[Knockdown of HMGB1 inhibits proliferation and promotes apoptosis of rat mesangial cells induced by high glucose].

Objective To investigate the effect of knockdown of high mobility group protein B1 (HMGB1) on the proliferation of rat mesangial cells (GMCs) cultured in high glucose (HG) and its mechanism. Methods Rat GMCs was cultured and divided into normal group, high glucose treatment group, negative control small interfering RNA combined with high glucose treatment group (siRNA-NC-HG group) and HMGB1 small interference RNA combined with high glucose treatment group (siRNA-HMGB1-HG group). GMCs in the normal group were cultured in normal DMEM medium. GMCs in the HG treatment group were cultured with HG-DMEM medium. The GMCs in the siRNA-HMGB1-HG group, after transfected with siRNA-HMGB1 sequence for 6 hours, were cultured with high glucose medium for 24 hours. GMCs in the siRNA-NC-HG group, after transfected with siRNA-NC sequence for 6 hours, were cultured in HG medium for 24 hours. HMGB1 mRNA expression levels of GMCs were detected by real-time quantitative PCR. MTT assay was used to detect the proliferation of GMCs. Flow cytometry was performed to assess the apoptosis of GMCs. Western blot analysis was used to detect the protein levels of HMGB1, NF-κBp65 and nuclear factor kappa B inhibitor alpha (IκBα). ELISA was used to detect the levels of interleukin-1β (IL-1β), IL-6 and tumor necrosis factor α (TNF-α) in the cell supernatants. Results Compared with the siRNA-NC-HG group or HG treatment group, HMGB1 mRNA level decreased in GMCs in the siRNA-HMGB1-HG group, and after 24-, 48-, 72- and 96-hour treatment, the proliferation activity and apoptosis rate of GMCs decreased. After knock-down of HMGB1 level of GMCs, the level of NF-κBp65 protein decreased, the level of IκBα protein increased, and the levels of IL-1β, IL-6 and TNF-α in the supernatant decreased. Conclusion Knockdown of HMGB1 inhibits proliferation and promotes apoptosis of GMCs induced by HG, which may be related to the inhibition of NF-κB/IκB-α pathway.