Metformin Modulates Oxidative Stress in Murine Mesenchymal Stem Cells In Vitro and Alleviates Corticosteroid-Induced Inflammation and Impairment of Bone Formation.

Abstract

Background: Long-term use of corticosteroids is a known risk factor for various bone diseases. Corticosteroids disrupt the balance between oxidative and glycolytic energy metabolism, increase oxidative stress and reactive oxygen species (ROS) associated with prolongation of inflammation, cell apoptosis, deficits in mesenchymal stem cells (MSCs), and osteoclast differentiation. Metformin, a drug for diabetes, has antioxidant properties by inhibiting nicotinamide adenine dinucleotide phosphate oxidase, which promotes the production of ROS.

Purpose: We sought to evaluate the effects of corticosteroid and metformin administration on MSCs in vitro.

Methods: Primary bone marrow MSCs were collected from 20 mice. We evaluated prednisolone's effects on cell proliferation, oxidative stress, osteogenic differentiation, and mineralization, followed by metformin's effect on corticosteroid-induced reduction in bone formation. Metformin (1, 10, 100 µM) was tested with prednisolone 3 ng/mL. Cytokines were assessed by Luminex.

Results: Prednisolone at 3 ng/mL significantly reduced cell proliferation, while 10 µM metformin restored it. Prednisolone increased oxidative stress and was reversed by metformin in a concentration-dependent manner, particularly at 100 µM. Osteogenic differentiation and mineralization were significantly impaired with prednisolone but improved with metformin at 10 and 100 µM. As for inflammatory cytokines, interleukin-1β (IL-1β) expression was increased by prednisolone administration and suppressed by metformin. Conversely, IL-6 and monocyte chemotactic protein-1 were suppressed by prednisolone.

Conclusion: This in vitro study found that corticosteroid-associated decrease in osteogenic potential of murine MSCs was associated with elevated oxidative stress that can be alleviated by metformin; further studies are needed to validate these findings in vivo and with human-derived MSCs.