Treatment of Osteochondral Femoral Head Defect by Human Umbilical Cord Mesenchymal Stem Cell Sheet Transplantation: An Experimental Study in Rats.

Abstract

Articular cartilage is limited in self-repair following injuries due to avascular, lymphatic, and nerve absence. Recent treatments for cartilage injuries, such as physical therapy, anti-inflammatory medication, chondrocyte implantation, and joint replacement, still have limitations. This study aimed to evaluate the treatment efficacy of human umbilical cord-derived mesenchymal stem cell sheet (UCMSCS) transplantation in rat models of the osteochondral femoral head defect. Models of osteochondral femoral head defect were produced in rats by drilling in order to reach the femoral bone tissue through the cartilage layer. Then, UCMSCS was implanted in the created cartilage lesion. The treatment efficacy was monitored by X-ray imaging. The cartilage regeneration was evaluated based on the hematoxylin and eosin staining, and proteoglycan accumulation was detected by staining Safranin O and Fast Green. The physiological, weight, or movement activity of rats were recorded during the treatment period. UCMSCS transplantation showed positive effects on the cartilage regeneration in osteochondral femoral head defect grade 4 (according to ICRS score/grade). Particularly, after 12weeks of implantation of UCMSCS, the defect was filled with hyaline cartilage-like cells and accumulated a large density of proteoglycan. The osteochondral defect score significantly increased in the treated rats compared to the untreated rats (11.67±0.6 and 9.67±0.6, respectively) (p<0.05). The histological score also increased in treated rats compared to untreated rats (21.33±1.53 vs. 18.00±1.00) (p<0.0001). The accumulation of proteoglycan was higher in treated rats (20.50±2.23) than untreated rats (5.38±0.36) (p<0.05). There was no change in the physiological activities between treated and untreated rats recorded during the study. MSCS transplantation could promote regeneration in advanced cartilage injury.