Resveratrol protects against high glucose-induced steroidogenesis and apoptosis in murine granulosa cells.

Resveratrol (Res) is a polyphenolic compound that exhibits a diverse array of biological effects. Herein, we detected the ability of Res on murine granulosa cells (GCs) against impaired steroidogenesis and apoptotic death in response to high glucose levels. Ovarian GCs were harvested from C57BL/6 mice and cultured in steroidogenic media supplemented with follicle-stimulating hormone (FSH, 30 ng/mL), Res (50 µmol/L), and low or high glucose concentrations (5 mM or 30 mM). After culture for 24 h, cell supernatants were harvested and the levels of progesterone and estradiol therein were measured. Also, caspase-3 activity and the expression of genes associated with apoptosis and steroidogenesis were assessed. High-glucose treatment suppressed steroidogenesis in this assay system, resulting in the impaired expression of steroidogenesis-related genes including Cyp11a1, Cyp19a1, 3ßHSD, and StAR and a concomitant decrease in progesterone and estradiol production. Cells exposed to high glucose also exhibited apoptotic phenotypes characterized by Bax upregulation, Bcl-2 downregulation, and increased caspase-3 activity levels. However, Res treatment was sufficient to reverse this high glucose level-induced apoptotic and steroidogenic phenotypes with improving progesterone and estradiol production, and these maybe related the effects of Res on Cyp11a1, Cyp19a1, 3ßHSD, and StAR expressions. These data suggested that Res is well suited to overcoming the negative effects of hyperglycemia of GC functionality.

Sonodynamic therapy inhibits palmitate-induced beta cell dysfunction via PINK1/Parkin-dependent mitophagy.

In type 2 diabetes mellitus (T2DM), the overload of glucose and lipids can promote oxidative stress and inflammatory responses and contribute to the failure of beta cells. However, therapies that can modulate the function of beta cells and thus prevent their failure have not been well explored. In this study, beta cell injury model was established with palmitic acid (PA) to simulate the lipotoxicity (high-fat diet) found in T2DM. Sonodynamic therapy (SDT), a novel physicochemical treatment, was applied to treat injured beta cells. We found that SDT had specific effects on mitochondria and induced transient large amount of mitochondrial reactive oxygen species (ROS) production in beta cells. SDT also improved the morphology and function of abnormal mitochondria, inhibited inflammatory response and reduced beta cell dysfunction. The improvement of mitochondria was mediated by PINK1/Parkin-dependent mitophagy. Additionally, SDT rescued the transcription of PINK1 mRNA which was blocked by PA treatment, thus providing abundant PINK1 for mitophagy. Moreover, SDT also increased insulin secretion from beta cells. The protective effects of SDT were abrogated when mitophagy was inhibited by cyclosporin A (CsA). In summary, SDT potently inhibits lipotoxicity-induced beta cell failure via PINK1/Parkin-dependent mitophagy, providing theoretical guidance for T2DM treatment in aspects of islet protection.