Basic Research
Copyright ©The Author(s) 2004. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Jun 15, 2004; 10(12): 1780-1784
Published online Jun 15, 2004. doi: 10.3748/wjg.v10.i12.1780
Expression of gonadotropin-releasing hormone receptor and effect of gonadotropin-releasing hormone analogue on proliferation of cultured gastric smooth muscle cells of rats
Lei Chen, Hong-Xuan He, Xu-De Sun, Jing Zhao, Li-Hong Liu, Wei-Quan Huang, Rong-Qing Zhang
Lei Chen, Hong-Xuan He, Rong-Qing Zhang, Department of Biological Science and Biotechnology, Tsinghua University, Beijing, 100084, China
Xu-De Sun, Department of Anaesthesiology, Tangdu Hospital, the Fourth Military Medical University, Xi’an, 710038, Shaanxi Province, China
Lei Chen, Jing Zhao, Li-Hong Liu, Wei-Quan Huang, Faculty of Basic Medicine, the Fourth Military Medical University, Xi’an, 710032, Shaanxi Province, China
Author contributions: All authors contributed equally to the work.
Supported by the Natural Science Foundation of China, No. 39770388
Correspondence to: Professor Rong-Qing Zhang, Institute of Marine Biotechnology, Department of Biological Science and Biotechnology, Tsinghua University, Beijing, 100084, China. rqzhang@mail.tsinghua.edu.cn
Telephone: +86-10-62772899 Fax: +86-10-62772899
Received: December 19, 2003
Revised: January 23, 2004
Accepted: February 1, 2004
Published online: June 15, 2004
Abstract

AIM: To investigate the expression of gonadotropin-releasing hormone (GnRH) receptor and the effects of GnRH analog (alarelin) on proliferation of cultured gastric smooth muscle cells (GSMC) of rats.

METHODS: Immunohistochemical ABC methods and in situ hybridization methods were used to dectect protein and mRNA expression of GnRH receptor in GSMC, respectively. Techniques of cell culture, OD value of MTT test, measure of 3H-TdR incorporation, average fluorescent values of proliferating cell nuclear antigen (PCNA) and flow cytometric DNA analysis were used in the experiment.

RESULTS: The cultured GSMC of rats showed immunoreactivity for GnRH receptor; positive staining was located in cytoplasm. GnRH receptor mRNA hybridized signals were also detected in cytoplasm. When alarelin (10-9, 10-7, 10-5 mol/L) was administered into the medium and incubated for 24 h, OD value of MTT, 3H-TdR incorporation and average fluorescent values of PCNA all decreased significantly as compared with the control group (P < 0.05). The maximum inhibitory effect on cell proliferation was achieved a concentration of 10-5 mol/L and it acted in a dose-dependent manner. Flow cytometric DNA analysis revealed that alarelin could significantly enhance ratio of G1 phase and decrease ratio of S phase of GSMC of rats (P < 0.05).The maximum inhibitory effect on ratio of S phase was at the concentration of 10-5 mol/L and also acted in a dose-dependent manner.

CONCLUSION: Our data suggest that GnRH receptor can be expressed by GSMC of rats. GnRH analogue can directly inhibit proliferation and DNA synthesis of rat GSMC through GnRH receptors.

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