黄体酮对戊四唑致痫大鼠海马内GABA能神经元影响的形态学研究

A MORPHOLOGICAL STUDY ON THE EFFECTS OF PROGESTERONE ON GABAERGIC NEURONS IN THE HIPPOCAMPUS OF PTZ-INDUCED EPILEPTIC RATS

本实验采用免疫组织化学方法,研究了黄体酮对戊四唑(PTZ)致痫大鼠的发作情况和海马内γ-氨基丁酸(GABA)能神经元的影响,旨在从形态学角度探讨黄体酮对抗癫痫作用的可能机制。实验中采用成年去卵巢(OVX)雌性SD大鼠,随机分成空白对照、实验对照和实验给药3组。空白对照组和实验对照组经腹腔注射生理盐水(NS),实验给药组经腹腔注射黄体酮,每天一次。3 d后,空白对照组经腹腔注射NS,实验对照和实验给药组经腹腔注射PTZ致痈。注射PTZ 1 h后,灌流固定,取脑,做振动切片。取含背侧海马的脑片,ABC法免疫组化染色。图象分析计数海马齿状回门区内GABA免疫阳性细胞数。结果:(1)实验给药组大鼠均未出现癫痫发作;(2)三组间齿状回门区内GABA免疫阳性细胞数存在显著差异(P<0.01);实验给药组的GABA免疫阳性细胞数明显增加(P<0.05)。结果显示,黄体酮可对抗PTZ致痫的行为发作和门区GABA能中间神经元的损伤,并提示黄体酮可能具有增强GABA能系统的作用。

The present experiment investigated the effects of progesterone on pentylenetetrazol (PTZ)-induced seizures and γ aminobutyric acid (GABA) neurons of the hippocampus in ovariectomized (OVX) female rats. The purpose is to elucidate the mechanism of the effects of progesterone against seizure susceptibility. OVX adult female Sprague-Dawley rats were divided randomly into NS control, experimental control and experimental groups. The OVX rats in experimental group were injected with progesterone intraperitoneally once per day for three days. Simultaneously, the OVX rats in NS control and experimental control groups were injected with matched doses of NS. On the third day, the OVX rats in experimental control and experimental groups were treated with PTZ to induce seizures. Simultaneously, rats in NS control group were given matched doses of NS. One hour after injection of PTZ, the OVX rats were perfused and fixed. The brains were removed and sectioned by a vibratome sheer. The sections with dorsal hippocampus were stained by ABC immunohistochemical method- GABA-positive neurons in the hilus of dentate gyrus were counted by the computer image analysis software. The results showed that; (1) Pretreatment with progesterone could completely protect OVX rats against PTZ-induced seizures; (2)The number of GABA-positive neurons increased significantly in hilus of the rats injected with progesterone (P<0. 05). These results suggest that progesterone significantly raised the threshold of PTZ-induced seizures. In addition, progesterone might play a role in enhancing the effects of GABA system in female rats.