Effects of tetramethylpyrazine on neuronal apoptosis in the superficial dorsal horn in a rat model of neuropathic pain

• Published in: The American journal of Chinese medicine (1979) Vol. 40; no. 6; p. 1229
• Main Authors: Leng, Yu-Fang, Gao, Xiang-Mei, Wang, Shu-Xiu, Xing, Yan-Hong
• Format: Journal Article
• Language: English
• Published: Singapore 2012
• Subjects: Animals; Apoptosis - drug effects; Caspase 3 - metabolism; Disease Models, Animal; Immunohistochemistry; In Situ Nick-End Labeling; Male; Neuralgia - pathology; Neurons - drug effects; Neurons - enzymology; Posterior Horn Cells - drug effects; Pyrazines - pharmacology; Rats
• ISSN: 0192-415X
• DOI: 10.1142/s0192415x12500917

The Bennett and Xie (1988) model of chronic constriction injury (CCI) investigated the effects of tetramethylpyrazine (TMP) on neuropathic pain-associated behaviors and neuronal apoptosis in the spinal dorsal horn. Fifty-four male rats were randomly divided into sham (group S), CCI (group C) and TMP groups (group T). Each group was divided into subgroups (n = 6 in each group) according the time of sacrifice: 3 d, 7 d and 14 d. Rat sciatic nerves were unligated (group S), or the right sciatic nerve was loosely ligated (groups C and T) to produce CCI. Mechanical withdrawal thresholds (MWTs) and thermal withdrawal latencies (TWLs) were measured, and the rats were sacrificed at different time points post-operation. The L4-L6 sections of the spinal cord were removed. Apoptotic changes were evaluated using the TUNEL method. Immunohistochemistry assessed Bcl-2 and caspase-3 expression. TMP treatment increased MWT and TWL values and Bcl-2 expression, but it reduced neuronal apoptosis and caspase-3 expression in laminae I-II of the spinal dorsal horn. These results suggested that the inhibition of neuronal apoptosis via the modulation of Bcl-2 and caspase-3 proteins in the rat spinal dorsal horn contributed to TMP-induced analgesia.