PI3K/Akt信号通路在增生性瘢痕中的调控作用

Regulatory Role of PI3K/Akt Signaling Pathway in Hypertrophic Scar

目的 探讨PI3K/AKT信号通路在增生性瘢痕中的调控作用。方法 构建兔耳增生性瘢痕模型,并随机分为4组:正常兔耳皮肤组(A)、瘢痕模型组(B)、DMSO刺激模型组(C)、PI3K特异性抑制剂(LY294002)刺激模型组(D)。通过组织病理学观察兔耳瘢痕的形态学变化;免疫组化和Western blot检测pAkt[S473]和p-Akt[T308]的表达量;免疫荧光双染色评估p-Akt[S473]和p-Akt[T308]的共定位情况;以及TUNEL评估皮肤组织中成纤维细胞的凋亡水平。结果 D组中瘢痕厚度及成纤维细胞数明显高于B和C组。免疫组化和Western blot检测结果表明,p-Akt[T308]和p-Akt[S473]在B组中的表达量明显高于A组,但在D组中显著低于C组。免疫荧光表明,p-Akt[T308]和p-Akt[S473]主要定位于瘢痕组织中的细胞浆内,且在D组中的共表达量低于B组。TUNEL检测结果证实,与A组相比,B组皮肤组织中细胞凋亡水平明显下调,且D组中细胞凋亡水平高于C组(P <0.01)。结论 阻断PI3K/Akt信号通路可通过抑制Akt磷酸化,导致成纤维细胞凋亡水平上调,进而缓解瘢痕增生进程。

Objective To explore the regulatory role of PI3K/Akt signaling pathway in the hypertrophic scar. Methods The rabbit ear hypertrophic scar model was established and randomly divided into four groups,including normal rabbit ear skin group(A),hypertrophic scar model group(B),DMSO-stimulated hypertrophic scar model group( C), and PI3K-specific inhibitor( LY294002) stimulated model group( D). Morphological changes of rabbit ear scar were observed by histopathology. The expression of phosphorylation of Akt[S473] and Akt[T308] was examined by immunohistochemistry and western blot. Immunofluorescence double staining was performed to assess the co-localization of p-Akt[S473] and p-Akt[T308]. The TUNEL assay was used to detect the fibroblasts’ apoptosis in skin tissues. Results Scar thickness and fibroblast count were significantly higher in the D group than that in the B and C groups,but the difference was not statistically significant between the B group and the C group. The results of immunohistochemistry and western blot assay confirmed that the expression of p-Akt[T308]and p-Akt[S473] were significantly higher in the B group than in the A group,but significantly lower in the D group than in the C group. The expression of p-Akt[T308] and p-Akt[S473] was significantly enhanced in the B group compared with the C group. Immunofluorescence double staining showed that p-Akt[T308] and p-Akt[S473] were mainly co-localized in the cytoplasm in scar tissue,and their co-expression was lower in the D group than in the B group. TUNEL assay results confirmed that the apoptosis level of fibroblast was significantly downregulated in skin tissue in the B group compared with the A group,and the apoptosis level of fibroblast was higher in the D group than in the C(P < 0.01). Conclusion Blocking the PI3K/Akt signaling pathway can accelerate fibroblast apoptosis by inhibiting Akt phosphorylation,and then alleviate hypertrophic scar formation.