Effect of oral vitamin K2 use on knee osteoarthritis progression in an experimentally created osteoarthritis model in rats

AIM: Vitamin K is the name given to a group of fat - soluble vitamins. In the literature, many studies have been conducted on vitamin K deficiency and osteoarthritis. However, it has not yet been clarified through which vitamin K type the effect on osteoarthritis is mediated. In our study, we hypothesized that this effect may be related to vitamin K2 and aimed to examine its effect on knee osteoarthritis progression. MATERIALS AND METHODS: 24 male Sprague Dawley rats were included in the study. The rats were divided into 3 equal groups: sham group, control (osteoarthritis) group, and treatment group. Sterile saline was applied intraarticularly to the right knee of the sham group and Monosodium Iodoacetate (MIA) molecule was applied intraarticularly to the right knee of the control and treatment groups to create an osteoarthritis model. In addition to the standard diet, 8 micrograms (µg) / day of vitamin K2 was given orally to the rats in the treatment group. After 28 days of follow-up, the rats were sacrificed. Right knee articular cartilage was examined histologically with Hematoxylin - Eosin and Safranin O and immunohistochemically with type II collagen alpha 1 and Matrix Metalloproteinase - 13 (MMP - 13). Mankin was used as a histologic scoring system and H - Score scoring system was used for the evaluation of immunohistochemical data. RESULTS: Histologic examinations showed that the cartilage was more regular and the cartilage thickness was higher in the treatment group than in the control group and there were no synovial tissue remnants. Mankin score data showed significantly lower results in the treatment group (4.25 ± 0.83) compared to the control group (11.10 ± 0.83). Immunohistochemical examinations revealed more intense type II collagen staining and less MMP-13 staining in the treatment group compared to the control group. According to H-Score data, type II collagen level was significantly higher in the treatment group (35.00 ± 7.60) compared to the control group (6.30 ± 2.31), while MMP-13 level was significantly lower in the treatment group (28.80 ± 8.30) compared to the control group (71.30 ± 2.31). CONCLUSION: It was found that OA progression could be slowed down by oral vitamin K2 administration in the OA model induced by MIA in rats. This is the first study in which vitamin K2 was found to be effective on OA progression. Keywords: Vitamin K2, osteoarthritis, rat.