胰岛素对结肠平滑肌细胞增殖及其表达干细胞因子的影响

High glucose down-regulates the expression of endogenous insulin-like growth factor-1 in rat colonic smooth muscle cells

AIM: To investigate the effect of high glucose on the expression of endogenous insulin-like growth factor-1 (IGF-1) in rat colonic smooth muscle cells (SMCs).

METHODS: Rat colonic SMCs were separated, cultured, identified by immunofluorescence staining of α-actin, and divided into three groups: normal glucose group (5.5 mmol/L glucose), mannitol control group (5.5 mmol/L glucose plus 19.5 mmol/L mannitol) and high glucose group (25 mmol/L glucose). After treatment, cell proliferation was determined using Cell Counting Kit-8, and cell cycle analysis was performed by flow cytometry. ELISA was designed to measure the content of IGF-I in SMCs culture supernatants. Real-time quantitative-PCR and Western blotting were performed to analyze the mRNA and protein expression of IGF-1 in SMCs.

RESULTS: Compared to the normal glucose group, treatment with high glucose significantly inhibited the proliferation of rat colonic SMCs (0.494 ± 0.0030 vs 0.597 ± 0.044, P < 0.05), resulted in cell accumulation in the G₁ phase (90.850% ± 0.706% vs 55.202% ± 3.807%, P < 0.05) and a significant decrease in the percentage of cells in the S phase (3.622% ± 0.156% vs 30.780% ± 3.808%, P < 0.05), and decreased the content of IGF-I in SMCs culture supernatants (208.000 ng/L ± 31.443 ng/L vs 265.750 ng/L ± 26.538 ng/L, P < 0.05) and the expression of IGF-I mRNA and protein (2.037 ± 0.196 vs 2.257 ± 0.273; 0.247 ± 0.045 vs 0.906 ± 0.103, both P < 0.05). However, there were no significant differences in the above parameters between the normal glucose group and mannitol control group.

CONCLUSION: High glucose inhibits the proliferation of rat colonic SMCs and decreases the expression of endogenous IGF-1 in SMCs.