Research on acquisition of ischemic-tolerance-like phenomenon intermediated by opioid receptors

本研究通过短时间前脑缺血，探讨阿片受体在缺血耐受样现象中的作用。雄性沙土鼠采用双侧颈总动脉阻断后模型。实验分为6组：缺血5 min再灌注7 d组（Isch组），缺血2 min再灌注3d再灌注5 min再灌注7 d组（PC组），纳洛酮3 mg/kg iv。随后同PC组（NX 1组），iv纳洛酮0.03mg/kg。随后为PC组（NX 2组）和对照组。缺血5 min后再灌注，所有沙土鼠用甲醛灌注，并用HE染色评价脑样品中海马神经元的损伤。对照组海马CA 1 -2区无明显损伤。Isch组神经元损伤严重，可见空泡变性、核固缩。但PC组海马神经元损伤明显好于其他各组。NX 1、NX 2组海马CA 1 -2区神经元的损伤程度再次低于对照组，M组海马神经元损伤程度也低于对照组。这些发现表明，阿片受体的参与，可能比其他？-受体在缺血耐受现象中的作用。

In this study, we examined the role of opioid receptors in ischemic-tolerance-like phenomenon by short period of forebrain ischemia. In male gerbils used bilateral common carotid afrter-occlusion model. Animals were divided into six groups : 5 min ischemia and 7 days reperfusion (Isch group), 2 min ischemia and 3 days reperfusion followed by 5 min ischemia and 7 days reperfusion (PC group), naloxone 3 mg/kg iv. followed by the sam condition as PC group (NX1 group), naloxone 0.03 mg/kg iv. followed by the same condition of PC group (NX2 group), and control group. After reperfusion after 5 min ischemia, all gerbils were perfused with formaldehyde, and the brain samples were evaluated for neuronal damage in the hippocampus with HE-staining. In control group, the CA1-2 region of hippocampus showed no damage. In Isch group, they were severely damaged revealing vacuolation and pyknosis of neurons. However, the neuronal injury in hippocampus was significantly better in PC group compared to the other groups. In NX1 and NX2 groups, the CA1-2 regions were again worse than control group, and the neurons in hippocampus were also worse in M group. These findings suggest that the involvement of opioid receptors, possibly other than ?-receptors in the phenomenon of ischemic tolerance.