Research Paper|Volume 12, Issue 2|pp 1087—1103

Metformin attenuates cartilage degeneration in an experimental osteoarthritis model by regulating AMPK/mTOR

Xiaofeng Feng¹, Jianying Pan¹, Junyan Li¹, Chun Zeng¹, Weizhong Qi¹, Yan Shao¹, Xin Liu¹, Liangliang Liu¹, Guozhi Xiao², Haiyan Zhang¹, Xiaochun Bai^1,^3,⁴, Daozhang Cai¹

¹Department of Orthopedics, Academy of Orthopedics Guangdong Province, Orthopedic Hospital of Guangdong Province, Guangdong Provincial Key Laboratory of Bone and Joint Degenerative Diseases, The Third Affiliated Hospital of Southern Medical University, Guangzhou 510280, China
²Department of Biology and Shenzhen Key Laboratory of Cell Microenvironment, South University of Science and Technology of China, Shenzhen 518055, Guangdong, China
³Key Laboratory of Mental Health of the Ministry of Education, Department of Cell Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, Guangdong, China
⁴Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou 510005, China

* Equal contribution

Received: May 16, 2019Accepted: December 23, 2019Published: January 16, 2020

https://doi.org/10.18632/aging.102635

Copyright: © 2020 Feng et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Abstract

Background: It is generally thought that the occurrence and progression of osteoarthritis (OA) results from multiple causes, including degradation and destruction of the cartilage matrix and aging of chondrocytes. Metformin is a first-line drug for the treatment of diabetes, and has great potential for the treatment of other disorders. However, the role of metformin in OA is unknown.

Results: Metformin displayed a protective effect against OA. There were lower OARSI scores and fewer MMP-13-positive cells in DMM mice and cartilage explants after treatment with metformin. In addition, metformin treatment decreased p16^INK4a levels in OA chondrocytes, and enhanced polarization of AMPK and inhibition of mTORC1 in OA mice and chondrocytes in a dose-dependent manner.

Conclusions: Metformin effectively alleviated cartilage degradation and aging through regulation of the AMPK/mTOR signaling pathways, suggesting that it could be an effective treatment for OA.

Methods: The effects of metformin on cartilage degradation and chondrocyte aging was determined in a destabilization of the medial meniscus (DMM)-induced OA mouse model and in IL-1β-treated mouse chondrocytes and cartilage explants. Articular cartilage degeneration was graded using the Osteoarthritis Research Society International (OARSI) criteria. Immunostaining, RT-PCR, and western blot analyses were conducted to detect the relative expressions of protein and RNA.