Purpose: Osteoarthritis (OA) is a progressive, age related disease characterized by the degradation of the cartilage, abnormal bone remodelling, and joint pain eventually leading to disability. Obesity is a major risk for the development of OA in both weight-bearing and nonweight-bearing joints and is linked with a state of low-grade inflammation and increased circulation of fatty acids such as the saturated fatty acids (SFA). Therefore, the current study was to evaluate the chronic impact of high saturated fat feeding on the development of obesity and OA.
Methods: Wistar rats (9-10 weeks old) were fed either a corn starch diet (C) or a SFA diet including, lauric acid (LA), myristic acid (MA), palmitic acid (PA) and stearic acid (SA) or a beef tallow as a high-carbohydrate, high fat diet (H) for a period of 16 weeks. Upon euthanasia, the knee joints were harvested and assessed for alterations to the cartilage and subchondral bone. In addition, in vitro phenotypical changes were also assessed in SFA stimulated human chondrocytes and bovine cartilage explants.
Results: At the time of euthanasia, the rats fed with H, PA and SA diets were notably heavier than that of C diet rats. The rats on H, PA and SA diet showed significant increase in knee cartilage degeneration and decreased bone volume compared to other groups. However, the rats that were fed with LA and MA diet showed a similar cartilage structure as that of the control rats (C). Furthermore, PA and SA stimulation caused increased release of glycosaminoglycans (GAGs) from human chondrocytes and bovine cartilage explants.
Conclusions: These data thus raise the possibility that high levels of circulating SFA can cause adverse effects to the joint health and that the effect of SFA on OA risk also depends on the type of fatty acids present in the diet.