Objectives: To investigate the potential role of GABAB Receptors (GABABRs) involved in the effect\nof Nourishing ââ?¬Å?Yinââ?¬Â-Removing ââ?¬Å?Fireââ?¬Â Chinese herb mixture (TCM) treatment on precocious puberty.\nMethods: Female Sprague-Dawley rats were randomly divided into four groups: normal (N),\ncentral precocious puberty (CPP) model (M), CPP fed with normal saline (S) and CPP fed with Nourishing\nââ?¬Å?Yinââ?¬Â-Removing ââ?¬Å?Fireââ?¬Â Chinese herb mixture (TCM). Rats of postnatal day 5 were given a\nsingle subcutaneous injection of 240 \n \n\n\n \n\n \n \ngroups were continuously administered with saline or nourishing ââ?¬Å?Yinââ?¬Â-removing ââ?¬Å?Fireââ?¬Â Chinese\nherb mixture since postnatal day 15. The expression of GABABRs was detected by means of realtime\nPCR and immunohistochemistry. Results: The expression of hypothalamic GnRH mRNA in M\nwas significantly increased on the day of pre-puberty when compared with that of N (P < 0.01). On\nthe day of onset-puberty, LH levels were higher in M than those in N (P < 0.01), while the serum E2\nand LH levels of TCM decreased when compared with those of M (P < 0.05). On the day of\npre-puberty, the number of GABAB1 receptor (GABABR1) immunoreactive cells in the arcuate nucleus\n(ARN) was decreased in M when compared with that of N (P < 0.05) and increased in TCM\ncompared with that of M (P < 0.05); simultaneously, the expression of GABABR1 mRNA in hypothalamus\nwas significantly decreased in M when compared with that of N (P < 0.01) and increased\nin TCM compared with that of M (P < 0.01). On the day of onset-puberty, the number of GABABR1\nimmunoreactive cells in medial septum (MS) was decreased in M compared with that in N (P <\n0.05) and increased in TCM comparing with that of M (P < 0.05); meanwhile, the mRNA expression\nof GABABR1 in hypothalamus was decreased in M compared with that in N (P < 0.05), while the numbers of GABAB2 receptor (GABABR2) immunoreactive cells in the ARN, MS and diagnonal band\nof broca (DBB) were decreased in M when compared with those of N (P < 0.05) and increased in\nTCM compared with those of M (P < 0.05) on the day of onset-puberty. At the same time, the mRNA\nexpression of GABABR2 was significantly decreased in M compared with that of N (P < 0.01). Conclusions:\nThese results indicated that the GABABRs might involve in the curative effect of Nourishing\nââ?¬Å?Yinââ?¬Â-Removing ââ?¬Å?Fireââ?¬Â Chinese herbal mixture on CPP rats.
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