下丘脑孤啡肽参与电针对去卵巢大鼠LH释放的影响

Hypothalamic Orphanin FQ Participated in the Regulation of Electroacupuncture on LH Release in Ovariectomized Rats

目的:在去卵巢大鼠模型上,观察下丘脑孤啡肽及其受体是否参与电针对黄体生成素(LH)超常释放的影响,进一步探讨电针作用的神经内分泌机制。方法:雌性SD大鼠随机分为假手术组、假手术加电针组、去卵巢组和去卵巢加电针组。采用放射免疫法(RIA)测定各组动物血清LH水平,免疫组化、Westernblot和RT-PCR观察电针对去卵巢大鼠下丘脑孤啡肽及其受体蛋白和mRNA表达的影响。结果:大鼠去卵巢后,下丘脑孤啡肽及其受体的表达均明显降低。电针处理后,去卵巢大鼠LH超常分泌受到明显抑制;基底下丘脑的内侧视前区、腹内侧核的孤啡肽免疫阳性神经元数目明显增加,正中隆起孤啡肽免疫阳性纤维也明显增加;基底下丘脑的孤啡肽mRNA表达上调。结论:①下丘脑孤啡肽及其受体可能参与LH分泌的调节;②孤啡肽可能参与了电针调整去卵巢大鼠下丘脑-垂体-卵巢轴异常功能的神经内分泌机制。

Objective： To investigate the effect of ovariectomy and electroaoupuncture （EA） on LH release and its possible neuroendocrinological mechanism. Methods： Twenty-four female SD rats were randomly and evenly divided into sham-operation （control） group, sham operation ＋EA group, ovariectomized （OVX, model） group and OVX ＋EA group. EA （2-3 Hz, 1- 2 mA, continuous waves） was applied to “Guanyuan”（CV 4）, “Zhongji”（CV 3）, bilateral “Zigong”（TE 6） and unilateral “Sanyinjiao”（SP 6） for 30 min, once per day, 3 days altogether. The techniques of radioimmunoassay （RIA）, immunohistochemistry, Western blot and reversed transcription-polymerase chain reaction （RT-PCR） were used for assay of serum luteinizing hormone （LH） level, expression of hypothalamic orphanin （O）FQ mRNA, ORL1 receptor （ORL1） mRNA and protein. Results： Compared with control group, serum LH level increased abnormally in OVX group （ P〈 0.05） ; and comparison between OVX and OVX＋ EA groups showed that serum LH of the later group was significantly lower than that of the former group （ P〈 0.05）. No significant difference was found between EA and OVX ＋ EA groups in serum LH levels （P 〉 0.05）. Immunohistochemical results indicated that the number of OFQ immunoreaction （IR）-positive cells of hypothalamic ventromedial nucleus （VMN） and medial preoptic area （MPOA） and the relative optical density （OD） value of OFQ IR-positive fibers of the median eminence in OVX group decreased considerably （P〈0.05） ; the number of OFQ IR-positive cells and OD value of IR-positive fibers of OVX＋ EA group were significently higher than those of OVX group （ P 〈 0.05）. Results of RT-PCR and Western blot examination showed that OD values of OFQ and ORL1 mRNA and ORL1 receptor protein of hypothalamic basal part in OVX group were significantly lower than those in control group （P〈0.05） ; while OD value of OFQ mRNA in OVX＋ EA group was significantly higher than that of OVX group （ P〈 0.05）. No significant differences were found between control and EA groups in OD values of OFQ mRNA and ORL1 mRNA and ORL1 receptor protein, and between OVX and OVX＋ EA groups in OD values of ORL1 mRNA and ORL1 receptor protein. Conclusion： Hypothalamic OFQ and ORL1 receptor may play a role in the regulation of LH release, and OFQ is involved in the normalization effect of EA on subnormal function of hypothalarnus-pituitary-ovary axis in ovariectornized rats.