脑内催乳素释放肽参与电针对围绝经期综合征大鼠下丘脑-垂体-卵巢轴异常功能的调整

Prolactin Releasing Peptide Participates in the Effect of Electroacupuncture in Normalizing Functions of Hypothalamus-pituitary-ovary Axis in Ovariectomized Rats

目的:在围绝经期大鼠模型上,研究脑内催乳素释放肽(prolactin releasing peptide,PrRP)在电针调整下丘脑-垂体-卵巢轴(hypothalamus-pituitary-ovary axis,HPOA)异常功能中的作用,以进一步探讨针刺治疗妇女围绝经期综合征的神经内分泌机制。方法:采用切除双侧卵巢的大鼠围绝经期模型(HPOA功能异常模型),随机分为去卵巢组(OVX)、去卵巢电针组(OVX+EA);再用正常SD大鼠作为对照,分成正常组(INT)和正常电针组(INT+EA)。OVX+EA和INT+EA组接受“中极”“关元”和双侧“子宫”、单侧“三阴交”电针处理,每日1次,每次30 min,连续3 d。用放射免疫法测定外周血的雌二醇(E2)和黄体生成素(LH)含量;并用免疫组织化学法和实时定量聚合酶链反应(Real-time PCR)方法观察延髓和下丘脑PrRP蛋白及mRNA的表达。结果:OVX组的延髓孤束核(NTS)和腹外侧网状核(VLRN)免疫阳性细胞数、终纹床核(BST)阳性纤维相对光密度、延髓和下丘脑PrRP mRNA含量显著降低(P<0.01)。OVX+EA组延髓的PrRP mRNA含量比OVX组显著增加(P<0.01);同时,各个核团的PrRP免疫阳性物质均增加(P<0.01或P<0.05);OVX+EA组血清E2水平比OVX组升高(P<0.05),而LH水平却降低(P<0.05)。但INT+EA组与INT组相比无明显的变化。结论:电针效应具有多环节、多靶点的特点。PrRP作为一种新的神经肽或神经激素,参与了电针调整HPOA功能异常的作用。这可能是电针治疗妇女围绝经期综合征的神经内分泌机制之一。

Objective： To investigate the effect of electroacupuncture （EA） on dysfunction of hypothalamus-pituitary-ovary axis （HPOA） in ovariectomized （OVX） rats so as to explore the neuroendocrine mechanism of acupuncture in the treatment of woman perimenopausal syndrome, Methods： Forty-eight female SD rats （180-200 g） were randomized into OVX, OVX＋EA, normal control （NC） and EA groups with 12 cases （6 cases used for irnrnunohistochemical study and the other 6 for real-time PCR） in each group, EA （3 Hz, 2 mA） was applied to “Guanyuan”（RN 4）, “Zhongji”（RN 3）, “Sanyinjiao”（SP 6） and bilateral “Zigong”（EX-CA 1） for 30 min, once daily and continuously for 3 days, Radioimrnunoassay （RIA） was used to detect blood luteinizing hormone （LH） and estrin （E）2 contents, and real-time reversed transcription polymerase chain reaction （RT-PCR） and irnmunohistochemistry were utilized for assaying expression of prolactin-releasing peptide （PrRP） and PrRP mRNA in the medulla oblongata and hypothalamus. Results： Comparison of NC, EA, OVX and OVX＋ EA groups showed that serum E2 contents of OVX and OVX＋ EA groups were significantly lower than that of NC group, while serum LH contents of OVX and OVX＋ EA groups significantly higher than that of NC group （P〈0,01, 0,05）, and no significant differences were found between NC and EA groups in these two indexes （ P 〉0.05）. Compared with OVX group, serum LH level was markedly lower and serum E2 level markedly higher in OVX＋ EA group （ P〈 0.05）. In comparison with NO group, the ntrnber of PrRP irTnlunoreaction （PrRP-ir） positive neurons in nucleus tractus solitarii （NTS） and ventral lateral reticular nucleus （VLRN） and the relative optical density （OD） of bed nucleus of the stria terminalis （BST） in OVX group, and that in NTS in OVX ＋ EA group were markedly fewer （P 〈 0.01）, while compared with OVX group, PrRP-ir positive neurons of NTS and VLRN were significantly more and the OD value of PrRP-ir positive fibers of BST was significantly higher in OVX＋EA group （ P 〈 0.01, 0.05）. The relative contents of PrRP mRNA expression （ PrRP β- actin） of hypothalamus and medulla oblongata in OVX and OVX＋ EA groups were significantly lower than those of NC group （P〈 0.01） ; comparison between OVX and OVX＋ EA showed that the relative content of PrRP mRNA expression in the medulla oblongata in the later group was markedly higher than that of the former （ P〈 0.01 ）. No significant differences were found between NO and EA groups in the number of PrRP-ir positive neurons of NTS and VLRN, OD values of the positive fibers of BST and the relative content of PrRP mRNA expression in the hypothalamus and medulla oblongata, and between OVX and OVX＋ EA groups in the relative content of PrRP mRNA expression in the hypothalamus （P 〉 0.05）. Results indicated that in OVX rats, serum E2 level, PrRP contents in NTS, VLRN and BST, and hypothalamic PrRP expression decreased remarkably and serum LH content increased significently, while EA could reverse most of the aforementioned changes. Conclusion： PrRP, a new neuropeptide or neurohormone, participates in the effect of EA in normalizing the subnormal function of HPOA in OVX rats, which may be one of the neuroendocrine mechanisms of EA in relieving woman perimenopausal syndrome.