Regulation of oxidative stress and lipid peroxidation in PTU induced mice, treated with Pyrroloquinoline quinone (PQQ)

Hitherto unknown effects of Pyrroloquinoline quinone (PQQ) in 6-n-propyl-2-thiouracil (PTU)induced oxidative stress and lipid peroxidation were investigated in adult mice. Animals received either PTU (0.05% in drinking water) alone for 5 weeks or PTU + three different concentrations of PQQ, after which alterations in tissue lipid peroxidation (LPO) and in enzymatic activities of superoxide dismutase (SOD) and catalase (CAT) and in glutathione (GSH) content were evaluated in two different organs such as liver and heart. Simultaneously, concentrations of serum glucose, total cholesterol, glutamate oxaloacetate transaminase (SGOT), glutamate pyruvate transaminase (SGPT), creatinine and urea were measured in serum. PTU administration enhanced the tissue LPO, serum SGOT, SGPT, total cholesterol, creatinine and urea with a parallel decrease in serum glucose and tissue antioxidants such as SOD and CAT in both the organs. When PTU treated animals received PQQ, these adverse effects were ameliorated. Out of three different doses of PQQ (1, 5 and 10 mg/kg/d, i.p. for 6 days), 10 mg/kg body weight was found to be the most effective and antiperoxidative in nature, as it maximally reduced the LPO of liver and heart, with a parallel increase in cellular antioxidants. Findings from this study revealed for the first time, that PQQ has the potential to ameliorate PTU-induced oxidative damage in liver and heart, indicating the possible beneficial effect of the test compound in regulating hypothyroidism.