Possible therapeutic effect of combined platelet-rich plasma and stem cells on induced knee osteoarthritis in adult male albino rat: histological and immunohistochemical study

Osteoarthritis (OA) is a degenerative joint disease that results from breakdown of joint cartilage and underlying bone. It is the most common form of arthritis among elderly individuals. The present study aimed to investigate the effect of intra‑articular injection of platelet-rich plasma (PRP) and bone marrow mesenchymal stem cells (BMSCs), both in combination and separately in the treatment of monoiodoacetate (MIA) induced OA in rats. Seventy adult male albino rats were randomly divided into seven groups, 10 rats in each (control, sham control, OA-induced, PRP, BMSCs, PRP+BMSCs and recovery). Histological examination was done using haematoxylin and eosin, alcian blue and Masson’s trichrome stains. Immunohistochemical staining for collagen type II antigen and proliferating cell nuclear antigen (PCNA) was carried out. Measurements of serum interleukin 6 (IL-6) was performed using ELISA. Expression of ACAN gene was done using real-time polymerase chain reaction (PCR) and histomorphometric measurements were analyzed. Radiographs were acquired from the knee joint. Light microscopic examination of articular cartilage (AC) from OA-induced group showed disorganization of chondrocytes, loss of zonation, pyknotic nuclei, empty lacunae and absent tidemark. There was a significant decrease in AC thickness, chondrocytes count, optical density of collagen and proteoglycan content, area percent of collagen II in the matrix in OA group compared to control and sham groups. These degenerative histomorphological alterations were associated with significant increase in serum IL-6 and decrease in ACAN gene expression. Radiographs showed narrowing of joint space and subchondral sclerosis. Intraarticular injection of PRP, BMSCs and PRP+BMSCs improved the previously mentioned alterations. Concomitant administration of PRP+BMSCs showed better effect than using PRP and BMSCs alone. In conclusion, PRP potentiated the effects of BMSCs on the repair of MIA-induced AC damage in rats. Injection of combination of PRP with BMSCs could be considered as a promising therapy for OA in patients.