The healing effects of L-carnitine and spongostan on cartilage defect in rat model

•Inflammation caused by osteochondral damage affects the mitochondria, causing a decrease in ATP synthesis and cellular activity.•This prospective experimental study was conducted at the experimental animal application.•In our study, we investigated the healing effects of L-carnitine and spongostan on osteochondral lesions (OCL) formed in the rat femoral intercondylar region and found that spongostan administration alone was insufficient for OCL healing, but combined administration of spongostan with L-carnitine performed OCL healing at a level close to healthy cartilage.•When it is planned to apply a scaffold to a cartilage-damaged area, we can recommend adding L-carnitine in addition to the scaffold because of the positive contribution it offers to cartilage healing.•Our study will contribute to the literature as a pioneering study for research in which the effect of the combined administration of different agents related to cartilage healing will be evaluated. We aimed to determine the effect of L-carnitine and spongostan on cartilage healing in an experimental animal model with a full-thickness cartilage defect. In the study 32 Sprague–Dawley rats were divided into four groups in equal numbers. A cartilage defect with a diameter of 1 mm and a depth of 3 mm was created in the femoral intercondylar region of rats in groups A, B, and C. Group A received no treatment in the defective area. Group B received treatment with spongostan. Group C received treatment with spongostan soaked in L-carnitine. Group D served as the healthy control group. The rats were euthanized 6 weeks after the treatment. Histological evaluation of the condyles was done with the modified Mankin scoring. In the histopathological imaging of the cartilage structure, it was observed that in group A, there was complete disorganization and cellular structure was completely absent up to the subchondral bone. In group B, moderate structural improvement, partially intact appearance in border integrity and mostly diffuse hypercellularity were observed. In group C, a near-normal healing, a completely intact appearance in boundary integrities and normal or hypercellularity in cellular structure were observed. The total score of the modified Mankin decreases numerically from A to D. There was no statistically significant difference observed between the A-B (p = 0.176), C-D (p = 0.145), and C-B (p = 0.580) groups, while significant differences were detected between the A–C (p = 0.004), B–D (p = 0.