芦荟凝胶多糖对急性放射性皮肤损伤模型的修复作用及机制研究

目的研究芦荟凝胶多糖基于磷脂酰肌醇3-激酶(PI3K)-蛋白激酶B(Akt)-雷帕霉素靶蛋白(mTOR)信号通路对急性放射性皮肤损伤模型的修复作用。方法选取40只雄性Wistar大鼠,10只为正常组(等体积生理盐水),其余30只建立急性放射性皮肤损伤模型,随机分为模型组、低剂量组、高剂量组,每组10只。模型组和正常组均给予等体积生理盐水干预,低剂量组、高剂量组分别以单层纱布浸润0.4 mg/mL、0.8 mg/mL的芦荟凝胶多糖外敷干预。记录创面愈合时间、放射性皮肤损伤评级,检测创面微血管密度、血管内皮生长因子(VEGF)含量,病理学观察创面组织细胞形态,Western blot检测PI3K-Akt-mTOR信号通路相关蛋白表达。结果低剂量组和高剂量组创面愈合时间均短于模型组,且高剂量组创面愈合时间显著短于低剂量组(P<0.05);与模型组相比,正常组大鼠0级较多,Ⅳ级较少;低剂量组和高剂量组大鼠Ⅳ级较少(P<0.05)。模型组、低剂量组、高剂量组创面微血管密度、VEGF、PI3K、Akt蛋白表达量低于正常组,mTOR蛋白表达量高于正常组;低剂量组、高剂量组创面微血管密度、VEGF、PI3K、Akt蛋白表达量高于模型组,mTOR蛋白表达量低于模型组;高剂量组创面微血管密度、VEGF、PI3K、Akt蛋白表达量高于低剂量组,mTOR蛋白表达量低于低剂量组。结论高剂量芦荟凝胶多糖可通过调控PI3K-Akt-mTOR信号通路促进急性放射性皮肤损伤模型创面新生血管形成,加快创面修复。

Repair effect and mechanism of polysaccharide isolated from aloe vera gel on acute radiation-introduced skin damage model

Objective To study the repair effect of polysaccharide isolated from aloe vera gel on acute radiation-introduced skin damage models through phosphatidylinositol 3-kinase(PI3K)-protein kinase B(Akt)-mammalian target of rapamycin(mTOR)signaling pathway.Methods A total of 40 male Wistar rats were selected,10 rats of them were included into the normal group(equal volume of normal saline),and the remaining 30 rats were randommizedly divided into the model group,the low dose group,and the high dose group,with 10 rats in each group for the establishment of acute radiation-introduced skin damage models.Rats in the normal group and the model group were given equal volume of normal saline for intervention,and those in the low dose group and the high dose group were given single layer of gauze infiltrated with 0.4 mg/mL and 0.8 mg/mL polysaccharide isolated from aloe vera gel for intervention.The wound healing time,radiation-induced skin damage rating were recorded,wound microvessel density,vascular endothelial growth factor(VEGF)content were detected,wound cell morphology was observed by HE staining,expression levels of PI3K-Akt-mTOR signaling pathway related proteins were detected by Western blot.Results The wound healing time of the low dose group and the high dose group was shorter than that of the model group,and the wound healing time of the high dose group was significantly shorter than that of the low dose group(P<0.05).Compared with the model group,there were more rats of grade 0 and less rats of gradeⅣin the normal group;and there were less rats of gradeⅣin the low dose group and the high dose group(P<0.05).The wound microvessel density expression levels of VEGF,PI3K and Akt proteins in the model group,the low dose group and the high dose group were lower than those in the normal group,and the expression level of mTOR protein was higher than that of the normal group.The wound microvessel density,expression levels of VEGF,PI3K and Akt proteins in the low dose group and the high dose group were higher than those in the model group,and the expression level of mTOR protein was lower than that of the model group.The wound microvessel density,expression levels of VEGF,PI3K and Akt proteins in the high dose group were higher than those in the low dose group,and the expression level of mTOR protein was lower than that of the low dose group.Conclusion High dose of polysaccharide isolated from aloe vera gel can promote angiogenesis and accelerate wound healing in acute radiation-introduced skin damage models through regulating PI3K-Akt-mTOR signaling pathway.