Factors that influence outcome in experimental osteoarthritis.

OBJECTIVE: Osteoarthritis (OA) is the most common joint disease but an effective pharmacological therapy has not been developed yet. To identify targets for treatment and ways to interfere with OA development and progression both spontaneous and induced OA models are still needed. In this narrative review it is discussed what variables can be identified that lead to variation in OA animal model studies.
DESIGN: Literature was screened (Pubmed) with the following terms; OA animal models in combination with species, age, strain, gender/sex, housing, diet, fighting, circadian rhythm, transgenic. Relevant articles were selected and additional papers were searched for and read for specific subtopics.
RESULTS: Studies with OA models are subject to a multitude of variables, stimuli and conditions that can influence the outcome of an animal experiment. Outcome will depend on amongst others; the model used, species and strain, age, gender, diet, housing conditions, circadian rhythm, timing of intervention, stress levels and activity. Variations in these variables can account for discrepancies between OA model experiments, intervention studies and conclusions.
CONCLUSION: To improve OA animal model research, investigators should be aware of all the stimuli and conditions that can interfere with disease development and disease intervention and take these into account in their study design and execution.