Fu X, Yang Y, Li X, Sun T, Wang Y, Sheng Z
Trauma Center of Postgraduate Medical College, 304th Hospital, 51 Fu Cheng Road, Beijing, 100037, People's Republic of China.
J Surg Res. 1998 Nov;80(1):88-93. doi: 10.1006/jsre.1998.5349.
Our previous studies showed that the amount of endogenous basic fibroblast growth factor (bFGF) was reduced after ischemia and reperfusion insult. One of the mechanisms involved in the decrease of endogenous bFGF is the increased destruction of this growth factor associated with oxygen free radical activation and inflammation. We hypothesized that the wounding also impairs the secretion of bFGF and examined the bFGF gene expression in skeletal muscles after ischemia and reperfusion insult. In this study, a rat leg ischemia (4 h) and reperfusion (24 h) injury model was prepared and the in situ hybridization method and reverse transcriptase polymerase chain reaction technique (RT-PCR) were used to evaluate the bFGF gene expression and its localization in control (normal) and injured rat skeletal muscles. The results showed that the bFGF mRNA expression was localized in the cytoplasm in control skeletal muscle, especially at the periphery inside the cells. According to the intensity of the stain, four main classes of fibers could be identified: strongly, moderately, weakly, and negatively stained fibers. Based on the positive stain, about 82% of the total fibers examined were positive for bFGF mRNA stain. In ischemic or ischemic and reperfused rat skeletal muscles, the localization of bFGF mRNA expression was similar to that in normal skeletal muscles, but only 52% in ischemic muscles and 22% in ischemic and reperfused muscles had positive bFGF mRNA staining. RT-PCR confirmed a significant decrease in bFGF mRNA expression in ischemic and reperfused rat skeletal muscles. These results suggest that the acute ischemia and reperfusion not only induce the destruction of endogenous bFGF molecule, which is stored at the extracellular matrix of the fibers, but also downregulate the bFGF gene expression. The simultaneous dysregulation of endogenous bFGF gene expression and decreased synthesis of bFGF protein suggest a possible role of this growth factor in delayed wound healing.
我们之前的研究表明，缺血再灌注损伤后内源性碱性成纤维细胞生长因子（bFGF）的量会减少。内源性bFGF减少所涉及的机制之一是与氧自由基激活和炎症相关的该生长因子破坏增加。我们推测创伤也会损害bFGF的分泌，并研究了缺血再灌注损伤后骨骼肌中bFGF基因的表达。在本研究中，制备了大鼠腿部缺血（4小时）和再灌注（24小时）损伤模型，并使用原位杂交方法和逆转录聚合酶链反应技术（RT-PCR）来评估bFGF基因在对照（正常）和损伤大鼠骨骼肌中的表达及其定位。结果显示，bFGF mRNA表达定位于对照骨骼肌的细胞质中，特别是在细胞内部的周边区域。根据染色强度，可以识别出四类主要纤维：强染色、中度染色、弱染色和阴性染色纤维。基于阳性染色，所检查的总纤维中约82%的bFGF mRNA染色呈阳性。在缺血或缺血再灌注的大鼠骨骼肌中，bFGF mRNA表达的定位与正常骨骼肌相似，但缺血肌肉中只有52%以及缺血再灌注肌肉中只有22%的bFGF mRNA染色呈阳性。RT-PCR证实缺血再灌注大鼠骨骼肌中bFGF mRNA表达显著降低。这些结果表明，急性缺血再灌注不仅诱导储存在纤维细胞外基质中的内源性bFGF分子的破坏，还下调bFGF基因表达。内源性bFGF基因表达的同时失调和bFGF蛋白合成的减少表明该生长因子在伤口愈合延迟中可能起作用。
