The role of oxidative stress on degeneration of rotator cuff enthesis-An analysis of the effect of an anti-oxidant treatment

Abstract

PurposeRotator cuff degeneration is one of the multiple factors that lead to rotator cuff tear, but the mechanism of degeneration still remains unclear. Last year, we reported that an antioxidant enzyme, Superoxide dismutase 1 (Sod1), deficiency in mice induced degeneration changes in supraspinatus tendon enthesis, recapitulating the human rotator cuff degeneration. In this study, we analyzed the effect of antioxidant treatment for the degeneration changes to confirm the link between oxidative stress and rotator cuff degeneration.MethodsWe administered Vitamin C (1%) or vehicle in drinking water to wild-type (WT) and Sod1-/- male mice from 12 weeks of age for 8 weeks (N = 3-4 / each group). At 20 weeks of age, we made histological sections of supraspinatus enthesis and performed haematoxylin-eosin and toluidine blue staining. We analyzed the sections using a quantitative histologic evaluation (Koike et al., JOR 2005).ResultsIn vehicle drinking group, Sod1-/- mice showed a decrease in the evaluation parameters, number of chondrocytes, the percentage of aligned chondrocytes, the area of fibrocartilage and spatial arrangement collagen fibers, compared to WT mice. Furthermore, in Sod1-/- mice, vitamin C treatment significantly increased these parameters compared to vehicle group and improved to the same level as WT mice. In WT mice, no difference was observed between vitamin C and vehicle group.ConclusionSod1-/- mice showed decreases of histologic evaluation parameters and vitamin C treatment improved the reduction of these parameters. These results suggest that oxidative stress induced degeneration of supraspinatus enthesis. PurposeRotator cuff degeneration is one of the multiple factors that lead to rotator cuff tear, but the mechanism of degeneration still remains unclear. Last year, we reported that an antioxidant enzyme, Superoxide dismutase 1 (Sod1), deficiency in mice induced degeneration changes in supraspinatus tendon enthesis, recapitulating the human rotator cuff degeneration. In this study, we analyzed the effect of antioxidant treatment for the degeneration changes to confirm the link between oxidative stress and rotator cuff degeneration. Rotator cuff degeneration is one of the multiple factors that lead to rotator cuff tear, but the mechanism of degeneration still remains unclear. Last year, we reported that an antioxidant enzyme, Superoxide dismutase 1 (Sod1), deficiency in mice induced degeneration changes in supraspinatus tendon enthesis, recapitulating the human rotator cuff degeneration. In this study, we analyzed the effect of antioxidant treatment for the degeneration changes to confirm the link between oxidative stress and rotator cuff degeneration. MethodsWe administered Vitamin C (1%) or vehicle in drinking water to wild-type (WT) and Sod1-/- male mice from 12 weeks of age for 8 weeks (N = 3-4 / each group). At 20 weeks of age, we made histological sections of supraspinatus enthesis and performed haematoxylin-eosin and toluidine blue staining. We analyzed the sections using a quantitative histologic evaluation (Koike et al., JOR 2005). We administered Vitamin C (1%) or vehicle in drinking water to wild-type (WT) and Sod1-/- male mice from 12 weeks of age for 8 weeks (N = 3-4 / each group). At 20 weeks of age, we made histological sections of supraspinatus enthesis and performed haematoxylin-eosin and toluidine blue staining. We analyzed the sections using a quantitative histologic evaluation (Koike et al., JOR 2005). ResultsIn vehicle drinking group, Sod1-/- mice showed a decrease in the evaluation parameters, number of chondrocytes, the percentage of aligned chondrocytes, the area of fibrocartilage and spatial arrangement collagen fibers, compared to WT mice. Furthermore, in Sod1-/- mice, vitamin C treatment significantly increased these parameters compared to vehicle group and improved to the same level as WT mice. In WT mice, no difference was observed between vitamin C and vehicle group. In vehicle drinking group, Sod1-/- mice showed a decrease in the evaluation parameters, number of chondrocytes, the percentage of aligned chondrocytes, the area of fibrocartilage and spatial arrangement collagen fibers, compared to WT mice. Furthermore, in Sod1-/- mice, vitamin C treatment significantly increased these parameters compared to vehicle group and improved to the same level as WT mice. In WT mice, no difference was observed between vitamin C and vehicle group. ConclusionSod1-/- mice showed decreases of histologic evaluation parameters and vitamin C treatment improved the reduction of these parameters. These results suggest that oxidative stress induced degeneration of supraspinatus enthesis. Sod1-/- mice showed decreases of histologic evaluation parameters and vitamin C treatment improved the reduction of these parameters. These results suggest that oxidative stress induced degeneration of supraspinatus enthesis.