皖南地区眼镜蛇毒镇痛组分对大鼠炎性痛作用机制探讨

目的：探讨皖南地区眼镜蛇毒镇痛组分（CVAF）对大鼠炎性痛作用效应及其可能机制。方法：40只雄性SD大鼠在测定基础痛阈后随机分为4组（n=10）：正常对照组（NC组）、炎性痛模型组（CFA组）、炎性痛模型＋CVAF组（CFA＋CVAF组）和炎性痛模型＋吗啡组（CFA＋Morphine组）。随后将36只SD雄性大鼠随机分成6组（n=6）：正常对照组（NC组）、炎性痛模型组（CFA组）、炎性痛模型＋CVAF组（CFA＋CVAF组）、炎性痛模型＋阿托品＋CVAF组（CFA＋Atr＋CVAF）、炎性痛模型＋纳洛酮＋CVAF组（CFA＋Nal＋CVAF）和炎性痛模型＋L—NAME＋CVAF组（CFA＋L—NAME＋CVAF）。测定各组大鼠的热痛阈潜伏期（TWL）和机械痛阈值（MWT），制备脊髓匀浆，用于检测其中IL-1和TNF—a的表达。结果：与NC组相比，CFA组大鼠第1天开始TWL和MWT明显降低，出现热痛觉过敏和机械痛觉过敏，持续14d仍存在；CFA组大鼠脊髓匀浆IL-1和TNF—a表达均明显增高（P〈0．01）。与CFA组相比，CFA组大鼠腹腔注射CVAF后其TWL和MWT均升高，表明炎性痛大鼠热痛觉过敏和机械痛觉过敏得到改善；脊髓匀浆中IL-1、TNF—a表达显著减少（P〈0．01），显示CVAF通过抑制炎性因子的产生而发挥镇痛作用。与CFA＋CVAF组大鼠相比，L—NAME＋CVAF组大鼠明显增强了CVAF对炎性痛大鼠的镇痛作用，表现为TWL和MWT的明显升高（P〈0．01）；而CFA＋Atr＋CVAF组和CFA＋Nal＋CVAF组大鼠TWL和MWT均有不同程度的降低（P〈0．01）。结论：初步阐明CVAF通过减少炎性因子的释放对炎性痛大鼠具有镇痛效应。阿片肽受体系统和胆碱能受体系统均部分参与了其对炎性痛大鼠的镇痛作用。

Study on analgesic effect of active component from crude cobra venom in Wannan Area

AIM. To study on analgesic effect of active component from crude cobra venom in Wannan Area（CVAF） and investigate its possi- ble mechanism of analgesic effect. METHODS： Inflammatory pain model of rat （CFA group） was established using CFA （150 L, s. c. ）. 40 male SD rats were randomly divided into 4 groups （n=10）： NC, CFA, CFAq-CVAF and CFAq-Morphine groups. Then another 36 maleSD rats were randomly divided into 6 groups （n =6）. NC, CFA, CFACVAF, CFA＋Atr CVAF, CFA -＋- Nal CVAF and CFA ＋ L- NAME--CVAF groups, the changes of thermal withdrawal latency （TWL） and mechanical withdrawal threshold （MWT）, induced by CVAF, were determined by Spurs pain and me chanical pressure methods, respectively. The levels of interleukin （IL）-I and tumor necrosisfactor （TNF）-a in spinal cord were detected by enzyme-linked immunosorbent assay （ELISA）. Analgesic activity of CVAF was also evaluated in the CFA group after administrating with atro-pine, naloxone or L-NAME. RESULTS. Com- pared with NC group, TWL and MWT were de creased from 1st day to 14th day in CFA group the levels of IL-1 and TNF-a from spinal cord in CFA group were significantly increased （P〈 0.01）. Compared with the CFA group,the TWL and MWT were increased after injecting CVAF, thermal hyperalgesia and mechanical allodynia were also improved simultaneously,the levels of IL-1 and TNF-a were decreased （P〈0.01）, the result showed CVAF played a role in analgesic activity via inhibition of inflammatory factor.Compared with CFA-＋-CVAF group, atropine or naloxone could return the increased TWL and MWT by CVAF （P〈0.01）. The results indicated that both opioid peptide receptor system and cholinergic receptor system could be related to analgesic effect of CVAF for inflammatory pain. CONCLUSION： CVAF plays a role in analgesic effect with inflammatory pain through inhibition of inflammatory factor. Both opioid peptide re ceptor system and cholinergic receptor system are partially involved in the analgesic effect of CVAF for inflammatory pain.