STREPTOZOTOCIN-INDUCED DIABETES DECREASES SUBSTANCE-P LEVELS IN EXPERIMENTAL ARTHRITIS IN THE RAT KNEE

Diabetic patients with sensory neuropathy are predisposed to disorders of the musculoskeletal system. It has been postulated that altered ne urogenic inflammation, involving the neuropeptide substance P, may pla y a part in this phenomenon. We investigated the effect of streptozoto cin-induced (STZ) diabetes on the development of an antigenic (mBSA) m onoarthritis in the rat with particular reference to changes in substa nce P levels in dorsal root ganglia (DRG) and knee joint synovium. We found that STZ-induced diabetes of 24 weeks duration reduced the subst ance P content of L(4)/L(5) DRG and knee joint synovial tissue. Induct ion of mBSA arthritis in diabetic rats resulted in diminished increase s in synovial substance P and knee joint swelling compared to non-diab etic arthritic controls. The results show that chronic STZ diabetes re duces neurogenic inflammatory responses in the rat knee which may rend er the joint more susceptible to arthritic attack.