Comparative Effects of Metformin and Glibenclamide on Aortic Reactivity to Vasodilator and Vasoconstrictor Agents in STZ-Induced Diabetic Rats: Comparative effect of metformin and glibenclamide in diabetic rats

Diabetes is an important risk factor for cardiovascular events. Endothelial dysfunction is the main cause of disability and death in diabetic patients. The present study investigates the effects of metformin and glibenclamide on vasoconstrictive and vasodilative responses in the diabetic rat aorta. Rats were divided into four experimental groups (control, STZ-diabetic, metformin and glibenclamide treated diabetic rats). The treated rats received metformin (300 mg/kg) or glibenclamide (5 mg/kg) daily by gavage for 6 weeks.Thoracic aortic rings were mounted in an organ bath system, then contractile and dilatation responses induced by acetylcholine (ACh), phenylephrine (PE), potassium chloride (KCl), and sodium nitroprusside (SNP) were evaluated in different situations.Blood glucose level in glibenclamide group in days 24 and 45 were significantly lower than diabetic group. Metformin and glibenclamide significantly reduced the contractile responses to higher concentrations of PE (10-6 - 10-5 M) compared to diabetic group. Metformin and glibenclamide significantly reduced the contractile responses to concentrations of KCl (50 and 60 mM) compared to diabetic group. The relaxation responses to Ach 10-8 M, was increased in metformin and glibenclamide groups compared to the diabetic group. The relaxation responses to Ach 10-7 - 10-5 M were significantly higher in both treated groups compared to diabetic group. The chronic administration of metformin or glibenclamide has a significant hypoglycemic effect and improves aortic reactivity to vasoconstrictor and vasodilator agents in STZ-induced diabetic rats. No significant difference was found regarding the effects of metformin and glibenclamide on vasoconstrictive and vasodilative responses in aorta

The effects of hydroalcoholic extract of Nigella sativa seed on oxidative stress in hippocampus of STZ-induced diabetic rats

Objective: Oxidative stress plays an important role in the etiology of diabetic complications. Diabetes impairs hippocampus neurogenesis, synaptic plasticity, and learning. The aim of this study was to investigate the effects of hydroalcoholic extract of Nigella sativa seed on oxidative stress in STZ-induced diabetic rats' hippocampus. Materials and Methods: Diabetes induced by 60 mg/kg STZ, i.p, and the rats were divided into five experimental groups (n=8-10 in each group) including control (received 0.5 ml normal saline), untreated STZ-diabetic (received 0.5 ml normal saline), and treated rats received Nigella sativa extract (200 and 400 mg/kg) or metformin (300 mg/kg) by gavage for 42 days. Serum glucose concentration and body weight as well as hippocampus tissue malondialdehyde and thiollevels were determined by calorimetric assay. Results: Serum glucose level in the diabetic rats treated with 200 mg/kg Nigella sativaextract at the days 24 and 45 decreased in comparison to untreated diabetic group (

Hypothyroidism and Ramadan fasting

Introduction: Fasting during the holy month of Ramadan is an obligation for all adult, healthy Muslims. As several studies have indicated, both fasting and energy restriction can alter thyroid hormone metabolism and affect the clinical features and well-being of hypothyroid patients. Hypothyroidism is more prevalent among women and the elderly. Its prevalence has been reported to be 4-8% of the general population. Despite the large body of animal research on fasting, few human studies have focused on Ramadan fasting and its impacts on hypothyroid patients. Materials & Methods: PubMed and Google scholar databases were searched using keywords such as Ramadan, fasting, hypothyroidism, and food restriction. Animal and human studies, which were highly relevant to the topic, were selected. Results: Four animal and 7 human studies were included in this article. We found that levothyroxine dosage should be increased for hypothyroid patients from the beginning of the month until 15-20 days after the end of Ramadan. Discussion: Fasting can change the concentration of thyroid hormones, thyroid-stimulating hormone level, and the associated metabolisms both in animals and humans. As the results indicated, hypothyroid individuals, who fast during the month of Ramadan, particularly women and the elderly, may suffer from thyroid hormone changes. For these patients, levothyroxine dosage should be increased to 25-50 µg/per day from the beginning of Ramadan until 15-20 days after the end of this month. Conclusion: An increased dose of levothyroxine during Ramadan is recommended for hypothyroid patients, particularly women and the elderly

