Standardized Instability-induced Animal Models for Preclinical Studies of Osteoarthritis

Summary

This protocol aims to establish suitable animal models for researching osteoarthritis.

Abstract

As the most prevalent joint disorder worldwide, knee osteoarthritis (OA) represents a significant global health burden, prompting extensive research into its pathogenesis and treatment strategies. Despite numerous studies, standardized methodologies for model establishment remain lacking. Thus, to address this gap, we present comprehensive, reproducible protocols for developing instability-induced animal models of osteoarthritis, specifically the Destabilization of the Medial Meniscus (DMM) model in mice and the Medial Meniscus Tear (MMT) model in rats. Furthermore, we describe a straightforward and easily implementable procedure for assessing postoperative pain thresholds and spatial gait stability, aimed at promoting methodological consistency in preclinical OA research. Histological and behavioral validation confirmed the success of both models, as Osteoarthritis Research Society International (OARSI) scores were markedly elevated, stride length was significantly altered, and mechanical pain thresholds were substantially reduced in the DMM and MMT groups compared with controls, indicating pronounced joint degeneration and hypersensitivity. These validation outcomes underscore the reproducibility and translational relevance of the two models. Thus, by providing detailed video documentation, this work promotes procedural standardization and facilitates inter-laboratory consistency, thereby enhancing the reliability and comparability of OA research outcomes.

Introduction

Osteoarthritis (OA) is a highly prevalent degenerative joint disorder and one of the leading causes of disability worldwide^1,2. Despite extensive research, the development of effective disease-modifying OA drugs (DMOADs) has been relatively slow³. It is now widely acknowledged that OA is a multifactorial disease involving complex pathological changes across multiple peri-articular tissues, including articular cartilage, subchondral bone, tendons, and synovium^4,5. Effective preclinical research on the diverse pathological process....

Protocol

All experimental procedures were conducted in accordance with the guidelines of the Animal Ethical and Welfare Committee of Zhejiang Chinese Medical University and were approved under the protocol number IACUC-20251020-11. For the DMM surgery, male C57BL/6 mice aged 10-12 weeks were used, while male Sprague-Dawley rats weighing 200-225 g were selected for the MMT procedure. All animals were housed under specific pathogen-free (SPF) conditions and allowed a one-week acclimatization period prior to experimentation. Standard husbandry conditions were maintained, with food, water, and bedding replaced at least twice weekly to ensure animal welfare and experimental consist....

Results

Characterization and validation of the DMM OA mouse model
After a 1 week acclimatization period, the DMM-induced osteoarthritis (OA) model in mice was established following the procedure illustrated in Figure 1. Pathological and behavioral assessments were performed two weeks post-surgery. As shown in Figure 2A, the most pronounced degenerative changes were localized to the medial femorotibial joint. The extent of cartilage degeneration was .......

Discussion

This protocol provides a standardized framework for the induction and evaluation of two widely used surgical OA models. These models are particularly valuable because they closely replicate the pathophysiological features of human post-traumatic OA, thereby offering strong translational relevance. The DMM model involves transection of the medial meniscotibial ligament, whereas the MMT model entails a direct tear of the medial meniscus. In our laboratory, the DMM procedure is routinely performed in mice, as the medial men.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Gait analysis system	Shanghai Xin Ruan Information Technology Co., Ltd	XR-FP202
Liposic			ophthalmic ointment
Mice	Nanjing Institute of Model Animals	c57/bl6
Pain testing system	Shanghai Xin Ruan Information Technology Co., Ltd	XR-XZD	electronic von Frey anesthesiometer
Rat	Nanjing Institute of Model Animals	S/D