Deterioration of sensory joint innervation as an enabling factor for development of arthrosis. An animal experiment study of the rat model

Abstract

In the present study we investigated the influence of an altered sensible joint innervation on the development of knee osteoarthritis in a wistar rat model of osteoarthritis. Capsaicin (8-methyl-N-vanillyl-6-noneamide) mediated partial sensible knee joint denervation was performed in a group of 16 male wistar rats. Twelve rats without alterations of the sensible knee joint innervation served as controls. In both groups, half of the rats underwent strenuous running exercises (total running load of 20 km) in a running wheel 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 osteoarthritis according to the Mankin score. In contrast, in rats running a total of 20 km significant osteoarthritis changes were observed. Hereby, in rats without altered sensible knee joint innervation, osteoarthritis was mostly classified as mild or moderate, while severe osteoarthritis was the predominant 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 development of osteoarthritis.