Renal injury, nephrolithiasis and Nigella sativa: A mini review

Objective: The incidence and prevalence of kidney stone is increasing worldwide. After the first recurrence the risk of subsequent relapses is higher and the time period between relapses is shortened. Urinary stones can be severely painful and make a huge economic burden. The stone disease may increase the vulnerability of patients to other diseases such as renal failure. Medicinal herbs are rich sources of antioxidants which are increasingly consumed globally for their safety, efficacy and low price. Nigella sativa is a spice plant that is widely used for prevention and treatment of many ailments in Muslim countries and worldwide. This review aims at investigation of the effects of Nigella sativa on renal injury and stone formation. Materials and Method: The scientific resources including PubMed, Scopus, and Google scholar were searched using key words such as: nephrolithiasis, urolithiasis, kidney/renal stone, renal injury, renal failure, urinary retention and black seed, black cumin, Nigella sativa and thymoquinone.    Results: N. sativa and its main component, thymoquinone showed positive effects in prevention or curing kidney stones and renal failure through various mechanism such as antioxidative, anti-inflammatory, anti-eicosanoid and immunomodulatory effects. The putative candidate in many cases has been claimed to be thymoquinone but it seems that at least in part, particularly in kidney stones, the herbal melanin plays a role which requires further investigation to prove. Conclusion: N. sativa and its components are beneficial in prevention and curing of renal diseases including nephrolithiasis and renal damages

Beneficial Effects of Selective Orexin-A Receptor Antagonist in 4-aminopyridine-induced Seizures in Male Rats

Background: Orexins are excitatory neuropeptides which stimulate the central regulatory pathways. Orexins increase the penicillin-induced epileptic activity in rats. Orexin-A increases in different types of seizures and its elevated level is the characteristic feature in the epileptic children during polysomnography. Recently, the orexin receptor blockage has been reported to increase seizure threshold in mice; however, effect of the selective orexin-A receptor antagonist (SB-334867) on 4-aminopyridine (4-AP)-induced seizures has not been investigated. Materials and Methods: We used the intraperitoneal injection of 4-AP to induce seizure in male rats. Under urethane anesthesia, SB-334867 (50 and 100 nmol) was injected stereotaxically into the ventral hippocampal commissure. Using video recording, the effects of SB-334867 on electroencephalogram and tonic–clonic convulsions were compared to those that received diazepam or dimethyl sulfoxide (DMSO). Results: SB-334867 significantly decreased the duration of spike trains compared to DMSO-treated rats (P < 0.001) and reduced the duration of convulsive seizures (P < 0.05). Seizure onset was increased significantly by SB-334867, 50 nmol, compared to DMSO (P < 0.05) and diazepam (P < 0.01) treated rats. Conclusion: Antagonism of orexin-A receptor by a low-dose SB-334867 showed protective effects in 4-AP-induced seizure-like activities in anesthetized rats

Salix alba attenuated oxidative stress in the heart and kidney of hypercholesterolemic rabbits

Objective: Oxidative stress plays a critical role in the development of hypercholesterolemia-induced complications. This study evaluated the effects of aspirin and Salix alba hydroethanolic extract on oxidative stress in the heart and kidney of hypercholesterolemic rabbits. Materials and Methods: The antioxidant activity, as well as total phenolic and salicin content of S. alba (Sa) extract were assessed by DPPH radical scavenging activity, Folin-Ciocalteu and HPLC methods, respectively. Animals were divided into two groups of control (fed with normal chow), and HD (fed with high cholesterol diet for 6 weeks). Then, hypercholesterolemic animals allocated to the following treatment groups: CHO (received HD), Sa extract (HD plus extract 60 and 120 mg/kg), and aspirin (HD plus aspirin 120 mg/kg) and received the treatments on a daily basis for 6 weeks. MDA, GSH, and nitrite concentrations as well as the activities of SOD and CAT were evaluated in cardiac and kidney tissues. Results: The scavenging activity, total phenolic content and salicin were 19.1 µg/ml (IC50), 153.75 ± 3.6 mg of gallic acid/g, and 18.03 µg/mg, respectively. In comparison to CHO group, MDA levels were diminished in Sa and ASA groups but GSH levels were improved. NO metabolites increased in the heart of Sa 120 mg/kg group and in the kidney of all Sa and ASA treated groups. SOD activity increased only in the heart of Sa groups and in the kidney of Sa and ASA groups. CAT activity increased in the heart and kidney tissues of all Sa and ASA treated groups. Conclusion: The results showed S. alba extract improved redox homeostasis in heart and kidney tissues of hypercholesterolemic rabbits. The extract antioxidant property may be related to its phenolic content

