Downregulation of Bax/Bcl-2 Expression During Apoptosis in the Hippocampus of Diabetic Male Wistar Rats: Ameliorative Effects of Peganum harmala Seed Extract.

Background: Apoptosis is proposed as a possible mechanism for diabetes-induced hippocampal neuronal cell death. Numerous studies have suggested that the therapeutic properties of plants, such as antioxidant and anti-apoptotic, are effective in improving the complications of diabetes in the hippocampus. Objectives: This study aimed to evaluate the anti-apoptotic properties of Peganum harmala (P. harmala) in the brain hippocampal cells of diabetic rats. Methods: In this experimental study, 48 male Wistar rats were divided into six groups (n = 8) as follows: Control (C), diabetic (D), harmine (H), diabetic plus harmine (DH), seed extract (S), and diabetic plus seed extract (DS). A single dose of streptozotocin (STZ) (60 mg/kg) was enough to cause diabetes. Seed extract and harmine were given at 150 mg/kg and 6.5 mg/kg, respectively (daily by oral gavage for 28 days). The glucose levels in the blood were measured, and the histological staining of the hippocampus was examined. Percentages of apoptotic hippocampal cells were identified with flow cytometry. Bax and Bcl-2 expression was assayed via Real time- polymerase chain reaction (PCR) and Western blot. Results: In DH (P = 0.001) and DS (P = 0.01) rats, the mean fasting blood glucose level significantly reduced compared with the D group. Bax and Bcl-2 expression at both mRNA and protein levels significantly differed between the D group and other groups (P = 0.01). Harmine and the seed extract considerably reduced the Bax/Bcl-2 ratio in the hippocampal cells compared to the D group (P = 0.001). Conclusions: Streptozotocin-induced apoptosis in the hippocampus of diabetic rats was reduced by administering the seed extract of Peganum harmala. The P. harmala seed extract and its active ingredient, harmine, could be used as anti-apoptotic drugs.

Effect of treadmill exercise on catalepsy and the expression of the BDNF gene in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine -induced Parkinson in male NMRI mice.

OBJECTIVES: It is known that treadmill exercise has beneficial effects on the nervous system. The brain-derived neurotrophic factor (BDNF) plays a role in such effects. This study aimed at investigating effects of intermittent treadmill exercise-induced behavioral, histology, and immunohistochemistry (H&E, TH) measurement of brain interleukin-10 (IL-10) in a mice male model of Parkinson's disease (PD), which is induced by intraperitoneal injection of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), as well as the role of BDNF gene in exercise effects. MATERIALS AND METHODS: The animals were divided into Control (C), Saline (S), Parkinson (P), Exercise (E), and Parkinson + Exercise (PE) groups. Bar test was performed for the 21-day protocol with 5 days a week treadmill exercises. In this regard, brains were removed from the skull for H&E, TH, IL-10, and the expression of the BDNF gene using the MPTP male mice PD model. RESULTS: MPTP reduced the number of DA neurons in the substantia nigra (SNpc), whereas daily exercise administration on 1st, 7th, 14th, and 21st days significantly reduced the catalepsy duration induced by MPTP. The results of H&E and TH studies showed that MPTP significantly reduced the number of TH+ neurons in the SNpc compared with those of the control mice. The MPTP caused a marked decrease in basal protein levels of IL-10 in SNpc and corpus striatum in the Parkinson (P) group as compared with controls. Treatment with Exercise (E) group had the most BDNF expression (3.71), and the Parkinson (P) group also had the least BDNF expression (0.18) relative to controls. CONCLUSION: The treadmill exercise having neuroprotective effects in SNpc and corpus striatum has improved MPTP associated with motor deficits. It is considered as a non-pharmacological tool for the management of PD.

Adiponectin modulates synaptic plasticity in hippocampal dentate gyrus.

Recent studies have suggested the involvement of some metabolic hormones in memory formation and synaptic plasticity. Insulin dysfunction is known as an essential process in the pathogenesis of sporadic Alzheimer's disease (AD). In this study we examined whether adiponectin (ADN), as an insulin-sensitizing adipokine, could affect hippocampal synaptic plasticity. Field potential recordings were performed on intracerebroventricular (icv) cannulated urethane anesthetized rats. After baseline recording from dentate gyrus (DG) and 10min prior to high/low frequency stimulation (HFS/LFS), 10µl icv ADN (600nm) were injected. The slope of field excitatory postsynaptic potentials (fEPSP) and the amplitude of population spikes (PS) were recorded in response to perforanth path (PP) stimulation. Paired pulse stimuli and ADN injection without any stimulation protocols were also evaluated. Application of ADN before HFS increased PS amplitude recorded in DG significantly (P≤0.05) in comparison to HFS only group. ADN suppressed the potency of LFS to induce long-term depression (LTD), causing a significant difference between fEPSP slope (P≤0.05) and PS amplitude (P≤0.01) between ADN+LFS and ADN group. Paired pulse stimuli applied at 20ms intervals showed more paired pulse facilitation (PPF), when applied after ADN (P≤0.05). ADN induced a chemical long-term potentiation (LTP) in which fEPSP slope and PS amplitude increased significantly (P≤0.01 and P≤0.05, respectively). It is concluded that ADN is able to potentiate the HFS-induced LTP and suppress LFS-induced LTD. ADN caused a chemical LTP, when applied without any tetanic protocol. ADN may enhance the presynaptic release probability.

