P0090SPIRONOLACTONE ALLEVIATES ISCHEMIC STROKE SEVERITY IN MALE MICE WITH CHRONIC KIDNEY DISEASE

Abstract

Abstract Background and Aims Ischemic stroke is highly prevalent in patients with chronic kidney disease (CKD) and has been associated with poor outcomes. In experimental studies, CKD mice display wider and more inflammatory ischemic lesions as well as poorer functional outcomes than mice with normal renal function. In rodents with normal renal function, treatment with a mineralocorticoid receptor antagonist decreases brain ischemic lesion and improves functional outcomes. The goal of this study was to investigate the impact of a treatment with spironolactone, a mineralocorticoid receptor antagonist, on stroke outcomes in CKD mice. Method Male C57BL/6J mice were randomly assigned to CKD or SHAM groups. CKD was induced through right kidney cortical electrocautery in 8 week-old mice followed 2 weeks later by left total nephrectomy. Mice received spironolactone (50 µg/kg/day) or placebo (subcutaneous tablets, Innovative Research of America) for 6 weeks until stroke induction by transient middle cerebral artery occlusion (tMCAO). Neurological deficits were monitored daily, 3 days before and 1 day after stroke induction. Mice were euthanized 24 hours after tMCAO. Total infarct volumes and apoptosis were determined by cresyl violet staining and TUNEL respectively. Immunohistochemical detection of neurons was performed using an anti-NeuN antibody. To characterize the pro-inflammatory polarization of microglia/macrophages, M1 signature genes’ expression (CD-32, IL-1β and IL-6) was analyzed by qPCR. Results Untreated CKD mice displayed wider ischemic lesions (40.3 ± 4.5 versus 23.8 ± 3.9 mm3; p < 0.05) and poorer neurological score, grip strength and prehensile abilities compared to untreated sham mice. Pro-inflammatory M1 signature genes’ expression (CD-32, IL-1β and IL-6) was significantly increased in the ischemic hemisphere of CKD mice compared to the non-ischemic hemisphere. Treatment with spironolactone decreased ischemic lesion (19.3 ± 5.1 mm3; p < 0.05) and improved neurological score, grip strength and prehensile abilities in CKD mice. Treatment with spironolactone also reduced apoptosis, neuronal loss and microglia/macrophages pro-inflammatory M1 signature genes’ expression in CKD mice. In contrast, treatment with spironolactone had no effect in sham mice. Conclusion These data demonstrate that the mineralocorticoid receptor could be a promising therapeutic target to decrease brain inflammation and improve stroke recovery in CKD.