The healing effect of soybean and avocado mixture on knee cartilage defects in a dog animal model

Avocado/soybean mixture is shown to have a positive effect on cartilage preservation in arthritis. This study was undertaken to study the healing effect of soybean and avocado mixture on full-thickness knee cartilage defect, which were treated by microfracture in dog. Twenty-two outbred male dogs (44 knees) were divided into two equal groups. In both groups, a 1×1 cm fullthickness lesion was created in medial femoral condyle of each knee eliminating the calcified cartilage, which was curetted down to the subchondral bone. In the left knee, a microfracture was produced. The right knee was closed without performing any microfracture. Half of the dogs in each group received 300 mg of avocado/soybean mixture in one capsule, and the remaining animals in each group received a placebo as an empty capsule each day. There were four treatment groups, including a combined group undergoing microfracture and receiving avocado/soybean, microfracture group undergoing microfracture and receiving placebo, avocado/soybean group that did not undergo microfracture but received avocado/soybean, and a control group that did not undergo microfracture and received placebo. There was no postoperative limitation of motion. After 12 weeks, all dogs were euthanized, and the articular cartilage tissues were studied according to International Cartilage Repair Society (ICRS) visual histological assessment scale. There were no significant differences in cartilage surface histology, cell distribution, and cell viability among the four groups. Subchondral bone histology was normal in six specimens in the control and avocado/ soybean groups. One in the microfracture group and two in the combined group achieved normal histology. Four samples in each of the control and avocado/soybean mixture and combined groups, and nine samples in the microfracture group depicted increased remodeling of subchondral bone. Calcified cartilage zones were normal in six and seven samples in the control and the avocado/soybean mixture groups, respectively. There were no samples with normal histological appearance in the microfracture group.We did not observe any additive effect of avocado/soybean mixture to microfracture induced repair tissue in this study as evaluated by ICRS visual histological assessment scale.