nNOS expression of hippocampal neurons in aged rats after brain ischemia/reperfusion and its role in DND development / 中华创伤杂志(英文版)

ABSTRACT

<p><b>OBJECTIVE</b>To study the role of neuronal nitric oxide synthase (nNOS) in aged rats' hippocampal delayed neuronal death (DND) following brain ischemia.</p><p><b>METHODS</b>Models of incomplete brain ischemia were induced by clipping common carotid artery. A total of 46 aged SD rats were divided into 8 groups normal control group (Group A, n=5), sham-operation group (Group B, n=5), reperfusion 1, 6, 12, 24, 48, and 96 hours groups after brain ischemia for 30 minutes (Group C, D, E, F, G, and H, n=6/group). The expression of nNOS was examined by immunohistochemistry and neuronal ultrastructural changes were observed by the transmission electron microscopy (TEM) at different time points after reperfusion.</p><p><b>RESULTS</b>Immunohistochemistry showed that nNOS expression in the hippocampal neurons was high in Group E, low expression in Group D, moderate expression in Group F and G. There was nearly no expression of nNOS in Group A, B, C, and H. Ultrastructure of hippocampal neurons was damaged more severely in reperfusion over 24 hours groups.</p><p><b>CONCLUSIONS</b>Nitric oxide (NO) may be one of the important factors in inducing DND after ischemia/reperfusion.</p>