China ; epidemiology ; Humans ; Incidence ; Mining ; economics ; Occupational Exposure ; Silicosis ; epidemiology

Objective:To observe the effect of high glucose downregulated microRNA(miR)-99a on hepatic sinus dysfunction and metformin intervention, and to explore the pathogenesis of diabetes-induced fatty liver and possible mechanism of metformin.Methods:The cultured human liver sinusoidal endothelial cells were randomly divided into normal control group, high glucose model group, miR-99a overexpression group, miR-99a overexpression negative control group, insulin-like growth factor 1 receptor(IGF-1R) inhibitor group, mammalian target of rapamycin(mTOR) inhibitor group, and metformin treatment group. The mRNA expressions of miR-99a were detected with realtime quantitative PCR(RT-qPCR), and the expression levels and distribution of IGF-1R, phosphorylated(p-)mTOR and vitronectin(VN) were detected by Western blotting and immunofluorescence. The ultrastructure of human liver sinusoidal endothelial cells was observed using scanning electron microscope.Results:Compared with normal control group, the mRNA expression of miR-99a was downregulated( P=0.008), while the protein expressions of IGF-1R, mTOR, and VN were significantly increased, and the diameter and number of fenestrae decreased significantly in high glucose model group. Compared with high glucose model group, after the treatment with metformin, the mRNA expression of miR-99a was upregulated, while the protein expressions of IGF-1R, mTOR, and VN were significantly decreased( P=0.001, P=0.016, P=0.005, respectively), the number of fenestras increased and the diameter became larger in miR-99a overexpression group, IGF-1R inhibitor group, mTOR inhibitor group, and metformin treatment group. After overexpression of miR-99a, the protein expressions of IGF-1R, p-mTOR, and VN were significantly reduced( P=0.007, P=0.013, P=0.003, respectively); After administration of IGF-1R inhibitors, the expressions of p-mTOR and VN significantly decreased( P=0.006, P=0.009, respectively), following treatment with the mTOR inhibitor, the expression of VN was significantly reduced( P=0.008), while the expression of IGF-1R remained unchanged( P=0.553). Conclusions:Downregulating of miR-99a with high glucose induced hepatic sinus dysfunction, which may be related to the regulation of IGF-1R/mTOR pathway. Metformin increased the expression of miR-99a, thereby inhibiting high glucose-induced hepatic sinusoidal dysfunction.