背景:伤口愈合延迟,糖尿病(DM)患者的常见问题,与角质形成细胞自噬受损有关。表没食子儿茶素没食子酸酯(EGCG),儿茶素,已被证明可以促进糖尿病伤口愈合。本研究旨在探讨EGCG对糖尿病创面愈合的治疗机制。
方法:制备高糖(HG)诱导的角质形成细胞和链脲佐菌素(STZ)诱导的DM大鼠,并用EGCG干预,以检查其在体内和体外环境中的治疗效果。AMPK抑制剂,化合物C,用于确定EGCG是否通过AMPK/ULK1途径发挥其治疗作用。
结果:体外,EGCG通过增加LC3II/LC3I改善HG诱导的角质形成细胞自噬损伤,Becline1和ATG5水平和降低的p62水平。机械上,EGCG激活AMPK/ULK1通路,从而通过AMPK和ULK1的磷酸化促进角质形成细胞自噬。值得注意的是,EGCG促进增殖,迁移,在HG处理的角质形成细胞中C-C基序趋化因子配体2(CCL2)的合成和释放。此外,EGCG间接促进成纤维细胞的活化,如α-平滑肌肌动蛋白(α-SMA)和胶原蛋白I水平增加所证明的。在体内,EGCG促进DM大鼠创面愈合,主要通过减少炎症浸润和增加肉芽组织来促进伤口上皮化。此外,EGCG促进ATG5,KRT10,KRT14,TGF-β1,胶原蛋白I,和α-SMA在DM大鼠新生期上皮组织中的表达。然而,化合物C的使用逆转了EGCG的作用。
结论:这些研究结果表明,EGCG通过AMPK/ULK1通路恢复角质形成细胞自噬,促进糖尿病创面愈合。
Delayed wound healing, a common problem in patients with diabetes mellitus (DM), is associated with impaired keratinocyte autophagy. Epigallocatechin gallate (EGCG), a catechin, has been proven to promote diabetic wound healing. This study aims to explore the therapeutic mechanism of EGCG on diabetic wound healing.
High glucose (HG)-induced keratinocytes and streptozotocin (STZ)-induced DM rats were prepared and intervened with EGCG to examine its therapeutic effects in in vivo and in vitro settings. The AMPK inhibitor, Compound C, was utilized to determine whether EGCG exerted its therapeutic effects through the AMPK/ULK1 pathway.
In vitro, EGCG improved HG-induced autophagy impairment in keratinocytes by increasing LC3II/LC3I, Becline1, and ATG5 levels and decreasing p62 level. Mechanically, EGCG activated the AMPK/ULK1 pathway, thereby promoting keratinocyte autophagy through the phosphorylation of AMPK and ULK1. Notably, EGCG promoted the proliferation, migration, synthesis and release of C-C motif chemokine ligand 2 (CCL2) in HG-treated keratinocytes. Furthermore, EGCG indirectly promoted the activation of fibroblasts, as evidenced by increased alpha-smooth muscle actin (α-SMA) and Collagen I levels. In vivo, EGCG promoted wound healing in DM rats, primarily by reducing inflammatory infiltration and increasing granulation tissue to promote wound epithelialization. Besides, EGCG promoted ATG5, KRT10, KRT14, TGF-β1, Collagen I, and α-SMA expressions in the neonatal epithelial tissues of DM rats. However, the use of Compound C reversed the effects of EGCG.
These findings indicated that EGCG restored keratinocyte autophagy to promote diabetic wound healing through the AMPK/ULK1 pathway.