Abstract: Objective To observe the antioxidative capability and the mRNA expression of sodium pump α1-subunit in kidney of hypothyroid rats by iodine deficiency and illuminate the pathogenesis of kidney damage. Methods Wistar rats were divided into two groups randomly, that were control group (NT) and hypothyroid group (HT). The two group rats were all fed with low-iodine diet derived from an endemic goiter area and drank deionized water containing different potassium iodide to duplicate hypothyriod animal models. We determined the morphometric parameters of kidney by routine histology method., The contents of malondialdehyde and free radical scavengers (GSH-PX and SOD) in kidney tissue were measured in two groups, as well as the activity of Na+-K+ATPase. The mRNA expression of sodium pump α1 subunit was determined by reverse transcription-polymerase chain reaction. Results Compared with that in the control group, in hypothyroid group ①serum freeT3 、free T4 、total T3 and total T4 were markedly lower . ②mean glomerular area and volum diminished markedly. ③the content of MDA and activity of PGx increased markedly, But the activity of SOD decreased significantly , as well as the one of Na+-K+-ATPase. ④the mRNA expression level of sodium pump α1 subunit was lower. Conclusion In hypothyroid state, the decrease of antioxidative capability of kidney resulted in lipid peroxidative damage, atrophy of kidney and the decreased activity of Na+-K+-ATPase, as well as degression of sodium pump α1 subunit mRNA expression.

Key words: hypothyroid, lipid peroxidative damage, Wistar rat, Kidney, morphology, Na+, K+-ATPase