Effects of naringin on high glucose induced damage in rat H9c2 cardiomyocytes

Objective To investigate the effect of naringin (Nar) on rat H9c2 cardiomyocyte injury induced by high glucose (HG) and its mechanism.

Methods H9c2 cardiomyocytes were cultured in vitro and treated with glucose to establish the cell injury model. Then the cells were randomly divided into 5 groups: a normal control (without any intervention), a model (with 35 mmol·L^–1 glucose treatment for 48 hours), and the low, moderate, and high dose Nar dose groups (with pretreatment of Nar at doses of 5, 10, 20 μmol·L^–1 for 4 hours before 35 mmol·L^–1 glucose treatment for 48 hours). The viability of the each H9c2 cardiomyocyte group was detected with 3-(4,5-dimethyl-2-thiazolyl) -2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay. The cell apoptosis was detected with terminal-deoxynucleotidyl transferase mediated nick end labeling (TUNEL) staining. The expressions of inflammatory factor interleukin-6 (IL-6), nuclear factor kappa-B (NF-κB), endoplasmic reticulum stress (ERS)-related glucose regulated protein 78kD (GRP 78), CCAAT/enhancer-binding proteins (C/EBP)-homologous protein (CHOP) and cysteinyl aspartate specific proteinase 12 (caspase 12) were detected with Western blot.

Results Compared with the control cells, the H9c2 cells of model group showed significantly decreased survival rate (70.36 ± 6.31%) (P < 0.01) but increased apoptotic rate (41.25 ± 7.44%) and expressions of IL-6 (0.34 ± 0.03), NF-κB (1.04 ± 0.10), GRP 78 (0.93 ± 0.65), CHOP (0.52 ± 0.02), and caspase 12 (0.39 ± 0.02) (all P < 0.01). In comparison to the cells of model group, the H9c2 cells with high dose Nar pretreatment demonstrated significantly increased survival rate (92.33 ± 5.64%, P < 0.05) but decreased apoptotic rate (25.0 ± 4.82%), intracellular expressions of GRP 78 (0.57 ± 0.04), CHOP (0.31 ± 0.04) and caspase 12 (0.39 ± 0.02), and down-regulated expressions of IL-6 (0.23 ± 0.03) and NF-κB (0.76 ± 0.06) in dose response manners (P < 0.05 for all)

Conclusion Naringin could significantly alleviate apoptosis induced by high glucose in H9c2 cells and the effect may be related to the inhibited expression of ERS and inflammatory factor NF-κB and IL-6.