Neuronal protection of progesterone against ischemic brain injury and underlying molecular mechanisms / 中华神经科杂志

ABSTRACT

Objective To investigate the effect of progesterone pretreatment of focal cerebral ischemic and reperfusion injury (fCIRI) and underlying molecular mechanisms.Methods A single intraperitoneal injection of progesterone (8 mg/kg) given 1 h,48 h and 96 h before fCIRI was established in male Sprague-Dawley rats.The number of survival of neurons in hippocampal CA1 region of the ischemiaside,as well as spatial memory function,was detected on days 3-8 after fCIRI.Extracellular-signalregulated kinase 1/2 phosphorylation (p-ERK1/2) and nuclear translocation of p-ERK1/2 in hippocampal CA1 region were examined using western blot.Results The number of survival of neuronal cells was significantly increased in ischemic groups treated with progesterone at 1 h and 48 h pre-fCIRI (164.3 ± 11.0,218.5 ± 9.1 and 142.7 ± 12.1,F =29.4,P ＜ 0.01) compared with fCIRI group treated with vehicle.Likewise,the escape-latency to reach the hidden-platform recorded in day 5 of Morris water maze test was reduced markedly in fCIRI-treatment groups compared with the vehicle group(10.3 ± 11.1,19.2 ±9.6 and 32.4 ± 14.3 ;F =35.8,P ＜0.01).The level of p-ERK1/2 was elevated notably during 24 h to 48 h postprogesterone by western blot,while restored to the baseline at 96 h post-progesterone.Improved nuclear translocation of p-ERK1/2 was observed from 2 h to 48 h post-progesterone.The progesterone receptor antagonist RU486 blocked the exaltation of either intracellular level or nuclear translocation of p-ERK1/2,which was induced by progesterone.Conclusions The pretreatment with progesterone exerts a neuroprotective effect against the ischemia-induced neuronal death and ameliorates the deficits in spatial memory through enhancing the activation of ERK1/2.The neuroprotection derived from pretreatment with progesterone achieves a time window of not less than 48 h,which is progesterone receptor-mediated ERK1/2 signaling pathway-dependent.