AIM: To investigate the effects of insulin-like growth factor 1(IGF-1)on the secretion of transforming growth factor β2(TGF-β2), matrix metalloproteinase 2(MMP-2)and hypoxia-inducible factor 1α(HIF-1α)in human scleral fibroblasts(HSF)and their mechanism.

METHODS: The cells were cultured with IGF-1 and PI3K/AKT pathway inhibitor LY294002, respectively. CCK-8 method was used to detect cell viability and determine the optimal concentration and time of drug action. Cell migration activity was observed by cell scratch method. To determine the effects of IGF-1 on HSF cells and the regulatory role of PI3K/AKT pathway, HSF cells were divided into control group(without drugs), IGF-1(80 μg/L)group, IGF-1+LY294002(80 μg/L+5 mmol/L)group, and LY294002(5 mmol/L)group, and were cultured for 24 h; the protein expression levels of TGF-β2, MMP-2, HIF-1α, PI3K and AKT were detected by Western blot; the fluorescence expression of TGF-β2, MMP-2 and HIF-1α was detected by cellular immunofluorescence.

RESULTS: The results of CCK-8 showed that the cell viability of the 80 μg/L IGF-1 group cultured with different concentrations of IGF-1 was the highest(all P<0.05), and the cell viability of the 80 μg/L IGF-1 group at 24 h was the highest under different culture times. Therefore, the concentration of IGF-1 was selected as 80 μg/L for 24 h. The viability of cells cultured with different concentrations of LY294002 gradually decreased from 6 h(all P<0.05). According to the IC50 value, therefore, the concentration of LY294002 was selected as 5 mmol/L for 24 h. The cell scratch results showed that compared with the control group, the cell mobility of 40 μg/L and 80 μg/L IGF-1 groups was increased(all P<0.05). Compared with the control group, cell mobility in the 2.5 and 5 mmol/L LY294002 groups was decreased(all P<0.05). Western blot results showed that compared with the control group, the protein expressions of TGF-β2, MMP-2, HIF-1α, PI3K and AKT in the IGF-1 group were increased, while those in the LY294002 group were decreased(all P<0.05). Compared with the IGF-1 group, the expression levels of TGF-β2, MMP-2, HIF-1α, PI3K and AKT in the IGF-1+LY294002 group were decreased(all P<0.05). The results of cell immunofluorescence showed that compared with the control group, the fluorescence expressions of TGF-β2, MMP-2 and HIF-1α in the IGF-1 group were increased, while those in the LY294002 group were decreased(all P<0.05). Compared with the IGF-1 group, the fluorescence expressions of TGF-β2, MMP-2 and HIF-1α in the IGF-1+LY294002 group were significantly decreased(all P<0.05).

CONCLUSION: IGF-1 promoted the proliferation and migration of human HSF. IGF-1 may up-regulate the expression of TGF-β2, MMP-2 and HIF-1α in HSF through the PI3K/AKT signaling pathway, and participate in the occurrence and development of myopia.