Changes in lymphocyte oxidant/antioxidant parameters after carbonyl and antioxidant exposure.

During normal B- and T-cell life, processes including activation, proliferation, signaling pathways and apoptosis are markedly dependent on ROS generation. However, these cells can also suffer the effect of oxidant overproduction. Thus, the purpose of the present study was to examine the possible pro-oxidant effects of MGO/high glucose and antioxidant effects of astaxanthin associated with vitamin C on some oxidative and antioxidant parameters of human lymphocytes in vitro. Lymphocytes from healthy subjects were treated with 20mM of glucose and 30 μM MGO followed or not by the addition of the antioxidants astaxanthin (2 μM) and vitamin C (100 μM) for up to 24h. We examined superoxide dismutase (SOD), catalase, glutathione peroxidase, glutathione reductase, and glucose-6-phosphate dehydrogenase (G6PDH) activities, GSH/GSSG ratio and total thiol and carbonyl content. Oxidative parameters included superoxide anion, hydrogen peroxide and nitric oxide production. The association of astaxanthin and vitamin C proved to be a powerful antioxidant in human lymphocytes as showed by the marked reduction in superoxide anion, and hydrogen peroxide production as well as increased GSH content, GSH/GSSG ratio, GPx and GR activities. The antioxidant association showed to be more potent than their individual application. High glucose and methylglyoxal did not promote oxidative stress in human lymphocytes, since neither the oxidative parameters nor the antioxidant defense system was altered. According to these results, new therapies with the association of astaxanthin and vitamin C may be helpful to improve the immune function of patients with exacerbated production of ROS.