Aquaporin-2 expression in the kidney and urine is elevated in rats with monocrotaline-induced pulmonary heart disease

OBJECTIVE: Little is known about how renal aquaporin-2 (AQP2) expression is affected by right heart failure caused by pulmonary heart disease (PHD). Therefore, we examined the expression of AQP2 in a rat model of PHD induced by monocrotaline (MCT). METHODS: After 4 weeks of treatment, urine and blood samples were collected from sham-treated and MCT-treated rats. Plasma arginine vasopressin (AVP) levels were measured by radioimmunoassay, and kidney Aqp2 mRNA expression was detected by reverse transcription (RT)-PCR. Kidney AQP2 protein expression was quantified by immunohistochemistry and western blotting assays. The concentration of urine AQP2 was determined by indirect enzyme-linked immunosorbent assay. RESULTS: We successfully established an animal model of MCT-induced PHD in rats. MCT-treated rats had significantly higher mRNA and protein levels of AQP2 in their kidney tissue. Following MCT treatment, rats also had markedly increased concentrations of both urine AQP2 and plasma AVP. CONCLUSIONS: AQP2 expression was significantly increased in the kidney tissues and urine of rats with PHD induced by MCT. Our findings suggest that the evaluation of AQP2 expression contributes to an early diagnosis of PHD, and may also be an important reference to improve PHD therapeutics.