碱性成纤维细胞生长因子对缺氧缺血性脑损伤新生鼠骨形态发生蛋白4及其mRNA表达的影响

Effect of basic fibroblast growth factor on expression of protein and mRNA of bone morphogenetic protein 4 in hypoxic-ischemic brain damage in newborn rats

目的探讨碱性成纤维细胞生长因子（basicfibroblastgrowthfactor，bFGF）对新生鼠HIBD骨形态发生蛋白4蛋白及其mRNA表达的影响。方法新生7日SD乳鼠120只，随机分①bFGF组、②HIBD组、③正常对照组，每组40只。HIBD模型建立后①组予以bFGF干预，腹腔注射，连用5d，根据处死时相点各组又分为7、14、21、28d等4个小组。采用免疫组化技术检测各组骨形态发生蛋白4（BMPd）蛋白在海马的表达；采用原位杂交技术检测各组BMP4mRNA在海马的表达；采用TUNEL实验检测各组神经细胞的凋亡。采用随机组设计资料的方差分析进行组间及组内比较。结果在7d和14d时相点，bFGF组BMP4蛋白在海马的表达较HIBD组多；2组在14d时相点BMP4蛋白在海马的表达较7d时相点弱。21d小组、28d小组等BMP4蛋白在海马的表达3组之间数量无明显变化。在7d时相点，HIBD组、bFGF组CA1区BMP4mRNA表达明显，较正常对照组明显增加；在14d时相点，HIBD组BMP4mRNA在病侧海马广泛表达，bFGF组仅病侧海马CAI区BMP4mRNA表达明显，但2组较正常对照组明显增加；21d时相点BMP4mRNA在HIBD组、bFGF组海马的表达均显著；28d时相点BMPdmRNA在HIBD组病侧海马的表达开始减少，而bFGF组BMP4mRNA在病侧海马的表达无变化。bFGF组凋亡神经细胞在7d时相点较HIBD组少[（20．10±0．35）vs（29．12±0．31）；F=9．010，P〈0．01]；在14、21、28d3个时相点，HIBD组和bFGF组凋亡神经细胞均较7d时相点增多，bFGF组凋亡神经细胞仍较HIBD组少[（28．09±0．26）vs（37．46±0．23）；（18．75±0．71）vs（35．36±0．77）；（12．26±0．57）vs（25．70±0．21）；F=9．202，7．932，14．985，P〈0．01]。结论bFGF对HIBD具有神经修复作用，其作用机制是促进BMP4蛋白及其mRNA在新生鼠HIBD海马的表达，并抑制神经细胞的凋亡。

Objective To investigate the effect of basic fibroblast growth factor （bFGF） on expression of protein and mRNA of bone morphogenetic protein 4 in bypoxic-ischemic brain damage （HIBD） in newborn rats. Method One hundred and twenty 7 days old neonatal rats were randomly divided into control group, hypoxic-ischemic brain damage and interventional group of bFGF, each having forty neonatal rats. After HIBD model was established, bFGF was given to interventional group by peritoneal injection for 5 continuous days. Every group was randomly divided into 7 days, 14 days, 21 days and 28 days group, according to the time of sacrifice. BMP4 protein in hippocampus was determined with immunohistochemical method. Messenger RNA of BMP4 were determined with in situ hybridization. Apoptosis of nerve cell was determined with TUNEL Intergroup or intragroup comparisons were performed with analysis of variance. Result On the days 7 and 14, expression of BMP4 protein in hippocampus was higher in interventional group of bFGF than in HIBD while expression of BMP4 protein in interventional group of bFGF and HIBD was lower on day 7 than on day 14. Expression of BMP4 protein on the days 21 and 28 had no significant difference among three groups, mRNA expression of BMP4 in interventional group of bFGF and HIBD was significantly higher in hippocampus than in control group. On the day 14, BMP4 mRNA in hippocampus widely expressed in HIBD while BMP4 mRNA only expressed in CA1 in interventional group of bFGF. Expression of BMP4 mRNA in hippocampus on the affected side decreased from the time of killing on 28th day while there was no significant change in interventional group of bFGF. Apoptosis of neural cells at the time of sacrifice on day 7 was lower in interventional group of bFGF than that in HIBD group（ F = 9. 010, P 〈0. 01 ）. Apoptotic neural cells was higher in bFGF and HIBD groups at the time of killing on days 14, 21 and 28 than that on day 7 but that the bFGF group had less apoptotic neural ceils than HIBD group（ F= 9. 202,7. 932, 14. 985, P 〈 0. 01 ）. Conclusions bFGF has a neurorestoration effect, which promotes expression of BMP4 protein and BMP4 mRNA in hippocampus of HIBD and inhibit apoptosis of neural cells.