鞘内泵入吗啡对甲醛炎性疼痛大鼠免疫功能的影响

目的：观察鞘内泵入不同剂量的吗啡对甲醛炎性疼痛大鼠免疫功能的影响。方法：32只SD大鼠随机分为生理盐水对照组(NS组)和3个不同剂量吗啡组（M组），分别为10μg/h（M1），5μg/h（M2），2.5μg/h（M3），每组8只。采用改良Yaksh法进行鞘内置管，Alzet泵持续泵入吗啡、生理盐水。复制甲醛炎性疼痛模型，7d后采用疼痛加权评分（PIS）评价吗啡镇痛效应，分离脾脏单个核细胞进行原代培养，检测脾脏T淋巴细胞增殖水平、NK细胞活性，流式细胞仪检测脾脏T淋巴细胞亚群和NK细胞表型变化。结果：与对照组比较，M1，M2，M3组在甲醛炎性疼痛第一时相和第二时相的PIS差异有统计学意义 (P<0.01),且有量效关系，但3组间比较差异无统计学意义 (P>0.05)；泵入吗啡7d后M1，M2，M3组脾脏指数、T淋巴细胞增殖转化水平和NK细胞活性降低(P<0.05)；CD3+, CD3+CD4+,CD3+CD8+数量及百分率降低，CD4+/ CD8+降低，CD161+数量及百分率降低(P<0.05)。结论：鞘内泵入吗啡对炎性疼痛大鼠具有明显的抗伤害作用；鞘内泵入不同剂量吗啡（10μg/h,5μg/h,2.5μg/h）均可抑制大鼠细胞免疫功能，免疫抑制程度与剂量成正比。

Effect of intrathecal pumping morphine on immunological function in rats with formalin pain

OBJECTIVE: To evaluate the immunological function in rats with formalin inflammatory pain through intrathecal pumping different dosages of morphine. METHODS: Thirty-two Sprague-Dawley rats were randomly divided into 4 groups (n = 8 in each group): saline group (NS) and morphine group included M1 group (10 microg/h) , M2 group (5 microg/h), and M3 group (2.5 microg/h). Chronic intrathecal catheterization was performed under anesthesia with 10% chloral hydrate (300-350) mg/kg according to M2 group (5 microg/h) and M3 group (2. 5 microg/h). Chronic intrathecal catheterization was modified Yaksh's. After 7 days, pain intensity scoring (PIS) was utilized to assess antinociceptive effect of morphine. And spleens were aseptically removed to obtain splenic cells. T lymphocyte function was evaluated based on Concanavalin-A induced splenocyte proliferation. A modified lactic acid dehydrogenase release assay was used to assess NK cell activity. Phenotypic expression of cell surface markers of T lymphocyte subsets (CD3+, CD3+ CD4+, CD3+ CD8+, and CD4+ / CD8+ ) and NK cell ( CD161+) in the spleen were analyzed by flow cytometry. RESULTS: Compared with the NS group, PIS of morphine group decreased obviously (P < 0.01) and was dose-dependent in the early and late phase of formalin pain, but there were no significant differences among morphine groups. Spleen index, splenocyte proliferation and NK cell activity were significantly suppressed by intrathecal pumping morphine. Phenotypic expression of T lymphocyte subsets and NK cell assessed by flow cytometry were different from the control group in all morphine groups. CONCLUSION: There was significant antinociception of intrathecal pumping morphine. After intrathecal pumping different dosages of morphine (10 microg/h,5 microg/h, and 2.5 microg/h), the function of cellular immunity was suppressed and was dose-dependent.