Alleviation of synovitis caused by joint instability with application of platelet-rich plasma.

•PRP alleviate the effusion, edema and thickening of the synovium when OA occurs.•Histologically, PRP alleviate synovitis by suppressing the fibrosis and vascularization of the sub-lining tissue.•The concentration of IL-1β with osteoarthritis declines when PRP is applied, which alleviates the topical inflammation.