Effects of Sulfotanshinone Sodium Injection on neuropathic pain in rats / 中华麻醉学杂志

ABSTRACT

Objective To investigate the effects of Sulfotanshinone Sodium Injection (SSI) on neuropathic pain in rats.Methods One hundred and eight adult male Wistar rats,aged 6-8 weeks,weighing 180-220 g,were randomly divided into 3 groups (n =36 each)sham operation group (group S) ; chronic constrictive injury (CCI)group; group SSI.The animals were anesthetized with intraperitoneal 10% chloral hydrate 350 mg/kg.In groups CCI and SSI,4 ligatures were placed on the right sciatic nerve at 1 mm intervals with 4-0 silk thread according to the method described by Bennett et al.In group S,the right sciatic nerves were exposed,but not ligated.In group SSI,SSI 25 mg/kg was injected intraperitoneally once a day starting from the end of operation until one day before the animals were sacrificed,while the rats received the equal volume of normal saline (5 ml/kg) instead of SSI in groups S and CCI.Twelve animals in each group were chosen at 1 day before operation and 3,7 and 14 days after CCI (T1-4) to measure mechanical paw withdrawal threshold to yon Frey stimuli (MWT) and paw withdrawal latency to thermal nociceptive stimulus (TWL).Six rats in each group were sacrificed at T2-4 after measurement of pain threshold,and their lumbar segnents (L4-6) of the spinal cord were immediately removed for determination of Bcl2 and caspase-3 expression in spinal dorsal horn (by immune-histochemistry),and MDA content and SOD activity (by spectrophotometry) in spinal cord.Results Compared with group S,PWT was significantly decreased,PWL was shortened,the expression of Bcl-2 and caspase-3 was up-regulated,MDA content was increased and SOD activity was decreased at T2-4 in groups CCI and SSI (P ＜ 0.05).Compared with group CNP,PWT was significantly increased,PWL was prolonged,the expression of Bcl-2 was up-regulated,the expression of caspase-3 was downregulated,MDA content was decreased and SOD activity was increased at T2-4 in group SSI (P ＜ 0.05).Conclusion SSI can mitigate neuropathic pain in rats and inhibition of oxidative stress in spinal cord tissues and reduction of apoptosis in spinal dorsal horn neurons are involved in the mechanism.