敲除缝隙连接蛋白Cx 43基因对针刺抑制小鼠内脏痛反应的影响

目的:探讨缝隙连接蛋白43(Cx43)影响针刺镇痛作用的可能中枢和外周机制。方法:将野生型(WT)和Cx43基因敲除杂合子(HT)小鼠随机分为6组:WT空白对照组、WT模型组、WT针刺组、HT空白对照组、HT模型组和HT针刺组,每组18只,腹腔注射0.6%醋酸(0.1 mL/10 g)制造内脏痛模型。针刺"中脘"、双侧"足三里"穴,每5 min捻针30 s,共30 min。比较各组小鼠首次扭体潜伏期、20 min扭体反应次数。放射免疫法检测下丘脑β-内啡肽(β-EP)和血清前列腺素E2(PGE2)含量。结果:HT与WT空白对照组小鼠首次扭体潜伏期、20 min扭体反应次数、下丘脑组织β-EP和血清PGE2含量差异均无显著性意义(P>0.05)。与对照组比较,HT和WT内脏痛模型组小鼠首次扭体潜伏期明显缩短(P<0.01),20 min扭体反应次数显著增加(P<0.01),下丘脑β-EP和血清PGE2含量明显升高(P<0.05);两模型组间上述各指标差异均无显著性意义(P>0.05)。与模型组比较,WT针刺组小鼠首次扭体潜伏期明显延长(P<0.01),扭体反应次数明显减少(P<0.01),下丘脑组织β-EP含量显著升高(P<0.05),血清PGE2含量显著降低(P<0.05)。HT针刺组小鼠各项指标与模型组比较差异无显著性意义(P>0.05)。HT针刺组首次扭体潜伏期、下丘脑β-EP含量明显低于WT针刺组(P<0.05),而HT针刺组扭体反应次数和血清PGE2含量明显高于WT针刺组(P<0.05)。结论:针刺缓解腹腔内脏痛的作用可能是通过促使中枢和外周镇痛物质β-EP增加、致痛物质PGE2减少而实现的。Cx43与针刺镇痛效应有着密切联系。

Influence of Connexin 43 Gene Knockout on the Analgesic Effect of Acupuncture in Visceral Pain Mice

OBJECTIVE: To explore the possible central and peripheral mechanisms of connexin 43 gene knockout in acupuncture analgesia. METHODS: Fifty-four wide type (WT) mice and 54 connexin 43 gene knockout (heterozygote, HT) mice were randomly divided into WT control group, WT model group, WT acupuncture group, HT control group, HT model group and HT acupuncture group (n = 18/group). Visceral pain model was established by intraperitoneal injection of 0.6% acetic acid (0. 1 mL/10 g). "Zhongwan" (CV 12) and bilateral "Zusanli" (ST 36) were punctured with filiform needles and stimulated for 30 min by manipulating the needle for 30 s every 5 min. The latency and the number of body-writhing response were observed and the contents of beta-endorphin (beta-EP) in hypothalamus and serum prostaglandin E2 (PGE2) were detected with radioimmunoassay (RIA). RESULTS: There was no significant difference in the latency and the number of body-writhing response, and contents of hypothalamic beta-EP and serum PGE2 between HT and WT control groups (P > 0.05). Compared with the corresponding control groups, the latency of body-writhing in WT model and HT model groups shortened significantly and the number of body- writhing increased considerably in two model groups (P < 0.01). While in comparison with WT model group, the latency of body-writhing prolonged significantly and the number of body-writhing decreased apparently in WT acupuncture group (P < 0.01); but no marked differences were found between HT model and HT acupuncture groups in these two indexes (P > 0.05). Compared with the corresponding control groups, the contents of both beta-EP and PGE2 increased obviously in WT model and HT model groups (P < 0.05). In comparison with WT model group, beta-EP levels in WT acupuncture group increased further significantly (P < 0.05), and serum PGE2 in WT acupuncture group decreased obviously (P < 0.05); but no significant changes were found between HT model and HT acupuncture groups in beta-EP and PGE2 levels (P > 0.05). CONCLUSION: Acupuncture has a marked antinociceptive effect in WT mice with visceral pain, which may be related to its effects in increasing hypothalamic beta-EP and decreasing serum PGE2; while in connexin 43 gene knockout mice, all the above-mentioned effects of acupuncture are eliminated, indicating an important role of connexin 43 in the analgesic effect of acupuncture.