Deterioration in sensible joint innervation as a possible cause for the development of osteoarthritis. An animal study in rats

In the present study we investigated the influence of an altered sensible j oint innervation on the development of knee osteoarthritis in a wistar rat model of osteoarthritis. Capsaicin (8-methyl-N-vanillyl-6-noneamide) mediat ed partial sensible knee joint denervation was performed in a group of 16 m ale wistar rats. Twelve rats without alterations of the sensible knee joint innervation served as controls. Tn both groups, halft of the rats underwen t strenuous running exercises (total running load of 20 km) in a running wh eel by intracranial self-stimulation, while the other half did not have any running load. In rats without running, there were no histological sings of knee osteoarth ritis according to the Mankin score. In contrast, in rats running a total o f 20 km significant osteoarthritis changes were observed. Hereby, in rats w ithout altered sensible knee joint innervation, osteoarthritis was mostly c lassified as mild or moderate, while severe osteoarthritis was the predomin ant finding in the knee joints of the rats with partial sensible knee joint denervation; In conclusion, our study gives strong evidence for the hypothesis: that an altered sensible joint innervation works as a contributing factor in the de velopment of osteoarthritis.