The effect of arsenite on spatial learning: Involvement of autophagy and apoptosis.

Spatial learning plays a major role in one's information recording. Arsenic is one of ubiquitous environmental toxins with known neurological effects. However, studies investigating the effects of arsenic on spatial learning and related mechanisms are limited. This study was planned toexaminethe effects of bilateral intra-hippocampal infusion of different concentrations of sodium arsenite (5, 10 and 100nM, 5µl/side) on spatial learning in Wistar rats. Moreover, we evaluated levels of LC3-II, Atg7 and Atg12 as reliable biomarkers of autophagy and caspase-3 and Bax/Bcl-2 ratio as indicators of apoptosis in the hippocampus. Interestingly, low concentrations of sodium arsenite (5 and 10nM) significantly increased spatial acquisition but pre-training administration of sodium arsenite100nM did not significantly alter spatial learning. LC3-II levels were significantly increased in groups treated with sodium arsenite 5 and 10nM and decreased in the group receiving arsenite 100nM compared to the control group. Atg7 and Atg12 levels were obviously higher in all groups treated with sodium arsenite compared to control. However, caspase-3 cleavage and Bax/Bcl-2 ratio were notably greater in 100nM, and lesser in 5nM arsenite group in comparison with control animals. The results of this study showed that the low concentrations of sodium arsenite could facilitate spatial learning. This facilitation could be attributed to neuronal autophagy induced by low concentrations of sodium arsenite. These findings may help to clarify the regulatory pathways for apoptosis and autophagy balance due to sodium arsenite.

The Effects of Levofloxacin on Testis Tissue and Spermatogenesis in Rat.

Levofloxacin is one of the Fluroquinoline antibiotic groups, which affect on controlling infections, especially in reproductive organs. It has therapeutic use in numerous countries, but little information exists on the effects of Levofloxacin on spermatogenesis when it is used for infectious treatment. The current study was designed to determine whether Levofloxacin influences testis tissue and spermatogenesis in rats. In this survey 50 male Wistar rats 6-8 weeks (250 ± 10 g) were used: normal salin as sham and control groups and 3 treatment groups (0.03, 0.06 and 0.08 mg Levofloxacin\kg body weight) during 60 days. The experimental groups were daily gavages. After 60 days, they were anesthetized with ether and testes were taken for histopathology studies, sperm parameters evaluation and several hormone concentrations. Although testosterone concentration was not affected by Levofloxacin levels, follicle stimulating hormone (FSH) and luteinizing hormone (LH) concentration significantly increased by Levofloxacin consumption in 0.03 and 0.06 mg Levofloxacin\kg body weight groups (P<0.01). Moreover, sperm concentration decreased linearly as Levofloxacin was increased (200, 192, 170, 128 and 75×10(6) sperm for control, sham, 0.03, 0.06 and 0.08 mg Levofloxacin\kg body weight, respectively, P<0.05). Testis tissue cuts in experimental group when the amount dosage of Levofloxacin increased cells solidarity to the primary and secondary spermatogonia. Adding Levofloxacin linearly reduced spermatocyte cells and amount of all cells in semenifer pipes tube (P<0.05). Levofloxacin as an antibiotic has histopathology effects on the spermatocyte cells, especially in high dose. Therefore, it might reduce fertility in male that requires further studies.

Effects of alpha-adrenoceptor agonists and antagonists on histamine-induced impairment of memory retention of passive avoidance learning in rats.

The effect of alpha-adrenoceptor agents on the impairment induced by histamine was measured for memory retention of passive avoidance learning in rats. Post-training intracerebroventricular (i.c.v.) injection was carried out in all the experiments. Histamine (5, 10 and 20 microg/rat) reduced, while a histamine H(1) receptor antagonist, chlorpheniramine (0.1, 1 and 10 microg/rat), increased memory retention. The histamine H(2) receptor antagonist, ranitidine (0.1, 1, 10 and 20 microg/rat), did not elicit any response in this respect. Different doses of chlorpheniramine but not ranitidine reversed the histamine-induced impairment of memory. Clonidine and prazosin decreased, but yohimbine and phenylephrine increased, memory retention. Yohimbine decreased the inhibitory response to histamine. Phenylephrine, clonidine and prazosin did not alter the histamine effect. It is concluded that a histamine-induced impairment of memory retention through histamine H(1) receptors and an alpha(2)-adrenoceptor mechanism may be involved in the histamine response.

Comparing the effects of ginger and glibenclamide on dihydroxybenzoic metabolites produced in stz-induced diabetic rats.

