Objective:
Dexmedetomidine is the pharmacologically active dextroisomer of medetomidine that displays specific and selective a2-adrenoceptor agonism. We have investigated the effects of intraarticular administration of dexmedetomidine in the rat knee joint.
Material and Methods:
Fifty-one mature Spraque-Dawley rats were included in the study. 16.10-3 mol. litre-1 of dexmedetomidine was injected into the right knee joint in Group I rats (n=33). Three rats were sham operated. The rats were sacrificed at 24th h (10 rats), at 48th h (10 rats) and on the 7th day (10 rats). In the second step, 16.10-2 mol. litre-1 dexmedetomidine was administered intraarticularly in 6 rats (Group II).
Results:
Histopathological findings in Group I were a regular synovial membrane at 24. hours; polymorphonuclear leucocytes, mast cells and a regular synovial membrane at 48. hours; mild polymorphonuclear leucocytes, lymphocytes and mild edema on the 7th day. These findings were indicative of a moderate inflammation. In Group II were rare leucocytes, rare lymphocytes along with plenty of mast cells, foci of microcalcifications due to localized trauma and increased leucocytes in the surrounding muscle tissue, thickening of synovial membrane and papillary proliferation on the 7th day. Findings indicative of a moderate inflammation were also encountered on the 7th day with the concentration increased 10 times.
Conclusion:
Caution should be taken when using intra-articular dexmedetomidine for post-operative analgesia. According to our results, we concluded that further research is needed on this topic.
Keywords: intraarticular, rat, dexmedetomidine, analgesia, synovium, cartilage