褪黑素在脂多糖致幼鼠脑损伤中的保护作用

Protective Effect of Melatonin on Brain Injury Induced by Lipopolysaccharide in Infantile Rats

目的探讨褪黑素(MT)在不同时间点对脂多糖(LPS)致幼鼠脑损伤中的保护作用及意义。方法160只1月龄Spragne-Dawley幼鼠(100～120g)随机分为4组:LPS组、对照组、MT提前15min给药组(A组)和MT0h给药组(B组),每组40只,各组均按观察时间分为24、48h2个时间点,各时间点20只,均有10只不注射伊文思蓝(EB),待观察至相应时间点采用免疫组织化学方法检测各组幼鼠脑组织神经元特异性烯醇化酶(NSE)的表达,原位末端标记法(TUNEL)检测神经细胞的凋亡阳性细胞数,余幼鼠于相应时间点经右颈外静脉近心端注入EB,采用甲酰胺法测定相应时间点脑组织中EB水平。结果各组幼鼠脑组织24、48hNSE阳性区面积、凋亡阳性区面积及EB水平比较,差异均有统计学意义(F=705.44,369.96,1719.05,890.55,1041.46,219.06Pa<0.01)。A、B组幼鼠脑组织24、48hNSE阳性区面积、凋亡阳性区面积及EB水平比较,差异均无统计学意义(t=0.474,0.588,0.842,0.855,0.732,0.90Pa>0.05)。结论LPS可诱导幼鼠脑组织神经细胞凋亡;MT可抑制脑组织凋亡阳性细胞表达,具有显著的抗凋亡作用。

Objective To investigate the protective effect and significance of melatonin （MT） on brain injury induced by lipopolysac- charide （LPS） at different time point in infantile rats. Methods One hundred and sixty Spragne - Dawley rats with 1 month were randomly divided into 4 groups： control group,LPS group, 15 min earlier group （group A） and 0 h group （group B）. Each group with 40 rats was subdivided into 24,48 h 2 time points. Each time point had 20 rats and half of them at each point were not injected Evans blue （EB）. The immunohistochemistry was used to detected neurone specific endase （NSE） expression. Terminal deoxynueleotide mediated nick end labeling （TUNEL） and computer assisted image analysis system methods were applied to observe the expression of the positive apoptosis cell of brain tissue. The EB content of brain tissue was meteraged by the formamide methods. Results The expression of the positive NSE area,positive apoptosis area and the EB content of each group at the 24 h and 48 h time point compared with each other showed there was statistically significant difference（F=705.44, 369.96,1 719.05,890.55,1 041.46,219.06 Pa 〈0.01）.The expression of the positive NSE area,the positive apoptosis area and the EB content between groups A and B at the 24 h and 48 h time point showed there was no signifcant difference （ t = 0. 474,0. 588,0. 842,0. 855,0. 732,0.90 Pa 〉0.05）. Conclusions LPS can induce the neurocyte apoptosis; MT can inhibit the expression of the positive apoptosis cell, MT plays an important role in anti -apoptosis.