Introduction: Systemic sclerosis (SS) is an autoimmune disorder with high morbidity. It is characterized by chronic inflammation and fibrosis. The articular manifestations of SS were reported in many cases.
Aim of the Work: To explore novel mechanisms involved in systemic sclerosis associated arthritis and to compare the therapeutic effects of the mesenchymal stem cells (BM-MS) versus their conditioned medium (MS-C) on knee joint arthritis associated in a model of systemic sclerosis in rats.
Materials and Methods: Forty rats were divided into group I (Control), group II (SS-associated arthritis) and group III (Treated group). Group III was further arranged into subgroup III-a (BM-MS treated group) and subgroup III-b (MS-C treated group). Four weeks from the last injection in all subgroups, excision of the entire knee joints was done to be processed for the histological and immunohistochemical study.
Results: Group II revealed disturbed histological structure of the articular cartilage, subchondral bone and synovium. Surface irregularities, clefts and superficial erosion of the cartilage were noticed. Degenerated subchondral bone matrix was observed. The synovial membrane showed vascular congestion, edema and inflammatory cellular infiltration. Moreover, there was a significant decrease in the articular cartilage and subchondral bone thickness and in collagen content of the matrix of the articular cartilage. The synovial membrane showed marked subintimal collagen deposition and a significant increase in the immuno-expression of urokinase plasminogen activator (UPA). In contrast, group III showed improvement of all above mentioned parameters which were highly marked in subgroup III-b comparing to subgroup III-a.
Conclusion: MS-C had better therapeutic effects on SS-associated knee arthritis than BM-MS.