MEBT/MEBO对大鼠糖尿病足创面组织TGF-β1、Smad3、P-smad3表达及形态学结构的影响

Effects of MEBT/MEBO on the expression of TGF-β1,Smad3 and P-smad3 and morphological structure in diabetic foot wound of rats

目的:观察皮肤原位再生医疗技术(moist exposed burn therapy/moist exposed burn ointment,MEBT/MEBO)对大鼠糖尿病足创面组织转化生长因子-β1(transforming growth factor-β1,TGF-β1)、Smad3、磷酸化smad3(P-smad3)表达及形态学结构的影响。方法:将80只健康雄性SD大鼠随机分为空白对照组、模型组、贝复济组和MEBT/MEBO组,每组各20只。模型组、MEBT/MEBO组和贝复济组大鼠参照糖尿病模型制备法,采用腹腔注射60 mg/kg链脲佐菌素,建立糖尿病动物模型;空白对照组大鼠则腹腔注射等量柠檬酸-柠檬酸钠缓冲液。分别于干预治疗后第5、14天各取相同部位创面组织,采用Western blot法检测TGF-β1、Smad3和P-smad3蛋白表达水平,常规病理技术观察溃疡创面组织形态学结构,各组间差异比较采用方差分析和秩和检验。结果:治疗后5 d,各组大鼠Smad3蛋白表达水平比较,差异均无统计学意义(F=1.036,P=0.388);MEBT/MEBO组、贝复济组的大鼠TGF-β1和P-smad3蛋白表达水平则均明显低于空白对照组(P=0.005、P=0.026,P=0.001、P=0.005);而且,上述2组大鼠的TGF-β1和P-smad3蛋白表达水平亦明显高于模型组(P=0.000);此外,与第5天结果相比,第14天MEBT/MEBO组与贝复济组的TGF-β1、P-smad3表达水平明显下降,差异均具有统计学意义(P=0.000)。治疗后第5天,MEBT/MEBO组、贝复济组及空白对照组溃疡创面肉芽组织中成纤维细胞形态、毛细血管新生情况优于模型组,但空白对照组成纤维细胞排列紊乱;第14天,MEBO组、贝复济组创面组织成纤维细胞及胶原纤维排列致密成形,空白对照组胶原纤维增生明显但排列紊乱,模型组胶原纤维呈团状增生。结论:MEBT/MEBO在创面愈合早期可激活TGF-β1/Smad3信号通路,促进创面损伤修复,而在愈合晚期则抑制该信号通路的活化,控制创面组织过度增生。

Objective：To investigate the effects of moist exposed burn therapy/moist exposed burn ointment（MEBT/MEBO） on the ex- pressions of transforming growth factor-β1 （TGF-β1）, Smad3 and phosphorylation Smad （P-smad3） and morphological structure in diabetic foot wound of rat. Methods ：Eighty healthy male SD rats were randomly divided into blank control group,treated model group, recombinant bovine basic fibroblast growth factor（rb-bFGF） group and MEBT/MEBO group,each group had 20 rats. Rats in treatedmodel group,rb-bFGF group and MEBT/MEBO group were en- rolled to establish diabetic animal model by intraperitoneal in- jection of streptozotocin each 60 mg/kg;and rats in the blank control group were injected with the same volume of buffer so- lution of citric acid and sodium citrate. The wound tissues were separately collected on 5 d and 14 d after the medication,and the protein expressions of TGF-β1 ,Smad3 and P-smad3 were detected by Western blot and ulcer morphological structure was observed by regular pathological technique. Comparisons among different groups were analyzed by using single factor analysis of variance and rank sum test. Results： After 5 d treatment, there was no significant differences in the protein expression of Smad3 among four groups（F=1.036,P=-0.388）. The protein expression of TGF-β1 and P-smad3 in both MEBT/MEBO and rb-bFGF group were significantly lower than those of control gmup（P=0.005,P=-0.026;P= 0.001 ,P=0.005）. The protein expressions of TGF-151 and P-smad3 of both MEBT/MEBO and rb-bFGF group were also higher than those of treated model group（P=0.000）. In addition,compared with the results of 5 d time point,the protein expressions of TGF-β1 and P-smad3 in MEBT/MEBO and rb-bFGF group were decreased significantly（P=0.000）. After 5 d treatment,fibroblasts and cap- illary growth in MEBT/MEBO group, blank control group and bFGF group were better than that in the model group,while fibroblasts were not well aligned in blank control group. On the 14 d, fibroblasts and collagen fibers in MEBT/MEBO group, bFGF group and blank control group formed a dense arrangement. Collagen fibers in MEBT/MEBO group were proliferated obviously but arrangement was disordered. Collagen fibers in the model group also showed slug hyperplasia. Conclusion：MEBT/MEBO can activate TGF-β1/ Smad3 signaling pathway at the early stage of wound healing, and thus promoting wound healing. However, at the later stage of healing, it can inhibit the excessive activation of this signaling pathway and therefore reducing excessive tissue proliferation.