Effects of 17β-estradiol on threshold of rat neuropathic pain / 重庆医学

ABSTRACT

Objective To investigate the effect of 17β-estradiol on the pain threshold in neuropathic rats.Methods Fifty fe-male SD rats were divided into five groups by adopting the random number table method,the sham operation group(separating and exposing the left sciatic nerve without ligation and giving the saline injection),the other four groups were established as chronic compression injury(CCI)model of sciatic nerveCCI group(saline injection),estradiol group(17β-estradiol injection),antagonist group(AP-5 injection)and composite group(17β-estradiol and AP-5 injection),10 cases in each group.The rat mechanical pain threshold value was examined by adopting the paw withdrawal mechanical threshold(PWMT),the rat thermal threshold was exam-ined by adopting the paw withdrawal thermal latency(PWTL),and the expression of NMDAR1 protein was determined by immuno-histochemistry and Western blot.Results Compared with the sham operation group,PWM T in the CCI group and estradiol group was decreased(P<0.05)and PWTL was shortened(P< 0.05),while the expression of NMDAR1 protein was significantly in-creased(P<0.05).Compared with the CCI group,PWMT in the estradiol group was decreased(P<0.05)and PWTL was short-ened(P<0.05),while the expression of NMDAR1 protein was significantly increased(P<0.05).Conclusion 17β-estradiol can de-crease the pain threshold of the neuropathic pain rats by increasing the NMDAR1 expression.