Cheng Biao, Fu Xiaobing, Sheng Zhiyong, Gu Xiaoman, Sun Tongzhu, Sun Xiaoqing
Burn Institute, 304th Hospital of People's Liberation Army, Beijing 100037, China.
Zhonghua Yi Xue Za Zhi. 2002 Sep 10;82(17):1187-91.
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.
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.
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.
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.
观察碱性成纤维细胞生长因子（bFGF）对烧伤创面肌成纤维细胞转归的影响，进一步探讨bFGF促进创面愈合的机制。
将72只Wistar大鼠麻醉后，背部去毛，置于98℃热水中造成30%体表面积的Ⅲ度烫伤。然后将大鼠随机分为两组，每组36只：单纯热损伤组（隔日消毒换药3次）和bFGF治疗组（在常规换药基础上隔日局部应用bFGF）。烫伤后3小时、6小时、1天、3天、7天和14天取皮肤创面标本，每个时间点6只大鼠。另取6只大鼠置于37℃水中作为对照，8秒后取皮肤标本。采用原位杂交和免疫组化技术检测半胱天冬酶（caspase）mRNA和蛋白的表达。烫伤后不同时间点采用免疫组化染色检测α-平滑肌肌动蛋白（ASMA）和转化生长因子-β1（TGF-β1）。
伤后早期真皮组织中ASMA表达无明显差异。ASMA阳性表达细胞数量在烫伤后1～3天开始增加，至第7天达到高峰，随后逐渐下降。bFGF组在第7天时ASMA表达明显增加，显著高于单纯热损伤组（P<0.05）。至第14天，bFGF组ASMA表达仍显著高于单纯热损伤组（P<0.01），但低于bFGF组第7天时的表达。烫伤后14天。TGF-β1阳性细胞数量自烫伤后3小时开始增加，至第14天开始减少，两组均如此。然而，bFGF组TGF-β1表达强于单纯热损伤组。bFGF组caspase-3 mRNA和蛋白表达变化趋势与单纯损伤组相同。伤后3小时，bFGF组caspase-3 mRNA表达低于单纯损伤组（P<0.05）。然后其表达下降至第3天。伤后6小时，两组caspase-3 mRNA表达无差异。caspase-3表达在第7天达到第二个高峰，随后再次下降。然而，bFGF组第一个表达高峰低于单纯热损伤组，但其第二个高峰高于单纯热损伤组。
肌成纤维细胞在创面闭合和愈合中可能起关键作用。bFGF治疗可能增加TGF-β1表达，并与其他生长因子具有潜在协同作用，在创面愈合过程中刺激肌成纤维细胞凋亡。
