碱性成纤维细胞生长因子对肌成纤维细胞的作用及其对创面愈合的影响

目的　观察碱性成纤维细胞生长因子 (bFGF)对烧伤创面内肌成纤维细胞转归的影响 ,深入探讨bFGF在组织修复中的作用机制。方法　利用大鼠 30 %深Ⅱ°烫伤模型 ,采用原位杂交与免疫组化方法检测伤后不同时间点创面愈合时组织中半胱氨酸天冬氨酸蛋白酶 (caspase- 3)mRNA和蛋白的表达情况 ,并运用免疫组化法观察α -平滑肌肌动蛋白 (ASMA)、转化细胞生长因子 - β1(TGF -β1)的变化情况 ,并对照观察创面应用外源性bFGF后以上各项指标的变化。 结果　创面组织中 β -平滑肌肌动蛋白的表达早期变化不明显 ,伤后第 7天明显升高并达到高峰 ,随后逐渐减弱。创面外用bFGF ,伤后 7～ 14dASMA的表达明显增强。伤后 3h开始 ,TGF - β1的表达逐渐升高 ,至 14d略有所下降。外有bFGF后TGF - β1的表达明显增加 ,并强于单纯烫伤组。伤区局部加用外源性的bFGF ,caspasemRNA和蛋白的表达规律与单纯烫伤组相似 ,呈现先升高后降低 ,再升高样的变化。但第一次峰值低 ,第二次的峰值高于单纯烫伤组。结论　肌成纤维细胞数量的增加与凋亡过程是创面愈合的重要环节。外源性应用bFGF可能够通过提高TGF - β1的分泌 ,进而协同其他生长因子对肌成纤维细胞形成和凋亡发挥作用 ,最终影响愈合的结局。

The effect of basic fibroblast growth factor on myofibroblasts and its significance on wound healing

OBJECTIVE: To observe the effect of basic fibroblast growth factor (bFGF) on the outcome of myofibroblasts in burn wounds, and to further explore the mechanism of bFGF on wound healing. METHODS: Seventy-two Wistar rats were anaesthetized and put into hot water at the temperature of 98 degrees C with their back hair cut so as to cause full-thickness scald injury with an area of 30% of the total body surface. Then the rats were randomly divided into two groups of 36 mice: pure thermal injury group (administered with sterilization and dressing every other day for three times) and bFGF treatment group (administered locally with bFGF every other day in addition to the routine dressing). Three hours, six hours, one day, three days, seven days, and fourteen days after scalding samples of skin wound was taken, six rats for each time-point. Six rats were put into water at the temperature of 37 degrees C as controls and their skin samples were taken 8s after. In situ hybridization and immunohistochemical techniques were employed to detect the expression of caspase mRNA and proteins. alpha-smooth muscle actin (ASMA), and transforming growth factor-beta1 (TGF-beta1) were detected by immunohistochemical staining at different time points after scalding. RESULTS: No obvious difference of ASMA expression in dermal tissues was seen at the early stage of injury. The number of cells with positive ASMA expression began to increase 1 approximately 3 days after and reached the peak by the 7th day after scalding, and then decreased gradually. The ASMA expression in bFGF group was remarkably increased by the 7th day, significantly higher than that in the pure thermal injury group (P < 0.05). By the 14th day, the ASMA expression in the bFGF group was still significantly higher than that in pure thermal injury group (P < 0.01), however, it was much lower than that in the bFGF group by the 7th day. By the 14th days after scald injury. The number of TGF-beta1 positive cells began to increase since the 3rd hour after scald injury and began to decrease by the 14th day in both experimental groups. However, the TGF-beta1 expression in bFGF group was stronger than that in pure thermal injury group. The expressions of caspase-3 mRNA and protein in bFGF group changed in the same way as in the simple injured group. Three hours after injury, the expression of caspase-3 mRNA was lower in bFGF group than in pure injury group (P < 0.05). Then the expression decreased till the 3rd day. Six hours after injury, no difference in the expression of caspase-3 mRNA was found between the two experimental groups. The expression of caspase-3 reached its second peak by the 7th day and then decreased again. However, the first expression peak of the bFGF group was lower than that of the pure thermal injury group, however, the second peak of the bFGF group was higher. CONCLUSION: Myofibroblasts may play a critical role in wound closure and healing. bFGF treatment may increase the expression of TGF-beta1 and have a potential synergistic effect with other growth factors to stimulate the apoptosis of myofibroblasts during wound healing.