Beneficial Effect of Leptin on Spatial Learning and Memory in Streptozotocin-Induced Diabetic Rats

Background: Diabetes mellitus is a chronic disease which may be accompanied by cognitive impairments. The expression of the obesity gene (ob) is decreased in insulin-deficient diabetic animals and increased after the administration of insulin or leptin. Plasma leptin levels are reduced in the streptozotocin (STZ)-induced diabetic rats. Therefore, the deleterious effects of diabetes on memory may be due to the reduction of leptin. Aims: Investigate the effect of subcutaneous injection of leptin on spatial learning and memory in STZ-induced diabetic rats. Study Design: Animal experimentation. Methods: The rats were divided into three groups: 1- control, 2- diabetic, and 3- diabetic-leptin. Diabetes was induced in groups 2 and 3 by STZ injection (55 mg/kg) intraperitoneally (i.p). The animals received leptin (0.1 mg/kg) or saline subcutaneously (s.c) for 10 days before behavioral studies. Then, they were examined in the Morris water maze over 3 blocks after 3 days of the last injection of leptin. Results: The travelled path length and time spent to reach the platform significantly increased in the diabetic group (p<0.001) and decreased with leptin treatment (p<0.01 & p<0.001 respectively); also, a significant increase in path length and time was observed between the diabetic-leptin group and the diabetic group (p<0.01, p<0.001, respectively) in the probe test. Conclusion: Leptin can exert positive effects on memory impairments in diabetic rats

Effects of melatonin on biochemical factors and food and water consumption in diabetic rats

Background: Diabetic neuropathy is one of the serious problems due to microvessel vasculopathy in diabetes. It has been reported that hyperglycemia and hypertriglyceridemia are the underlying mechanisms in inducing and progression of diabetic neuropathy. The aim of the present study was to investigate the effects of melatonin on serum glucose and lipid levels, as well as food consumption and water intake in streptozotocin-induced diabetic rats. Materials and Methods: Eighty male Wistar rats were randomly assigned to six groups including; normal control group, diabetic control group and 4 diabetic experimental groups that received melatonin intraperitoneally at doses of 2.5, 5, 10, and 20 mg/kg at the end of sixth week after verification of neuropathy by means of evaluation of sciatic nerve conduction velocity (MNCV), for two weeks. Blood glucose and lipid levels, body weight, the amounts of food consumption, and water intake were determined in all groups at weeks 0 (before diabetes induction), 3, 6, and at the end of eighth week. Results: Treatment with melatonin reduced significantly the serum glucose (P < 0.001) and triglyceride (P < 0.05) levels, food consumption (P < 0.001), and water intake (P < 0.001) in diabetic rats at the end of eighth week. However, melatonin had no significant effect on body weight of diabetic animals. Conclusions: Treatment with melatonin could improve several signs of diabetes, including hyperglycemia, hypertriglyceridemia, polyphagia, and polydipsia. Therefore, melatonin may be used as an adjunct therapy in the treatment of diabetes

Kidney stone formation and antioxidant effects of Cynodon dactylon decoction in male Wistar rats

Objectives: The antioxidant capacity impairs in kidney and urinary bladder of animals with stone disease. Herbal medicine can improve the antioxidant condition of renal tissue. Cynodon dactylon (C. dactylon) is a medicinal plant with antioxidative and diuretic properties and different preparations of this plant have shown promising effects in stone disease. Assessment of the whole plant decoction to prevent kidney stone disease as well as its antioxidant effects was the aim of this paper.Materials and Methods: Fifty male Wistar rats were randomly divided into 5 experimental groups (n=10). One group was left without treatment and four groups received ethylene glycol (1% v/v) in drinking water for 6 weeks. Three doses of Cynodon dactylon aqueous decoction (12.5, 50 and 200 mg/kg BW) were added to the drinking water of groups 3-5. Finally, water intake, 24-hour urine volume, MDA, total thiol concentration and FRAP value were measured in the serum and kidney tissues. The CaOx depositions were evaluated by hematoxylin and eosin staining.Results: Compared to the ethylene glycol-treated group, 200 mg/kg C. dactylon, lowered stone incidents, decreased urine volume, increased FRAP/g Cr (43%) and thiol content (