Catalase prevents estradiol-induced chondrocyte cytotoxicity

Mechanisms of chondrocyte regulated cell death in osteoarthritis: Focus on ROS-triggered ferroptosis, parthanatos, and oxeiptosis

Osteoarthritis (OA) is a common chronic inflammatory degenerative disease. Since chondrocytes are the only type of cells in cartilage, their survival is critical for maintaining cartilage morphology. This review offers a comprehensive analysis of how reactive oxygen species (ROS), including superoxide anions, hydrogen peroxide, hydroxyl radicals, nitric oxide, and their derivatives, affect cartilage homeostasis and trigger several novel modes of regulated cell death, including ferroptosis, parthanatos, and oxeiptosis, which may play roles in chondrocyte death and OA development. Moreover, we discuss potential therapeutic strategies to alleviate OA by scavenging ROS and provide new insight into the research and treatment of the role of regulated cell death in OA.

Sex steroids enhance insulin receptors and glucose oxidation in Chang liver cells

BACKGROUND

The present study was designed to assess the effect of sex steroids (testosterone and 17beta-estradiol) on insulin receptor expression, insulin binding and glucose oxidation in human liver cell line.

METHODS

Non-malignant Chang liver cells were treated with different concentrations of testosterone and 17beta-estradiol dissolved in serum free medium for 24 h to identify the effective dose of both steroids for further studies. Cells with 70-80% confluency were challenged with testosterone (0.1 micromol/l), 17beta-estradiol (0.1 micromol/l) and their combination along with insulin as a positive control for 24 h. After the treatment period, insulin receptor mRNA expression, cell surface insulin binding and (14)C-glucose oxidation were assessed.

RESULTS

Both testosterone and 17beta-estradiol significantly increased the insulin receptor mRNA expression, cell surface insulin binding and (14)C-glucose oxidation compared to basal, but the increase was not at par with the effect of insulin. Compared to individual effects of testosterone and 17beta-estradiol, their combination significantly increased the glucose oxidation similar to that of insulin.

CONCLUSION

It is concluded from the present study that testosterone and 17beta-estradiol can directly enhance insulin receptor mRNA expression, insulin binding and glucose oxidation in Chang liver cells and thereby glucose metabolism.