新生大鼠缺氧缺血性脑损伤血管内皮生长因子表达与新生血管形成关系的研究

Correlation between VEGF expression and angiogenesis in brain tissue of neonatal rat with hypoxic-ischemic brain damage

目的观察新生大鼠缺氧缺血性脑损伤（HIBD）后不同时间脑组织中血管内皮生长因子（VEGF）蛋白的表达以及血管新生情况，探讨HIBD时脑组织VEGF蛋白表达与血管新生之间的相互关系。方法7日龄Wistar大鼠176只随机分成实验组（n=88）和对照组（n=88），两组分别在缺氧缺血（HI）后0、4、8、12、24、48、72h及7、14、21、28d（每个时间点8只）应用免疫组织化学染色方法检测VEGF蛋白的表达及血管新生情况。结果正常7日龄Wistar大鼠于脑组织多种细胞的胞浆中可见VEGF表达，9日龄时达高峰；HIBD后VEGF蛋白于HI后4h表达逐渐增加，于48h达高峰后逐渐下降，并且于HI后4h～14dVEGF表达明显高于对照组（P〈0．05，P〈0．01）。正常新生大鼠脑皮质中新生毛细血管数各时间点平均为3～8条／HP；而实验组于HI后3～28d的新生血管数为10～12条／HP，显著多于对照组（P〈0．01），并于HI后4～72hVEGF表达程度与新血管形成之间呈显著正相关（r=0．928，P〈0．05）。结论正常7～35日龄新生大鼠脑组织内有不同程度的VEGF蛋白表达。HI可诱导VEGF表达增加：VEGF参与了HIRD后腩组织新生血管的形成。

Objective To observe the expression of VEGF protein and angiogenesis in the brain of neonatal rats with hypoxic-ischemic brain damage（HIBD） at different time points after hypoxic-ischemia （HI）, and to investigate the correlation between VEGF protein expression and angiogenesis. Methods One hundred and seventy six 7-day-old Wistar rats were randomly divided into HIBD group（ n = 88） and control group（ n = 88）. Eight rats were sacrified at 0, 4, 8, 12, 24, 48, 72 h and 7, 14, 21, 28 d after HI. Hematoxylin and eosin staining and immunohistochemical staining were performed to examine the pathological change as well as the expression of VEGF protein and angiogenesis in brain tissue. Results For normal 7-day-old Wistar rats, VEGF was expressed in the cytoplasm of many brain tissue cells, which reached the peak at the postnatal 9 days. After HI, VEGF protein expression increased at 4 h, with a peak at 48 h, and dcreased over time. From 4h to 14 d after HI VEGF expression levels were significantly higher in HIBD group than that in control group （P〈0.05, P〈0.01）. Micro-vessel in the normal rats cerebral cortical was found 3-8/HP at the every time points. The densities of proliferating brain capillary from 3d to 28 d after HI in HIBD group were significantly higher than those of control（ P 〈 0.01 ）. There was a significandy positive correlation between VEGF expression level and angiogenesis at the 4 - 72 h after HI （ r = 0. 928, P 〈 0.05 ）, Conclusion The expression of VEGF protein is detected in brain of normal newborn rat. HI can up-regulate the expression level of VEGF protein, which involves in the angiogenesis in the brain tissue of neonatal rat HIBD model.