Effects of chikusetsu saponin Ⅳa on high glucose-induced human renal tubular epithelial cell injury through regulating circEIF4G2/miR-379-5p

Objective To explore the effect of chikusetsu saponin Ⅳa (CHS) on high glucoseinduced human renal tubular epithelial cells (HK-2) injury and examine whether or not its mechanism is correlated with the regulation of circEIF4G2 and miR-379-5p expression. Methods HK-2 cells were divided into 10 groups of normal glucose (NG) (5.0 mmol/L glucose),high glucose (HG),HG+CHS 25 μM,HG+CHS 50 μM,HG+CHS 100 μM,HG+si-NC,HG+si-circEIF4G2,HG+CHS+ pcDNA and HG+CHS+pcDNA-circEIF4G2. Flow cytometry was performed for detecting apoptotic rate and kit employed for evaluating intracellular malondialdehyde (MDA) level and superoxide dismutase (SOD) activity. The levels of circEIF4G2 and miR-379-5p were assessed by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). And targeting relationship between circEIF4G2 and miR-379-5p was verified by dual lucifase reporting assay. Results Compared with NG group,apoptotic rate (7.62±0.74)% vs (23.81±1.45)%,MDA level (139.17±13.60) nmol/mL vs (637.50±59.93) nmol/mL and relative level of circEIF4G2 (0.96±0.07) vs (3.00±0.15) spiked markedly in HG group (P<0.05) while SOD activity (165.05±16.52) U/L vs (55.77±7.30) U/L and relative level of miR-379-5p (1.00±0.00) vs (0.14±0.02) dropped obviously (P<0.05). Compared with HG group,apoptotic rate (23.81±1.45)% vs (20.70±1.07)% vs (16.78±0.87)% vs (11.06±0.77)%,MDA level (637.50±59.93) nmol/mL vs (533.36±17.83) nmol/mL vs (407.51±34.34) vs (276.04±15.15) nmol/mL and relative level of circEIF4G2 (3.00±0.15) vs (2.26±0.10) vs (1.75±0.07) vs (1.33±0.11) declined markedly in HG+CHS 25/50/100 μM group (P<0.05) while SOD activity (55.77±7.30) U/L vs (79.99±8.95) U/L vs (118.67±11.73) U/L vs (144.78±8.52) U/L and relative level of miR-379-5p (0.14±0.02) vs (0.29±0.03) vs (0.48±0.06) vs (0.75±0.07) spiked obviously (P<0.05). And circEIF4G2 was directly conjugated with miR-379-5p. Compared with HG+si-NC group,apoptotic rate (23.93±1.32)% vs (13.77±1.18)% and MDA level (642.24±52.33) nmol/mL vs (311.91±20.40) nmol/mL declined markedly in HG+si-circEIF4G2 group (P<0.05) and SOD activity (55.41±7.75) U/L vs (130.67±13.17) U/L and relative level of miR-379-5p rose significantly (1.00±0.00) vs (4.13±0.11) (P<0.05). Compared with HG+CHS+pcDNA group,apoptotic rate (11.14±0.83)% vs (19.74±1.14)% and MDA level (277.89±15.46) nmol/mL vs (583.39±10.29) nmol/mL spiked markedly in HG+CHS+pcDNA-circEIF4G2 group (P<0.05) while SOD activity dropped markedly (144.04±13.23) U/L vs (62.98±6.14) U/L,P<0.05. Conclusion Chikusetsu saponin Ⅳa may alleviate high glucose-induced human renal tubular epithelial cell apoptosis and oxidative stress injury. The mechanism is correlated with a suppression of circEIF4G2/miR-379-5p axis.