去卵巢大鼠HPOA功能自然代偿过程中GnRH的异位表达及电针处理对其的影响

Ectopic Expression of GnRH during Natural Compensation of HPOA Function and the effect of Electroacupuncture on It in Ovariectomized Rats

目的在切除卵巢后的“围绝经期”大鼠模型上,探讨下丘脑-垂体-卵巢轴（hypothalamus-pituitary-ovary axis,HPOA）功能低下时,机体的自然代偿过程中,下丘脑室旁核（paraventricular nucleus,PVN）促性腺激素释放激素（gonadotropin-releasing hormone,GnRH）的异位表达及电针处理对代偿过程的影响。方法动物分为正常组（INT）、去卵巢组（OVX）、自然代偿组（OVX3M组、OVX4M组、OVX5M组、OVX6M组）以及去卵巢加电针组（OVX＋EA）。用HE染色的方法观察大鼠阴道脱落细胞的变化,用放射免疫分析（radioimmunoassay,RIA）的方法观察外周血雌二醇水平的变化,用免疫组织化学的方法观察GnRH在PVN的表达,以及免疫荧光双标结合激光共聚焦显微镜的观察方法观察GnRH与促肾上腺激素释放激素（corticor-tropin-releasing hormone,CRH）在PVN的共存。结果去卵巢4个月时大鼠阴道涂片出现成熟脱落细胞;4个月时血E2水平明显升高,6个月时几乎稳定在正常水平的一半左右;正常组与去卵巢组大鼠PVN未发现有GnRH免疫阳性物质的表达;去卵巢加电针组以及切除卵巢后3～6个月自然代偿组的大鼠在PVN都分别有GnRH的表达;GnRH与CRH在PVN共存于同一个神经元中。结论GnRH在PVN中的异位表达,并与CRH共存于同一神经元中,可能是机体对HPOA功能异常的自然代偿;而电针处理可能提前启动了这一自然代偿机制,从而发挥对大鼠因去卵巢术而引起的HPOA功能异常的调整作用。

Objective To explore the ectopic expression of gonadotropin releasing hormone（GnRH） in paraventricular nucleus（PVN） during the natural compensation of the body for hypothalamus-pituitary-ovarian axis（HPOA） hypofunction and the effect of electroacupuncture on it in an ovariectomized rat model of periclimacteric.Methods The animals were allocated to normal（INT）,ovariectomy（OVX）,natural compensation（OVX3M,OVX4M,OVX5M and OVX6M） and ovariectomy plus electroacupuncture（OVX＋EA） groups.Rat exfoliated vaginal cells were examined by HE staining.Peripheral blood estradiol was measured by radioimmunoassay（RIA）.The expression of GnRH in PVN was examined by immunohistochemistry.The coexistence of GnRH and corticotrophin releasing hormone（CRH） in PVN was examined by immunofluorescent double-labeling histochemistry under a laser confocal scanning microscope.Results Rat vaginal smear showed mature exfoliative cells at 4 months after ovariectomy.Blood E_2 level significantly rose at 4 months and stabilized at almost half of normal at 6 months.The expression of GnRH immunopositive substance in PVN was not found in the normal and ovariectomy groups of rats.The expression of GnRH in PVN and the coexistence of GnRH and CRH in the same neuron of PVN were found in both ovariectomy plus electroacupuncture and natural compensation（at 3-6 months after ovariectomy） groups of rats.Conclusion The ectopic expression of GnRH in PVN and its coexistence with CRH in the same neuron of PVN may be the natural compensation of the body for HPOA dysfunction.Electroacupuncture may start the natural compensation in advance to produce a regulative effect on rat HPOA dysfunction due to ovariectomy.