L-T4 and LA intervention prevents oxidative stress and cognitive deficit in experi-mental hypothyroid rats / 军事医学

ABSTRACT

Objective To assess the effect of levothyroxine , lipoic acid and their combination therapy on improving the cognitive deficit and on the level of oxidative stress in the serum and hippocampus tissue of adult hypothyroid rast .Methods Fifty male SD rats were randomly divided into five groupsnormal group , hypothyroidism group [ propylthioaracil ( PTU ) group], the levothyroxine sodium (L-T4) treatment group (PTU +L-T4 group), the lipoid acid(LA) treatment group (PTU+LA group), and the two-drug combination group (PTU+LT-4+LA group).After 8 weeks of treatment, the learn-ing and memory abilities of the rats were evaluated by Morris Water Maze ( MWM ) .The content of malondialdehyde ( MDA) and the activities of superoxide dismutase ( SOD) in the serum and hippocampus were respectively measured using thiobarbituric acid ,and xanthine-xanthine oxidase methods .Results Compared with the normal group , the escape latency was longer(P<0.01), the MDA level was increased and the SOD activity was decreased in the serum and hippocampus in the PTU group (P<0.001).Compared with PTU group, the SOD activity was increased and the MDA level was decreased in the PTU +L-T4 group, PTU +LA group and PTU +L-T4 +LA group(P<0.05).There was significant difference in MWM test score .Conclusion The L-T4 and LA combination therapy can significantly improve the cognitive function of hypothyroid rats.