基质金属蛋白酶-9在大鼠重度脑创伤中的表达及意义

【目的】研究大鼠重度脑创伤后脑组织基质金属蛋白酶-9（matrix metalloproteinase，MMP-9）mRNA的表达，探讨其在脑创伤中的作用。【方法160只健康成年SD大鼠随机分为假手术组和脑创伤组，每组又按处死时间点即伤后4h、1d、3d、5d和7d分为五个亚组，每亚组6只。取伤区脑组织用干湿重法测含水量、反转录聚合酶链式反应（RT—PCR）法测MMP-9mRNA和电镜检查。【结果】大鼠重度脑创伤后脑组织含水量和MMP-9mRNA在伤后4h开始升高，1d达高峰，持续至3d，然后下降，7d达最低；除7d外脑组织含水量和MMP-9mRNA均明显高于假手术组，差异有统计学意义（P〈0．05）。【结论】大鼠重度脑创伤诱导MMP-9mRNA表达，MMP-9可能参与了脑水肿的形成，在脑创伤后继发性脑损伤中起重要作用。

Expression of Matrix metalloproteinase-9 in Rats after Severe Traumatic Brain Injury and Its significance

[Objective] To study the expression of matrix metalloproteinase-9 （ MMP-9）mRNA in brain tissue of rats after severe traumatic brain injury（TBI） and to discuss the effect of MMP-9 in severe TBI. [Methods] Sixty healthy adult Sprague-Dawley rats were randomly divided into two groups： sham operation group （SO group） and severe TBI group. The subjects were sacrificed at 4h, and 1, 3, 5, 7 days. Groups were divided into five subgroups according to the five time points （ n = 6 in each subgroup）. The samples of injured brain tissue were collected to detect the content of water by dry-net method, the expression of MMP-9 mRNA was detected by RT-PCR, and the ultrastructural studies were examined by electric microscope. [Re- sults] The content of water and expression of MMP-9 mRNA in brain tissue increased at 4h, the peak value appeared at 1～3d after severe TBI, declined at 5d, with a minimum observed at 7d. In TBI group, the content of water and expression of MMP-9 mRNA in injured brain tissue were significantly higher than those in SO group at 4h, ld, 3d and 5d after severe TBI （ P d0.05）. [Conclusions] The expression of MMP-9 mRNA can be induced to increase after severe TBI in rats. It is strongly suggested that MMP-9 may participate in the traumatic brain edema and play an important rol in secondary brain injury after TBI.