BACKGROUND: The aim of the present study was to investigate the effect of ginger and glibenclamide on oxidative stress markers. Oxidative stress is caused by an unbalance between a relative overload of oxidants and depletion of antioxidants, as implicated in the pathogenesis of several chronic diseases, including atherosclerosis and diabetes mellitus. Regarding the role of oxidative stress in the pathogenesis of diabetes mellitus, we investigated the effect of ginger and glibenclamide in diabetic rats induced bystreptozocin (STZ). OBJECTIVES: This study assessed the effects of ginger and glibenclamide on dihydroxybenzoic acid metabolites in diabetic rats. MATERIALS AND METHODS: In this study 30 Wistar strain male rats were divided into five groups: Group 1: Normal control receiving normal saline (0.9 0/0), Group 2: control DMSO (Dimethyl sulfoxide) (as solvent of glibenclamide), Group 3: Diabetic control receiving Streptozocin (STZ ) (50 mg/kg) ,Group 4: diabetic+ Ginger Extract: this group received ginger ethanolic extract (200 mg/kg) via IP (Intraperitoneally) injection for 30 days, and Group 5 diabetic rats received glibenclamide (0.5 m/kg). Production of hydroxyl radicals was examined in the diabetic rats induced by streptozocin. Hydroxyl radicals were generated in plasma of the hyperglycemic rats, and were quantitatively assayed by trapping hydroxyl radicals with salicylic acid so as to produce 2,3-and 2,5-dihydroxybenzoic acid. RESULTS: Production of hydroxyl radicals increased; therefore, by using salicylic acid, hydroxyl radicals were trapped and 2,3dihydroxybenzoic acid and 2,5dihydroxybenzoic acid metabolites were formed then measured by HPLC and spectrophotometer. Rats receiving ginger extract and glibenclamide showed decreased level of metabolites compared to the diabetic controls (P <0/001). This means that antioxidants act as scavenger of free radicals. CONCLUSIONS: Comparative effect of ginger and glibenclamide also showed that glibenclamide has antioxidant effect as a scavenger of free radical, but ginger is more capable of eliminating them.

Maternal zinc intake of Wistar rats has a protective effect in the alloxan-induced diabetic offspring.

Zinc has a role in the synthesis, storage, and secretion of insulin, and has been suggested to be beneficial when used in the diabetic state. Effect of zinc intake in pregnant rats has been studied here on diabetized offspring. Pregnant rats were divided in two groups; the control group received normal food and water, and the experimental group received zinc sulfate during pregnancy and 3 weeks after offspring birth. Male offspring from the control (C) and experimental (E) groups were divided each in three groups: C1, fed with normal food and water; C2, diabetized with alloxan; C3, received zinc sulfate; E1, fed with normal food and water; E2, diabetized with alloxan; and E3, receiving zinc sulfate. After 30 days, the histological changes of pancreatic tissues were investigated by light microscopy. Body weight, blood glucose, serum insulin levels, food intake, water intake, and urine quantity were also compared between the groups. Water intake and urine quantity were decreased significantly (p < 0.01 and p < 0.001) in E2 (experimental diabetic group) in comparison with C2 (control diabetic group), but there was no significant difference in the body weight in C2 in comparison with E2, while blood glucose was decreased significantly (p < 0.001) and blood insulin level was increased significantly (p < 0.01) in E2 in comparison with C2. Microscopic evaluation of pancreas showed that E2 were protected against alloxan-induced beta-cell degeneration. In conclusion, this work showed that maternal zinc intake may influence subsequent deleterious effects of diabetes on alloxan-diabetized offspring.

The effects of hippocampal opioidergic and septal GABAergic system interactions on anxiety-like behavior in rats.

AIMS: Previous studies have shown that the septum and hippocampus are connected and play a key role in anxiety-related behavior. In the present study, the effects of the interactions between the opioidergic system in the dorsal hippocampus (CA1) and the GABAergic system in the medial septum on anxiety in male Wistar rats were investigated. MAIN METHODS: An elevated plus maze was used to study the effects of anxiogenic and anxiolytic drugs in rodents. Male Wistar rats were used for this test. We injected morphine (2.5, 5.0, and 7.5 µg/rat) into the CA1 and GABA(A) agonist muscimol (2.5, 5.0, and 10.0 ng/rat) into the intra-medial septum (MS). Conversely, we detected the microinjection of bicuculline, a GABA(A) antagonist (10, 20, and 30 ng/rat), into the MS. OAT%, OAE% and locomotor activity were determined by this behavioral test. KEY FINDINGS: We found that the simultaneous administration of intra-CA1 morphine (2.5 µg/rat) and intra-MS muscimol (2.5 ng/rat) increased the magnitude of anxiolysis. On the other hand, simultaneous administration of intra-CA1 morphine (7.5 µg/rat) and intra-MS bicuculline decreased the anxiolytic effect. SIGNIFICANCE: In conclusion, our data suggest that the opioidergic system in the CA1 is involved in anxiety-related behavior and influences the GABAergic system within the MS. In addition, we observed that the interactions between the opioidergic and GABAergic systems within the septohippocampus increased anxiety-related behavior compared to stimulation of these receptor systems independently.