Tea polyphenols delays human glomerular mesangial cells senescence induced by high glucose via regulating STAT3/miR-126/telomere signaling pathway activation / 中国中药杂志

The aim of this paper was to explore the effects and possible mechanisms in vitro of tea polyphenols (TP) delaying human glomerular mesangial cells (HGMCs) senescence induced by high glucose (HG). HGMCs were cultured in vitro and divided into the normal group (N, 5.5 mmol·L⁻¹ glucose), the mannitol group(MNT, 5.5 mmol·L⁻¹ glucose plus 24.5 mmol·L⁻¹ mannitol), the high dose of D-glucose group (HG, 30 mmol·L⁻¹ glucose), the low dose of TP group (L-TP, 30 mmol·L⁻¹ glucose plus 5 mg·L⁻¹ TP) and the high dose of TP group (H-TP, 30 mmol·L⁻¹ glucose plus 20 mg·L⁻¹ TP), which were cultured in 5% CO₂ at 37 °C, respectively. Firstly, the effects of TP on the cell morphology of HGMCs were observed after 72 h-intervention. Secondly, the cell cycle, the positive rate of senescence-associated-β-galactosidase (SA-β-gal) staining and the telomere length were detected, respectively. Finally, the protein expressions of p53, p21 and Rb in the p53-p21-Rb signaling pathway were investigated, respectively. And the expressions of p-STAT3 and miR-126 were examined severally. The results indicated that HG not only arrested the cell cycle in G₁ phase but also increased the positive rate of SA-β-gal staining, and shortened the telomere length. HG led to the protein over-expressions of p53, p21 and Rb and HGMCs senescence by activating the p53-p21-Rb signaling pathway. In addition, L-TP delayed HGMCs senescence by improving the cell cycle G₁ arrest, reducing SA-β-gal staining positive rate and lengthening the telomere length. L-TP reduced the protein over-expressions of p53, P21 and Rb induced by HG and inhibited the telomere-p53-p21-Rb signaling pathway. Moreover, the expression of p-STAT3 was increased and the expression of miR-126 was decreased in HGMCs induced by HG. L-TP reduced the expression of p-STAT3 and increased the expression of miR-126 in HGMCs. In conclusion, HG could induce HGMCs senescence by activating the telomere-p53-p21-Rb signaling pathway in vitro. L-TP could delay HGMCs senescence through regulating STAT3/miR-126 expressions and inhibiting the telomere-p53-p21-Rb signaling pathway activation. These findings could provide the effective interventions in clinic for preventing and treating renal cell senescence in diabetic kidney disease.

Study on the senescence of rat glomerular mesangial cells induced by Tert-Butyl hydroperoxide in vitro and the influnce of probucol on its senescence / 中国综合临床

Objective To investigate the senescence of rat mesangial cells induced by Tert-Butyl hydroperoxide (tBHP) and the protective effect of probucol on senesecence. Methods Human glomerular mesangial cells(hGMC) were cultured in vitro and intervened by tBHP. The cell survival rate was observed by methyl thiazolyl tetrazolium( MTT). β-gal staining and cell cycle analysis were used to identify cell senescent status;transmission eletric microscopy was used to evaluate the ultra-microstructure of hGMC. Senescent-related indexes were detected after treatment with probucol. Results The cell survival rate with 30 μmol/L tBHP was (80. 12 ± 3. 25 ) % , the positive rate of β-gal staining was significantly higher in tBHP-induced cells (about 81% )than that of the control cells( P <0. 01). 86% of the cells was arrested at G0-G1 phase. Invagination of nucleus membrane and chromatin condensation at the nuclear margin in tBHP-induced cells was observed through transmission eletric microscopy. In the probucol intervented cells, the cell survival rate was higher than that of tBHP-induced cells (92. 68 ± 5.03) % vs. ( 80. 12 ± 3. 25) % (P < 0. 05 ). The positive rate of β-gal staining decreased to 45. 2%. The proportion of cell cycle stage was similar to the control cells.The change of morphous and ultrastructure was relieved. Conclusions tBHP can induce hGMC senescence in vitro and probucol may play a role in preventing hGMC senescence.