急性一氧化碳中毒大鼠脑组织损伤中巨噬细胞介导的非特异性免疫反应研究

摘要

Objective To investigate the effect of nonspecific immune reaction mediated by macrophages on brain injury induced by acute carbon monoxide (CO) poisoning in rats.Methods Twenty-four male healthy rats were randomly divided into the 3 days after CO poisoning group (or group A),the 7 days after CO poisoning group (or group B) and the normal control group (or group C),each consisting of 8 animals.Models of acute CO poisoning were established by using the animals in group A and group B.Samples of the brain tissue were collected following abdominal anesthesia.Electron microscopy,immunohistochemistry and Western blot were used to observe changes in ultra-structure of the brain tissue,infiltration of macrophages and the expression of related cytokines.Results Following acute CO poisoning,neuronal degeneration,necrosis and microglia accumulation around the injured neurons could be observed under electron microscopy.Macrophage infiltration and expressions of macrophage inflammatory protein-1α (MIP-1 α) and intercellular adhesion molecule-1 (ICAM-1) were observed in the brain of rats,while for the animals in the control group,there was little expression of macrophage specific protein (ED-1).The No.of positive cells in the cortex was 2.83 ± 1.72,and the No.of positive cells in the hippocampus was 2.33 ± 1.37.The peak of macrophage infiltration was seen 7 days after CO poisoning,with the No.of positive cells in the cortex being 30.33 ± 1.14 and the No.of positive cells in the hippocampus being 16.00 ± 1.41.Statistical significance could be seen,as compared with those of the control group (P ＜ 0.05).However,there was little the expression of MIP-1 α in the control group.Under the electron microscope,the No.of positive cells in the cortex was 5.83 ± 2.48 and the No.of positive cells in the hippocampus was 6.67 ±2.94.The expression of MIP-1α for group A was most significant,with the No.of positive cells in the cortex being 238.33 ± 11.94 and the No.of positive cells in the hippocampus being 207.83 ± 9.79.Statistical significance could be noted,when comparisons were made with the control group(P ＜0.01).The trend in expression of ICAM-1 was identical to that of MIP-1α,but little expression of ICAM-1 could be seen in the control group,with IOD in total brain being 10.56 ± 16.11.The expression for group A was most significant,with IOD in total brain being 845.77 ± 80.70.And statistical significance could be noted,when comparisons were made with the control group(P ＜0.01).Conclusions Nonspecific immune reaction mediated by macrophages was involved in brain injury,following acute CO poisoning,and the reaction might be associated with the chemotactic effect of cytokines.%目的 探讨急性一氧化碳(CO)中毒大鼠脑组织损伤中巨噬细胞介导的非特异性免疫反应.方法 清洁级雄性SD大鼠24只,按数字表法随机分为正常对照组(对照组)、CO中毒3d组(中毒3d组)和CO中毒7d组(中毒7d组),每组8只.中毒3d组和中毒7d组建立急性CO中毒大鼠模型,中毒3d组于建模后3d、对照组和中毒7d组于建模后7d腹腔麻醉后灌注、取脑,应用电镜、免疫组织化学染色和免疫印记等方法观察各组脑组织超微结构的改变、巨噬细胞的浸润以及相关细胞因子的表达.结果 电镜下,急性CO中毒后的大鼠脑组织,神经元发生变性坏死、小胶质细胞聚集在损伤神经元周围;脑内有巨噬细胞浸润、巨噬细胞炎性蛋白-1α(MIP-1 α)和细胞间黏附分子-1(ICAM-1)的表达.对照组巨噬细胞特异性蛋白(ED-1)表达较少,5个高倍视野内阳性细胞数,皮层(2.83±1.72)个,海马(2.33±1.37)个;中毒7d组表达最显著,皮层(30.33 ±1.14)个,海马(16.00±1.41)个,与对照组比较差异均有统计学意义(P＜0.01).对照组MIP-1α表达较少,5个高倍视野内阳性细胞数,皮层(5.83±2.48)个,海马(6.67±2.94)个;中毒3d组表达最显著,皮层(238.33±11.94)个,海马(207.83±9.79)个,与对照组比较差异均有统计学意义(P＜0.01).ICAM-1表达趋势与MIP-1α一致,对照组表达较少,全脑5个高倍视野内积分光密度值(IOD)为10.56±16.11;中毒3d组表达最显著,IOD为845.77±80.70,与对照组比较差异有统计学意义(P＜0.01).结论 急性CO中毒大鼠脑损伤后,有巨噬细胞介导的非特异性免疫炎症反应参与,且这一反应可能与细胞因子的趋化作用有关.