Cisplatin treatment reduces contraction to angiotensin II by altering expression of angiotensin II receptors: a pilot study

Abstract

The renin angiotensin system is a key regulator of blood pressure homeostasis. Angiotensin type 1 (AT₁R) and 2 receptors (AT₂R) have been investigated as targets for cisplatin-induced acute kidney injury; however, their therapeutic potential remains inconclusive. This pilot study aimed to determined the effect that acute cisplatin treatment had on angiotensin II (AngII)-induced contraction in blood vessels and expression profiles of AT₁R and AT₂R in mouse arteries and kidneys. Male C57BL/6 mice at 18 week of age (n = 8) were treated with vehicle or bolus dose of cisplatin (12.5 mg/kg). Thoracic aorta (TA), adnominal aorta (AA), brachiocephalic arteries (BC), iliac arteries (IL) and kidneys were collected for isometric tension and immunohistochemistry analysis. Cisplatin treatment reduced IL contraction to AngII at all doses (p < 0.01, p < 0.001, p < 0.0001); however, AngII did not induce contraction in TA, AA or BC in either treatment group. Following cisplatin treatment, AT₁R expression was significantly upregulated in the media of TA (p < 0.0001) and AA (p < 0.0001), and in the endothelium (p < 0.05) media (p < 0.0001) and adventitia (p < 0.01) of IL. Cisplatin treatment significantly reduced AT₂R expression in the endothelium (p < 0.05) and media (p < 0.05) of TA. In renal tubules, both AT₁R (p < 0.01) and AT₂R (p < 0.05) were increased following cisplatin treatment. Herein, we report that cisplatin reduces AngII-mediated contraction in IL and may be explained by an absence of normal counterregulatory expression of AT₁R and AT₂R, indicating other factors are involved.

Keywords: Angiotensin II; Angiotensin type 1 receptor; Angiotensin type 2 receptor; Cisplatin; Contraction; Renin angiotensin system.