IFN-γ对大鼠创面愈合中Smad7表达的影响

Effects of interferon-γ on and Smad7 in wound healing of rats' skin

目的:将干扰素γ(IFN-γ)应用于大鼠创面,观察创面肉芽组织的生长、成纤维细胞数目,分析IFN-γ对Smad7的影响。方法:选取成年SD大鼠127只,建立大鼠创伤模型。实验分成A、B、C、D、E共5组,每组25只。A组为生理盐水溶剂对照组,B组为IFN-γ500U/ml溶剂剂量组,C组为IFN-γ1000U/ml溶剂剂量组,D组为2000U/ml溶剂剂量组,E组为空白组,正常对照组2只,为未损伤的正常大鼠。分别于创伤第3、7、10、14、21日随机选取各组5只大鼠采用过量麻醉处死,剪取创面肉芽组织,分别行HE常规染色,在光学显微镜下观察新生肉芽组织厚度、计数成纤维细胞数。行免疫组化染色,在光学显微镜下观察肉芽组织中Smad7的表达情况。结果:各时间点A、B组肉芽组织厚度较C、D组致密且厚(P<0.001),E组肉芽组织厚度介于A、B组和C、D组之间,(P<0.05);200倍光镜下,目测计数成纤维细胞,伤后第3、21天,各组别成纤维细胞数量无差异(P>0.05),伤后第7、10、14天,A、B组成纤维细胞数量比C、D、E组明显增多(P<0.001);通过图像分析检测Smad7平均灰度和平均光密度。Smad7在伤后第3天、第14天表达较强,在C、D组中各时相的表达强于A、B、E组(P<0.001),但C组和D组、A组和B组组间比较无差异(P>0.05)。结论:干扰素γ(IFN-γ)可使新生肉芽组织生长缓慢、成纤维细胞数量减少,延长创面愈合时间,并可使大鼠皮肤创面中Smad7表达增强。

Objective To observe the effect of Smad7 in wound healing of rats＇ skin, and to investigate the growth of granulation tissue and fibroblast count. To analyze the mechanism of IFN-γ on signal transduction of Smad7. Methods Full thickness excisional wound on the back of rats were used as wound models. The rats were divided randomly into 5 groups as follows;①solvent control [saline solution （0.9% NaCl）, group A]; ②IFN-γ 500U/ml [group B]; ③IFN-γ1000U/ml [group C]; ④IFN-γ2000U/ml[group D]; ⑤blank control [group E]. And 2 rats were compared as normal control. Wound tissues were collected on the 3rd,7th,10th,14th and 21st postwounding days. All specimens were dealed with by the pathology tectology （HE） and immunohistochemistry staining technique （SP） to observe the growth of granulation tissue, fibroblast count, the expression level of Smad7. Results The growth of granulation tissue and fibroblast count of groups C and D were less than groups A and B at the same day （P〈0.001）. But on the 3rd and 21st day after wound, there were no differences all the groups on fibroblast count （P〉0.05）. Image analysis showed that there were markable difference of Smad7 among the groups A,B and groups C,D （P〈0.001）, Group E was between them （P〈0.05）. The expression of Smad7 on 3rd and 14th days after wound was higher than other days （P〈0.05）. Conclusion IFN-γcan make growth of granulation tissue slow down and make fibroblast count reduce in wound healing of rats＇skin. After administration, the expression of Smad7 is enhancing