A evolução da osteoartrite em relação ao conteúdo de proteoglicanos e densidade das fibras colágenas em joelhos de ratos submetidos à transecção do ligamento cruzado anterior.

Abstract

Osteoarthritis is a chronic disease that affects the synovial joints causing degeneration of the articular cartilage and, as a consequence, causes losses in the quality of life of the affected ones. In this context, studies with experimental models of osteoarthritis are of fundamental importance both for a better understanding of joint pathophysiology and to verify the efficacy of new treatment methods. Thus, the objective of this study was to evaluate the evolution of the degenerative process in the cartilage of the knees of rats, regarding loss of proteoglycan content and alteration in the density of collagen fibers, in an experimental model of osteoarthritis by transection of the anterior cruciate ligament (TACL) in four moments after injury (3, 6, 9 and 12 months). For this purpose, 25 male rats (Wistar) at 3 months of age were divided into 5 groups: Control Group (C), Group Osteoarthritis 3 months (OA3), Group Osteoarthritis 6 months (OA6), Group Osteoarthritis 9 months (OA9) and Group Osteoarthritis 12 months (OA12). The animals in the control group did not undergo any intervention and were euthanized at 9 months of age. The animals of the osteoarthritis groups were euthanized in their respective times after transection of the anterior cruciate ligament. To evaluate the progression of the degenerative process, analyzes of the proteoglycan content and quantification of the density of the total collagen fibers were performed. As for the statistical analysis, the normality test of Shapiro Wilks was applied, in which in the data considered parametric the post-test ANOVA with Post Hoc Tukey (p ≤ 0.05) was applied and in the data considered non-parametric the post- Kruskal-Wallis test (p ≤ 0.05). The results demonstrated a gradual reduction in the content of proteoglycans throughout the evolution of osteoarthritis. The groups OA3 and OA6 presented lower amount of proteoglycans in relation to group C, but did not present any difference between them. The OA9 group had a lower amount of proteoglycans compared to groups C, AO3 and OA6. Finally, the OA12 group showed a greater reduction of the proteoglycan content in relation to all groups. Moreover, the analysis of the density of the collagen fibers showed a gradual reduction of the density of collagen fibers throughout the evolution of the degenerative process, but without significant difference between the OA9 and OA12 groups. The groups OA3 and OA6 showed a difference between group C, but did not present any difference between them. On the other hand, the OA9 group presented a difference between all groups, except for the OA12 group. Therefore, it was concluded that OA evolved slowly and gradually in the experimental model by TLCA, demonstrated by the decrease in both the proteoglycan content and the density of the collagen fibers in the OA3 group, being higher in the groups with longer exposure to the stimulus.