Hypothyroidism modifies the expression of genes related to oxidative stress in rat heart.

CARMONA Y, VAZQUEZ M, CORIA M, OLIVEROS L, GIMENEZ MS.

Tucumán, Argentina

Congreso; SAIB 2009; 2009

SAIB

Different studies on the effects of thyroid status on oxidative stress in heart have produced conflicting results. In this work the effects of hypothyroidism on gene expressions of antioxidant enzymes and Nrf-2, a redox-sensitive transcription factor, were determined in heart ventricles of female virgin  Wistar rats. Also, the activities  of  catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), and the TBARs and Carbonil groups levels in heart were measured. The hypothyroid state was induced in rats weighing 150-180 g by administration of 6-n-propyl 2-thiouracil (100 mg/L) in the drinking water for 30 days. Age-matched euthyroid rats were used as controls. The mRNA expressions  were determined by RT-PCR, using  â-actin as internal control, and the enzyme activities by spectrophotometric assays. Heart mRNA levels of  NADPH oxidase-2  (NOX-2) and its modulate factor NRF-2 increased(P< 0.002 and P<0.03 , respectively). The mRNA expressions of SOD increased (P<0.005),CAT decreased (P<0.02) and GPx was unchanged, compared with their respective controls. The activity of GPx increased (P< 0.04), while that of CAT and SOD was unchanged in relation to control. No difference in TBARs and Carbonil levels was observed. The results suggest that hypothyroidism induces a prooxidant state at the gene levels in heart ventricles.