参麦注射液对缺氧缺血性脑损伤新生大鼠IL-18表达的影响

目的:探讨参麦注射液(SMI)对缺氧缺血性脑损伤(HIBD)新生大鼠白介素-18(IL-18)表达的影响,从分子水平了解SMI对缺氧缺血性脑损伤保护作用的机制。方法:建立新生大鼠脑缺氧缺血(HI)模型,①观察缺氧缺血后新生大鼠行为的改变;②采用酶联免疫吸附法(ELISA)检测新生鼠脑缺氧缺血模型后3、12、24h,3、7、14、28天脑组织匀浆中IL-18的水平;③采用HE染色观察脑组织病理改变;④采用免疫组化法检测缺氧缺血性脑损伤模型后3、12、24h,3、7、14、28d新生鼠缺氧缺血侧大脑皮层中IL-18的阳性细胞数。实验动物被随机分为4组(每组32只):假手术组(S)、生理盐水对照组(C)、参麦预处理组(P)、参麦治疗组(SM),参麦治疗组于脑缺氧缺血(HI)后立即腹腔注射SMI10ml·kg-1·d-1,连用7天。生理盐水对照组生理盐水的用法、用量同参麦治疗组。参麦预处理组在缺氧缺血前连续4天腹腔注射SMI10ml·kg-1·d-1。结果:缺氧缺血后3h出现轻度脑损伤,1天病变最严重,3、7天胶质细胞增生,14、28天出现脑萎缩。生理盐水对照组与参麦预处理组、参麦治疗组相比IL-18水平在3h、28天无明显差异(P>0.05),而在12、24h、3、7、14天均明显升高(P<0.01),生理盐水对照组与假手术组相比除在3h、28天无明显差异(P>0.05)外,在12、24h,3、7、14天有显著差异(P<0.01);预处理组与参麦治疗组比较在各时间段均无明显差异(P>0.05)。IL-18在各组均为12h开始上升,3天达高峰,7天开始下降,28天则基本恢复正常;利用免疫组化法检测左侧大脑半球脑缺氧缺血后表达IL-18的阳性细胞数,生理盐水对照组、参麦预处理组、参麦治疗组与假手术组相比,IL-18阳性细胞数在12、24h,3、7、14、28天均有明显升高(P<0.01),而3h无明显差异(P>0.05);生理盐水对照组与参麦预处理组、参麦治疗组相比在12、24h,3、7、14、28天均有显著性差异(P<0.01);参麦预处理组与参麦治疗组在3、12、24h,3、7、14、28天比较均无明显差异(P>0.05)。结论:参麦注射液可显著降低IL-18水平,对新生大鼠HIBD的保护作用可能与低IL-18的表达有关。

The influence of Shenmai injection on IL - 18 expression in neonatal rats with hypoxic- ischemic brain damage

Objective:To investigate the effect of Shenmai injection (SMI) on the expression of IL-18 in neonatal rats with hypoxic-ischemic brain damage(HIBD),and clarify the protection of SMI for HI brain damage from molecule level.Methods: HI models were established, ①The behaviour of neonatal rat was observed after HI insult; ②Level of IL-18 in brain homogenates of HIBD was examined by ELISA at 3, 12, 24 h, 3, 7, 14, 28 d; ③The pathological change of brain tissue was observed by HE staining; ④The counts of positive cell that expressing IL-18 in HI cerebral cortex were detected by immunohistochemistry at 3, 12, 24 h, 3, 7, 14, 28 d. Experimental animals were randomly divided into four groups (n= 32): sham group (S), control group C, normal saline was also injected intraperitoneal(i.p.)immediately after HI insult once a daily for 7 days],Shenmai pretreatment group (P, since 4 days before the experiment, Shenmai injection 10 ml/kg was injected intraperitoneal once a day for 4 days), Shenmai treatment group SM, Shenmai injection was injected intraperitoneal(i.p.)immediately after HI insult once a daily for 7 days].Results:In HI group, slight brain injury occurred at 3 h, severe brain injury appeared at 1 d, glial cells proliferated at 3 and 7 d, brain atrophy was found at 14 and 28 d. Level of IL-18 in control group(C)at 12, 24 h, 3, 7, 14 d after HI insult was significantly higher than that in group P and group SM (P<0.01), and also was group S(P<0.01), but was not significantly higher than that of group P, group SM and group S at 3 h, 28 d.(P>0.05), and there was no obvious difference in level of IL-18 between group P and group SM(P>0.05). The level of IL-18 in HI insult was gradually increased at 12 h after HI,and reached the peak at 3 d,then gradually decreased at 7 d,recovered normal at 28 d; The counts of positive cells that expressing IL-18 in HI cerebral cortex were detected by immunohistochemistry, compared to group S, the counts in group C, group P and group SM were significantly higher at 12, 24 h, 3, 7, 14, 28 d after HI (P<0.01), but was not significantly higher at 3 h(P>0.05);The counts in group C was significantly higher than that in group P and group SM at 12, 24 h, 3, 7, 14, 28 d after HI (P<0.01), and also was group S (P<0.01); There was no obvious difference in the expression of IL-18 between group P and group SM at 3, 12, 24 h, 3, 7, 14, 28 d after HI (P>0.05).Conclusion:The level of IL-18 could be decreased distinctly by Shenmai injection, which may result in a protective effect for neonatal rats with HI brain damage.