Differential patterns of antioxidant enzyme mRNA expression in guinea pig lung and liver during development

Abstract

cDNA clones for guinea pig antioxidant enzymes, copper-zinc (CuZn) and manganese (Mn-) superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) were isolated by reverse transcription (RT)-polymerase chain reaction (PCR) cloning, to explore the mechanisms regulating the differential expression of antioxidant enzymes (AOEs) in guinea pig lung and liver, during development. Increases in MnSOD, CAT and GPx mRNA expression in lung and, MnSOD mRNA in liver, were seen during the final period of gestation, whereas CuZnSOD and CAT mRNA expression in liver, which was constant during gestation, increased in the postnatal period. In lung, CuZnSOD mRNA level decreased just prior to birth while in liver, GPx mRNA expression declined markedly over the last third of gestation. In lung, while the mRNA levels of MnSOD, CAT, and GPx increased pre-natally, they declined following birth. In contrast, the postnatal increase in mRNA for CuZnSOD and CAT and the prenatal increase in MnSOD mRNA expression in liver remained at least to adolescence. In adolescent guinea pigs, CuZnSOD and CAT mRNA were most abundantly expressed in liver, while MnSOD and GPx mRNA were most abundant in heart and spleen, respectively. These results demonstrate markedly different developmental patterns of AOEs expression in guinea pig lung and liver during both the pre- and post-natal period. The short-lasting, late-gestational increases of MnSOD, CAT, and GPx mRNA expression in lung, may be responsible for the temporary increases in the activity of these antioxidants in the late gestational period, whereas the steady increases of CuZnSOD, CAT mRNA following birth, and also the prenatal increases in MnSOD mRNA expression, are probably responsible for the higher postnatal activity of these antioxidants in liver.