The efficiency of intra-articular injection of silver nanoparticles (AgNPs) on repair of experimentally induced avascular meniscal tear in dogs

Meniscal tears in the inner avascular area have been reported as a common cause of disability in dogs that associated with failure of healing process due to their limited vascularity. In spite of various sterategies were reported for treatment of such tears, their clinical use was limited. Therefore, different biomaterials have been assessed to stimulate regeneration of avascular meniscal tears. Currently, silver nanoparticles (AgNPs) enormously involved in biomedicine including tissue regeneration, drug delivary, and antibacterial applications. Thus, AgNPs was fabricated in the present study to investigate its potential to induce and support meniscal healing process in an avascular meniscal tear model. The nanomaterial was synthesized and characterized using transmission electron microscope (TEM). Next, a full thickness longitudinal meniscal tear was created in the avascular zone and either left empty or treated with AgNPs.  Animals were monitored clinically at weeks 3, 6, 9, and 12 weeks after surgery for lameness parameters including lameness during walking, pain on manipulation, range of motion, and functional disability. Additionally, the harvested menisci were examined macroscopically and histologically at 4, 8, and 12 weeks. The designed material revealed improved clinical outcomes compared to control group. The gross and histological observations proved that the meniscal healing was stimulated in the AgNPs-treated group in comparison to control one, where the AgNPs-treated tear sites were filled with reparative tissue. In conclusion, AgNPs nanomaterial has a promoting effect on the process of meniscal tissue healing in the avascular region, proving that AgNPs is a promising material for meniscal tissue regeneration.