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Effects of tetramethylpyrazine on trigeminal neuralgia induced by chronic constriction injury of infraorbital nerve in rats

TAN Meng-Xia, XIONG Wei, HE Ling-Kun, YANG Guo, HUANG Li-Ping, SHEN Yu-Lin, LIANG Shang-Dong, GAO Yun

Department of Physiology, Basic Medical College of Nanchang University, Nanchang 330006, China； Department of Preventive Dentistry, The Affiliated Stomatological Hospital of Nanchang University, Nanchang 330019, China； Grade 2013 of Queen Mary College, Nanchang University, Nanchang 330031, China

Abstract

Trigeminal neuralgia (TN) is a kind of recurrent transient and severe pain that is limited to the trigeminal nerve in one or more branches. The clinical incidence of TN is high, which seriously affects the quality of life of the patients and is difficult to cure. The present study investigated the effects of tetramethylpyrazine (TMP) on TN induced by chronic constriction injury of the infraorbital nerve (ION-CCI) in rats. Adult male Sprague-Dawley rats were randomly assigned to four groups: sham, sham treated with TMP (Sham+TMP), TN model (TN), and TN treated with TMP (TN+TMP). The rat TN model was established by ION-CCI and TMP (50 mg/kg) was injected intraperitoneally once a day for 2 weeks after operation. The mechanical response threshold was tested by the electronic von Frey filaments. The expression of CGRP in the trigeminal ganglia (TGs) of rats on the operative side was detected by RT-PCR, immunohistochemical staining and Western blot. In 15 days after operation, TN group showed a robust decrease in mechanical response threshold as compared with sham group. From day 9 to day 15 after operation, TMP treatment significantly suppressed the TN-induced mechanical hyperalgesia (P < 0.05). On day 15 after operation, RT-PCR, immunohistochemical staining and Western blot analysis showed an obvious increase in expression level of CGRP in TGs of TN group compared with sham group, which was downregulated by TMP treatment (P < 0.05). These results suggested that TMP might have a therapeutic potential for the treatment of TN through regulating CGRP expression in the TGs.

Key words: Calcitonin gene-related peptide; trigeminal neuralgia ; tetramethylpyrazine ; trigeminal ganglion

Received: 2016-07-20　　Accepted: 2016-09-30

Corresponding author: 高云　　E-mail: gaoyun90@163.com

Citing This Article：

TAN Meng-Xia, XIONG Wei, HE Ling-Kun, YANG Guo, HUANG Li-Ping, SHEN Yu-Lin, LIANG Shang-Dong, GAO Yun. Effects of tetramethylpyrazine on trigeminal neuralgia induced by chronic constriction injury of infraorbital nerve in rats. Acta Physiol Sin 2017; 69 (1): 89-95 (in Chinese with English abstract).