Role of morphine preconditioning and nitric oxide following brain ischemia reperfusion injury in mice

Objective(s): Morphine dependence (MD) potently protects heart against ischemia reperfusion (IR) injury through specific signaling mechanisms, which are different from the pathways involved in acute morphine treatment or classical preconditioning. Since opioid receptor density changes post cerebral ischemia strongly correlated with brain histological damage, in the present study, we tried to elucidate the possible role of opioid receptors in IR injury among morphine-dependent mice. Materials and Methods: Accordingly, incremental doses (10 mg/kg/day to 30 mg/kg/day) of morphine sulphate were subcutaneously administered for 5 days before global brain ischemia induction through bilateral common carotid artery occlusion. Animals were received naloxone (5 mg/kg) or L-NAME (20 mg/kg) 30 min after the last morphine dose. Twenty four hr after the ischemia induction, Retention trial of passive avoidance test and western blot analysis were done. histological analysis (TUNEL and NISSL staining) performed 72 hr after ischemia. Results: MD improved post ischemia memory performance (P<0.01) and neuronal survival (P<0.001) and decreased apoptosis (P<0.05) in region I of hippocampus (CA1 region) in mouse. Treatment with naloxone or L-NAME abolished all MD aforementioned effects. Conclusion: Results of the present study suggested that opioid receptors activation in the early hr post ischemia is crucial for MD-induced hippocampus tolerance against IR injury. Opioid receptor-dependent balance of NO production was another key factor in MD-induced protection. Further studies are required to determine the effect of MD on opioid receptor changes after ischemia and its correlation with MD-induced protection. © 2015, Mashhad University of Medical Sciences. All rights reserved

Effect of berberine chloride on caspase-3 dependent apoptosis and antioxidant capacity in the hippocampus of the chronic cerebral hypoperfusion rat model

Objective(s): The main goal of the current research was to examine the effects of Berberine (BBR) on apoptotic signaling and hippocampal oxidative stress induced by common carotid artery occlusion. Materials and Methods: Chronic cerebral hypoperfusion (CCH) model was created by occluding the two common carotid arteries (two-vessel occlusion 2VO) permanently. BBR (50 and 100 mg/kg/daily) was intra-gastrically administered to ischemic rats. Neuronal survival was evaluated by Nissl staining. The levels of malondialdehyde (MDA) and antioxidant enzymes, including catalase (CAT) and superoxide dismutase (SOD), along with the activities of caspase 3 were estimated in the hippocampus 2 month after treating the rats with 2VO. Results: According to findings of the present research, the BBR therapy inhibited the neurodegeneration of hippocampus. BBR also significantly decreased the amount of MDA and activity of caspase 3 in the hippocampus. Furthermore, the administration of BBR alleviated the lowered activities of SOD and CAT after 2VO surgery. Conclusion: The antioxidant and antiapoptotic properties of BBR might play important roles in improving functional outcomes and might have significant neuroprotective effects on the CCH damage. © 2019, Mashhad University of Medical Sciences. All rights reserved

Effect of berberine chloride on caspase-3 dependent apoptosis and antioxidant capacity in the hippocampus of the chronic cerebral hypoperfusion rat model

Objective(s): The main goal of the current research was to examine the effects of Berberine (BBR) on apoptotic signaling and hippocampal oxidative stress induced by common carotid artery occlusion. Materials and Methods: Chronic cerebral hypoperfusion (CCH) model was created by occluding the two common carotid arteries (two-vessel occlusion 2VO) permanently. BBR (50 and 100 mg/kg/daily) was intra-gastrically administered to ischemic rats. Neuronal survival was evaluated by Nissl staining. The levels of malondialdehyde (MDA) and antioxidant enzymes, including catalase (CAT) and superoxide dismutase (SOD), along with the activities of caspase 3 were estimated in the hippocampus 2 month after treating the rats with 2VO. Results: According to findings of the present research, the BBR therapy inhibited the neurodegeneration of hippocampus. BBR also significantly decreased the amount of MDA and activity of caspase 3 in the hippocampus. Furthermore, the administration of BBR alleviated the lowered activities of SOD and CAT after 2VO surgery. Conclusion: The antioxidant and antiapoptotic properties of BBR might play important roles in improving functional outcomes and might have significant neuroprotective effects on the CCH damage. © 2019, Mashhad University of Medical Sciences. All rights reserved

The Protective Effect of Remote Renal Preconditioning Against Hippocampal Ischemia Reperfusion Injury: Role of KATP Channels

Remote ischemic preconditioning (RIPC), which consists of several brief ischemia/reperfusion applied at the remote site of lethal ischemia reperfusion, can, through activating different mechanisms, increase the ability of the body�s endogenous protection against prolonged ischemia/reperfusion. Recent studies have shown that RIPC has neuroprotective effects, but its mechanisms are not well elucidated. The present study aimed to determine whether activation of KATP channels in remote renal preconditioning decreases hippocampus damage induced by global cerebral ischemia. RIPC was induced by ischemia of the left renal artery (IPC); 24 h later, global cerebral ischemia reperfusion (IR) was induced by common carotid arteries occlusion. 5hydroxydecanoate (5HD) and glibenclamide (Gli) were injected before of IPC. The levels of malondialdehyde (MDA) and catalase (CAT) activity were assessed in hippocampus. Terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) was assessed to detect apoptotic cells in hippocampus. RIPC inhibited apoptosis by decreasing positive TUNEL cells (P < 0.05). KATP channels blocking with 5HD and Gli markedly increased apoptosis in hippocampal cells in RIPC group (P < 0.001). RIPC decreased MDA level and increased CAT activity in ischemic hippocampus (P < 0.01). Also, 5HD and Gli inhibited the effect of RIPC on MDA level and CAT activity (P < 0.05). The present study shows that RIPC can effectively attenuate programmed cell death, increase activity of CAT, and reduce MDA levels. Blocking of KATP channels inhibited the protective effects of RIPC. © 2015, Springer Science+Business Media New York

Knocking down the DRD2 by shRNA expressing plasmids in the nucleus accumbens prevented the disrupting effect of apomorphine on prepulse inhibition in rat

Prepulse Inhibition (PPI), the objective measure of sensorimotor gating disturbance has being widely used in animal models of schizophrenia. Dopaminergic direct and indirect agonists impair PPI. However, the profile of dopaminergic receptors involved in PPI impairment by dopamine agonists is not clear. By injecting shRNA expressing plasmids against dopamine D2 receptor genes (DRD2) in the nucleus accumbens, here, we studied the effect of apomorphine on PPI in D2 down-regulated rats. Seventy two adult Wistar rats assigned randomly in nine groups, each received coding (250 and 500 ng/μl) or noncoding shRNA expressing plasmids against DRD2 in the nucleus accumbens, with or without apomorphine (0.5 mg/kg, S.C., 72 hours after treatment with plasmids). Auditory startle response and PPI were measured after apomorphine injection. Real time RT-PCR was used to measure DRD2 expression. Results showed that apomorphine significantly decreased PPI in noncoding plasmid treated rats; While, PPI did not impaired in rats pretreated with 250 and 500 ng/μl shRNA expressing plasmids. Accordingly, the expression of DRD2 mRNA in the nucleus accumbens showed 72-78 decrease in expressing plasmid treated rats. Additionally, treatment with expressing plasmids had no effect on basal PPI and/or auditory startle response. Taken together, our results demonstrated that DRD2 silencing in the nucleus accumbens can prevent PPI impairment by apomorphine. These observations suggest application of molecular techniques such as the use of shRNA against DRD2s in studies of schizophrenia pathophysiology and development of new treatments in schizophrenia