GLUCOSE-6-PHOSPHATE-DEHYDROGENASE AND GLUTATHIONE-REDUCTASE SUPPORT ANTIOXIDANT ENZYMES IN NERVES AND MUSCLES OF RATS DURING NERVE REGENERATION

The effects of the rat sciatic nerve crush on the activities of glucos e-6-phosphate dehydrogenase (G6PD), glutathione reductase (GR), glutat hione peroxidase (GPX), superoxide dismutase (SOD) and catalase (CAT) were examined in regenerating nerve and in two reinnervating muscles: the slow twitch soleus and the fast twitch extensor digitorum longus ( edl). The enzyme activities in the crushed side, were compared with th e contralateral homologue tissues and basal values, determined in uncr ushed animals. In the crushed side, the activity of G6PD, GR, GPX and CAT of the sciatic nerve and both muscles markedly increased in compar ison with the uncrushed side. In the nerve and in both muscles, SOD ac tivity decreased at 13 days, then rose to values higher than normal, b ut the pattern of the crushed side was not significantly different fro m that of the uncrushed. In the uncrushed side, we observed a signific ant increase of nerve G6PD, GPX and CAT activities compared to basal v alues, while in both muscles, values fluctuated around the normal with out any significant variation. The mechanism of these enzymatic change s is unknown, however our work suggests that: (i) during nerve regener ation, an oxidative stress occurs in nerve and muscle, which causes ad aptive responses in antioxidant enzymes; (ii) the maximum antioxidant power is expressed during the period of synaptic retraction; (iii) G6P D and GR activities are synergistically modulated with GPX and CAT, wh ile SOD activity appears independently regulated.