Dexamethasone causes defective glucose-6-phosphate dehydrogenase dependent antioxidant barrier through endoglin in pregnant and nonpregnant rats

Abstract

Glucocorticoid therapy has been associated with adverse cardiometabolic effects during pregnancy. Inflammation-mediated cardiac dysfunction, an independent risk factor for morbidity and mortality, has been linked to defective glucose-6-phosphate dehydrogenase (G6PD) dependent antioxidant defenses and increased endoglin expression. We therefore sought to investigate the effects of dexamethasone (DEX) on cardiac endoglin and G6PD-dependent antioxidant defense. Twenty-four rats were randomly assigned to nonpregnant (PRE(–)), DEX-exposed nonpregnant (PRE(–) + DEX), pregnant (PRE(+)), and DEX-exposed pregnant (PRE(+) + DEX) rats, respectively (n = 6 per group). PRE(–) and PRE(+) rats received vehicle (per oral (po)), while PRE(–) + DEX and PRE(+) + DEX groups were administered DEX (0.2 mg/kg po) between gestational days 14 and 19, respectively. Results showed that DEX caused increased cardiac pro-inflammatory markers (adenosine deaminase (ADA) activity, endoglin, vascular cell adhesion molecule-1 (VCAM-1), tissue injury markers (LDH, GGT, AST, ALT, and ALP), metabolic disturbances (elevated fasting plasma glucose, free fatty acid (FFA), lactate, cardiac FFA, and lactate) and depressed G6PD-dependent antioxidant defenses (G6PD activity, reduced glutathione/oxidized glutathione ratio, and nitric oxide) in pregnant and nonpregnant rats. The present study demonstrates that DEX led to increased cardiac endoglin and VCAM-1 that is accompanied by defective G6PD-dependent antioxidant defenses but not cardiac lipid accumulation in both pregnant and nonpregnant rats.