Effect of Vitamin C Supplements on Antioxidant Defence and Stress Proteins in Human Lymphocytes and Skeletal Muscle

Abstract

Oxidative stress induces adaptations in the expression of protective enzymes and heat shock proteins (HSPs) in a variety of tissues. We have examined the possibility that supplementation of subjects with the nutritional antioxidant, vitamin C, influences the ability of lymphocytes to express protective enzymes and HSPs following exposure to an exogenous oxidant and the response of skeletal muscle to the physiological oxidative stress that occurs during exercise in vivo. Our hypothesis was that an elevation of tissue vitamin C content would reduce oxidant‐induced expression of protective enzymes and HSP content. Lymphocytes from non‐supplemented subjects responded to hydrogen peroxide with increased activity of superoxide dismutase (SOD) and catalase, and HSP60 and HSP70 content over 48 h. Vitamin C supplementation at a dose of 500 mg day−1 for 8 weeks was found to increase the serum vitamin C concentration by ∼50 %. Lymphocytes from vitamin C‐supplemented subjects had increased baseline SOD and catalase activities and an elevated HSP60 content. The SOD and catalase activities and the HSP60 and HSP70 content of lymphocytes from supplemented subjects did not increase significantly in response to hydrogen peroxide. In non‐supplemented subjects, a single period of cycle ergometry was found to significantly increase the HSP70 content of the vastus lateralis. Following vitamin C supplementation, the HSP70 content of the muscle was increased at baseline with no further increase following exercise. We conclude that, in vitamin C‐supplemented subjects, adaptive responses to oxidants are attenuated, but that this may reflect an increased baseline expression of potential protective systems against oxidative stress (SOD, catalase and HSPs).

Vitamin C supplementation influences the antioxidant response and nitric oxide handling of erythrocytes and lymphocytes to diving apnea

“…Our modest changes in antioxidant system agrees with the results obtained in previous studies after static and dynamic apnoeas (Joulia et al, 2002;Joulia et al, 2003). Increased ROS production can activate the CAT in erythrocytes (Tauler et al, 1999) and induce the synthesis of antioxidant enzymes such as SOD in lymphocytes (Khassaf et al, 2003;Tauler et al, 2003). We previously reported that exhaustive exercise induced a general increase in the lymphocyte antioxidant enzyme activities, which could be influenced by vitamin C supplementation (Tauler et al, 2003).…”

Superoxide dismutase and catalase anti-oxidant activity in leucocyte lysates from hypertensive patients: effects of eprosartan treatment

“…29 the oxidative stress in leucocytes induced by hypertension could provoke, as observed in our results, an increase and not a decrease in SOD and CAT activities. Treatment with eprosartan leads to a reduction in these activities, parallel to the normalisation of blood pressure values.…”

Reactive oxygen species and redox-regulation of skeletal muscle adaptations to exercise

“…A single period of contractile activity in mouse muscle was found to increase muscle SOD and catalase activity together with HSP60 and HSP70 content , changes which were replicated in human muscle (Khassaf et al 2001). Pre-supplementation with vitamin C reduced these responses, supporting the possibility that they are regulated by ROS (Khassaf et al 2003). The possibility that ROS can directly modulate stress responses to contraction in skeletal muscle has been examined by using Clontech cDNA expression arrays to determine whether hydrogen peroxide treatment could induce changes in stress gene expression in skeletal muscle in culture and comparison of these changes with those seen in skeletal muscle in vivo at the same time points following a period of non-damaging contractile activity known to induce a substantial generation of oxidants .…”