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.

Plain Language Summary

Metformin Reduces Oxidative Stress and Helps Bone-Forming Cells Affected by Corticosteroids

Long-term use of corticosteroids can cause various bone diseases. This happens because corticosteroids disrupt the balance of energy processes in the body, leading to increased oxidative stress and production of harmful molecules called reactive oxygen species (ROS). These changes prolong inflammation, cause cell death, and affect the development of certain cells like mesenchymal stem cells (MSCs) and osteoclasts, which are involved in bone formation. The purpose of this study was to examine how corticosteroids and a diabetes drug called metformin affect MSCs. Metformin is known to have antioxidant properties, meaning it can reduce oxidative stress by inhibiting an enzyme that promotes the production of ROS. We collected primary bone marrow MSCs from 20 mice. They assessed how prednisolone (a type of corticosteroid) affects cell growth, oxidative stress, and bone formation. Metformin was then tested to see if it could counteract the negative effects of prednisolone. Different concentrations of metformin (1, 10, 100 µM) were examined along with 3 ng/mL prednisolone. Cytokine levels, which are signaling molecules in the body, were also measured. Prednisolone at 3 ng/mL significantly reduced cell growth, but 10 µM metformin was able to restore it. Prednisolone increased oxidative stress, but metformin reduced this stress in a concentration-dependent manner, especially at 100 µM. Prednisolone also impaired bone formation, but metformin improved it at concentrations of 10 and 100 µM. Prednisolone increased the expression of the inflammatory cytokine interleukin-1β (IL-1β), but metformin suppressed it. On the other hand, prednisolone reduced the levels of other cytokines, IL-6 and monocyte chemotactic protein-1. Corticosteroids decrease the bone-forming potential of MSCs by increasing oxidative.