Study on the mechanism of mTOR/HIF-1α signaling pathway in Budd-Chiari syndrome liver fibrosis / 国际外科学杂志

ABSTRACT

Objective:To explore the mechanism of mTOR/HIF-1α signaling pathway in Budd-Chiari syndrome (B-CS) liver fibrosis.Methods:Twenty male C57 mice were randomly divided into Sham operation group (Sham), sham operation+ rapamycin (Sham+ Ra) group, B-CS group, B-CS+ rapamycin (B-CS+ Ra) Group, 5 in each group. The B-CS mouse model was constructed by partial ligation of the inferior vena cava(IVC) at the posterior segment of the liver; IVC was not ligated in the Sham group. Mice in Sham+ Ra and B-CS+ Ra groups were intraperitoneally injected with rapamycin (2 mg/kg, 5% DMSO solution preparation) every other day, Sham group and B-CS group were injected with the same dose of 5% DMSO solution.After 6 weeks, samples were taken, and part of the liver tissue was used to make paraffin sections for hematoxylin-eosin (HE) and Sirus Red staining to observe the pathological changes, and immunohistochemical staining to detect the expression of α-SMA and Fibrinogen in liver tissues; Protein and RNA were extracted from fresh liver tissue, and Western-blot was used to detect α-SMA, Fibrinogen, p-mTOR, mTOR, HIF-1α, Collagen I, and VEGF protein levels. Real-time fluorescent quantitative PCR was used to detect mTOR, HIF-1α, CollagenⅠ, VEGF mRNA levels.Measurement data were expressed as mean±standard deviation ( ± s), and the comparison between groups was performed by one-way ANOVA test. Results:The results of pathological staining showed that in the B-CS group, there was severe congestion around the central vein of the liver and sinusoids, widening of the sinus space, and increased collagen deposition, indicating that this study successfully established a mouse B-CS liver fibrosis model. The expression levels of fibrosis indicators α-SMA and Collagen I protein, mTOR pathway related indicators p-mTOR and HIF-1α protein, and microthrombus indicator Fibrinogen protein in the Sham group were 0.027±0.012, 0.337±0.008, 0.138±0.024, 0.296±0.113, 0.733±0.192; B-CS group were 0.986±0.001, 0.927±0.055, 0.936±0.044, 1.693±0.443, 1.612±0.068, and the differences were statistically significant ( P<0.05). The expression levels of B-CS+ Ra group were 0.707±0.078, 0.311±0.024, 0.332±0.094, 0.254±0.117, 0.569±0.075, which were statistically significant compared with B-CS group ( P<0.05). Conclusions:The mTOR/HIF-1α signaling pathway is significantly activated in mouse B-CS liver fibrosis. This pathway may participate in the development of liver fibrosis by regulating microthrombosis.