Thesis, COLLÉGIALITÉ

Abstract

Background: Among the many structures of the knee joint, the function of IFP remains unclear. It seems to be involved in biomechanics, inflammatory response, blood supplement for other knee structures, proprioception, and it is also an potential reservoir of stem cells. Osteoarthritis (OA) has developed into a disease with high incidence. IFP has been thought to be more and more considered in OA pathobiology. At present, there is still no perfect treatments for OA, and both conservative treatment and surgery still need to be improved. Regenerative therapy is popular in musculoskeletal therapy and has been used by veterinarians for tendon repair. But we still don’t know how does it work on IFP. So this paper aimed to conduct a systematic review on PRP in regenerative therapy in house tendon, and to access the pathobiology of IFP in OA. Methods: Firstly, a systematic review is conducted to provide basic knowledge on whether regenerative medicine can be applied to OA treatment. For the experimental part, histological staining was used to assess pathobiology of IFP in traumatic OA and age-related OA. Traumatic OA was induced by anterior cruciate ligament transection and partial meniscectomy (ACLT and pMMX). Haematoxylin Eosine Safran (HES) was used to assess the morphology of the fat pad, and score intima, fibrosis, vascularization, and inflammatory infiltration. Toluidine blue O - Fast Green (TBOFG) staining was used to characterize the presence of proteoglycans in the interstitial area of the fat pad. Picrosirius red-weigert’s hematoxylin (PSR) staining enabled to assess collagen content and organization. Results: There is a lot of literature on regenerative medicine for horse tendon injuries, however, literature lacks definitive evidence of efficiency for regenerative medicine. There is on statistical difference on the score of Intimal hyperplasia, Proteoglycans, Sub-intimal fibrosis and Vascularity between young and eldly sheep. While in traumatic OA, they rise early in the disease (4w-6w) and fall down at 28w. The same trend was observed for the opposite leg, although there was no statistical difference. At 28w, the score of PSR (| RF0 - RF30 |) was the highest compared with both control and early stage of the disease (4w-6w). Cartilages were found in some of the traumatic OA they were not present in in uninjured sheep. 1 Conclusions: Surgery or trauma can cause acute stress of IFP and may be a risk factor for chondrodifferentiation of IFP. This stress degrades over time and the collagen becomes parallel in the late stage. ACLT and pMMX-induced traumatic OA did not induce significant compensatory or decompensated response in contralateral leg. The natural incidence of pathological changes of OA in IFP is low in elderly sheep.