiation nephropathy. Six months after 15-27 Gy in 12 fractions bilateral renal irradiation, 72 rats with blood urea nitrogen > 4.1 mmol/liter were started on captopril (500 mg/liter) or no drug in the drinking water. Subsequent survival was significantly enhanced in rats receiving captopril as opposed to no drug (P = 0.0013), and the rate of rise of blood urea nitrogen was significantly diminished (P < 0.0001) in the animals on captopril. Urine protein excretion was also reduced from initially elevated levels in the rats on captopril compared to levels in rats given no drug. We conclude that captopril therapy preserves kidney function, reduces proteinuria, and enhances survival in experimental radiation nephropathy.     

Comparative evaluation of hepatotoxic and nephrotoxic effects of aroclors 1221 and 1254 in female rats

Polychlorinated biphenyls (PCBs) are persistent environmental pollutants. This study compared effects of two PCB mixtures, Aroclors 1221 (A1221) and 1254 (A1254) on serum levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), urea, creatinine and uric acid in female rats. Histopathological changes in the liver and kidney were also examined. A group of adult Wistar rats served as controls. Groups II and III were subcutaneously injected with A1221 and A1254 at 10 mg/kg every other day for 6 weeks. At the end of this period, all animals were decapitated and blood samples were collected. Serum urea, creatinine, uric acid, ALT, AST and ALP levels were determined. Liver and kidney were collected for histopathological examination. They were fixed in formaldehyde and processed for light microscopy. Both A1221 and 1254 significantly elevated serum ALT (p < 0.05) and AST (p < 0.01) levels compared to the control group. Serum ALP values were significantly increased by A1221 (p < 0.05), but they were unaffected in the A1254 group. Treatment with both A1221 and A1254 significantly increased serum levels of urea (p < 0.05), creatinine (p < 0.01) and uric acid (except in the A1221 group; p < 0.005). Distinct histopathological changes including renal corpuscular atrophy, peritubular vascular congestion and dilated cortical tubules, sinusoidal dilatation, congestion and mononuclear cell infiltration were observed. These findings suggest that PCBs may cause nephrotoxicity and hepatotoxicity in female rats.     

Nitric oxide scavenging by cell-free hemoglobin may be a primary factor determining hypertension in polycythemic patients

Abstract

We tested the hypothesis that hypertension associated with polycythemia vera (PV) may be related to hemoglobin released from erythrocytes (cell-free hemoglobin, fHb). We assessed hematocrit, mean arterial pressure (MAP), blood viscosity, and the level of fHb and nitrite/nitrate (NO_x) in the plasma of 73 PV patients and 38 healthy controls. The effect of isovolemic erythrocytapheresis (ECP) on the considered parameters was also studied. From the whole group of PV patients a subset of subjects with normal (normotensive patients, n = 16) and elevated MAP (hypertensive patients, n = 57) can be subtracted.

It was found that in comparison with healthy controls, PV patients have significantly (p ≤ 0.01) elevated Hct (0.567 vs. 0.422), blood viscosity (5.45 vs. 3.56 cP), MAP (106.8 vs. 93.8 mmHg), plasma fHb (9.7 vs. 2.8 mg/dL), and NO_x levels (34.1 vs. 27.5 μM). Compared with normotensive patients, hypertensive PV patients demonstrated a higher rise in fHb (10.2 vs. 8.0) and plasma NO_x levels (35.8 vs. 31.0). In PV patients, fHb positively correlates with MAP (r = 0.489), NO_x levels (r = 0.461), hematocrit (r = 0.428), and viscosity (r = 0.393). Blood viscosity positively correlated with hematocrit (r = 0.894), but not with other considered parameters. In PV patients MAP poorly correlated with hematocrit, whereas the correlation between MAP and NO_x altered from ? 0.325 (healthy control) to + 0.268 (PV patients). ECP procedure was associated with a significant (p < 0.01) reduction of hematocrit, fHb, blood viscosity, and MAP. In the normotensive subgroup of PV patients the ECP procedure did not affect MAP. It can be concluded that accelerated scavenging of nitric oxide by fHb rather than high Hct may be a key factor determining the development of hypertension in PV patients.     

Hypothyroid States Mitigate the Diabetes-Induced Reduction of Calbindin D-28k, Calretinin, and Parvalbumin Immunoreactivity in Type 2 Diabetic Rats

In this study, we investigated the differences in calbindin D-28k (CB), calretinin, (CR) and parvalbumin (PV) immunoreactivity in the hippocampus of Zucker diabetic fatty (ZDF) rats and Zucker lean control (ZLC) rats. In addition, we observed the effects of hypothyroidism on the levels of immunoreactivity of these proteins in ZDF rats. For this study, 7-week-old ZDF rats were used, and methimazole treatment was continued for 5 weeks to induce hypothyroidism. The animals were sacrificed at 12 weeks of age. ZDF rats showed increased blood glucose levels compared to those in ZLC rats. Methimazole intervention significantly reduced total and free T3 levels, and it ameliorated the increase of blood glucose levels in ZDF rats. In ZLC rats, CB, CR, and PV immunoreactivity was detected in regions of the hippocampus proper. In vehicle-treated ZDF rats, CB, CR, and PV immunoreactivity was significantly decreased in the hippocampus. However, in the methimazole-treated rats, CB, CR, and PV immunoreactivity was significantly increased compared to that in the vehicle-treated rats. These results suggest that hypothyroidism ameliorated the diabetes-induced reduction of CB, CR, and PV immunoreactivity in the hippocampus.     

Curcumin alleviates acute kidney injury in a dry‐heat environment by reducing oxidative stress and inflammation in a rat model

Curcumin exhibits anti‐inflammatory and antioxidant activities. We investigated the protective effects of curcumin in a renal injury rat model under dry‐heat conditions. We divided Sprague‐Dawley rats into four groups: dry‐heat 0‐ (normal temperature control group), 50‐, 100‐, and 150‐minute groups. Each group was divided into five subgroups (n = 10): normal saline (NS), sodium carboxymethylcellulose (CMCNa), and curcumin pretreated low, medium, and high‐dose (50, 100, and 200 mg/kg, respectively) groups. Compared to the normal temperature group, serum creatinine, blood urea nitrogen, urinary kidney injury molecule‐1, and neutrophil gelatinase‐associated load changes in lipoprotein (NGAL) levels were significantly increased in the dry‐heat environment group (P < .05); inducible nitric oxide synthase (iNOS) and cyclooxygenase‐2 (COX‐2) expression and malondialdehyde (MDA) and related inflammatory factor levels were increased in the kidney tissue. Superoxide dismutase (SOD) and catalase (CAT) levels were decreased. However, following all curcumin pretreatment, the serum levels of kidney injury indicators and NGAL were decreased in the urine compared to those in the NS and CMCNa groups (P < .05), whereas renal SOD and CAT activities were increased and MDA was decreased (P < .05). Renal tissues of the 150‐minute group showed obvious pathological changes. Compared to the NS group, pathological changes in the renal tissues of the 100‐ and 200‐mg/kg curcumin groups were significantly reduced. Furthermore, iNOS and COX‐2 expression and inflammatory factor levels were decreased after curcumin treatment. Curcumin exerted renoprotective effects that were likely mediated by its antioxidant and anti‐inflammatory effects in a dry‐heat environment rat model.