The effect of aerobic exercise, ozone and mesenchymal stem cells on pain threshold changes in osteoarthritis rats

Acute and chronic stress due to inactivity, especially inactivity due to osteoarthritis can affect pain threshold and painful behaviors; therefore, this study aimed to determine the effect of aerobic exercise, ozone and MSCs on pain threshold changes in osteoarthritis rats.

Forty-five adult male Wistar rats (6-8-week-old), weighing an average of 250-230g, were divided into osteoarthritis (n=40) and healthy controls (n=5). Osteoarthritis were induced by surgery in rats and then divided into 8 groups of 5, including patient control, MSCs, aerobic exercise, ozone, aerobic exercise+ozone, aerobic exercise+MSCs, ozone+MSCs and aerobic exercise+ozone+MSCs. Aerobic exercise was performed for eight weeks at a speed of 16 M/min. MSCs were injected at 1×106 cells/kg into the knees of rats; ozone was also injected into 3 replicates before training with a concentration of 20 μg/ml. Pain threshold was measured by hot-plate test and its significance level was considered 0.05.

Pain threshold in the osteoarthritis patient group was significantly reduced compared to the healthy group (P=0.001). There was a significant increase in pain threshold in cell therapy (P=0.003), ozone therapy and aerobic exercise groups (P=0.0001). While the peak of this increase was seen in MSCs+aerobic exercise (P=0.02).

Induction of osteoarthritis leads to a decrease in pain threshold. Although aerobic exercise, ozone and MSCs play an important role in controlling acute pain due to osteoarthritis by increasing the pain threshold, the maximum analgesic effect is in the interaction of aerobic exercise+MSCs.