Grape seed proanthocyanidins extracts promote apolipoprotein A-I mRNA expression in HepG2 cells under experimental sugar and high-sugar conditions

Q. Zhai, N. Zhong*, H.Q. Gao**, B.Y. Li**, B. Jiang***

Department of Intensive Care Unit, Qilu Hospital of Shandong University, Jinan 250012 (China)
*Diagnostic Institute of Shandong University School of Medicine, Jinan 250012 (China)
**Department of Geriatrics, Qilu Hospital of Shandong University, Jinan 250012 (China)
***Department of Urology, Qilu Hospital of Shandong University, Jinan 250012 (China)

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• Pharmacology

Abstract. – Objectives: In this study, we investigated the effect of grape seed proanthocyanidins extracts (GSPE), which have been proved to have anti-oxidative and anti-aging functions, on the expression of apoA-I at mRNA level of HepG2 cells in vitro under the experimental conditions of high-sugar and sugar.

Materials and Methods: Cell viability was measured by sulforhodamine B (SRB). The apoA-I mRNA expression was assayed by real-time fluorescence quantitative polymerase chain reaction. Firstly, HepG2 cells were incubated in 10% inactivated newborn calf serum in Dulbecco’s Modified Eagle Medium (DMEM). Next, cells were incubated with high-sugar and sugar serum-free medium, and added different concentration of GSPE (2.5, 5 and 10 μg/ml) for more than 24 hours, and thereafter, investigated whether GSPE can promote more apoA-I expression in HepG2 cells under the experimental conditions of high-sugar and sugar.

Results: In this experiment, HepG2 cells were incubated with high-sugar and sugar serum-free medium, and HepG2 cells incubated with high-sugar medium produced less apoA-I at mRNA level. The difference was significant (p < 0.05). When HepG2 cells were incubated with GSPE at concentration of 20 μg/ml or above for about 4 hours, cell viability measured by SRB was lower than 50%. However, cell viability of HepG2 cells incubated with GSPE at concentration of 10 μg/ml or below was higher than 70%. Therefore, we chose the HepG2 cells incubated with GSPE concentration of 2.5, 5, 10 μg/ml to observe the effect of GSPE on the mRNA expression of apoA-I. After incubated with GSPE, the apoA-I expression of HepG2 cells were significantly elevated at mRNA level compared to that of high sugar control (p < 0.05). Moreover, this action of GSPE showed dose dependent, and the dose of 2.5 μg/ml was optimal.

Conclusions: GSPE (concentration of higher than 20 μg/ml) could inhibit HepG2 cell survival, and in HepG2 cells, endogenous apoA-I was significantly suppressed following 24h of exposure to high concentrations of glucose. Meanwhile GSPE could promote expression of apoA-I dose dependently at mRNA level when its concentration was lower than 10 μg/ml.

Corresponding Author: Hai-qing Gao, MD; e-mail: haiqing.gao.sd@gmail.com

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