A Gender Comparison of Post-obstructive Injury in the Rat Kidney

KIDNEY AND BLOOD PRESSURE RESEARCH

Karger

Lugar: Switzerland; Año: 2010 p. 266 - 273

1420-4096

Background/Aims: Unilateral obstruction (UUO) results in significant renal injury.  Studies have reported increases indices of injury in male rats following UUO. This work examined whether this gender-based renal response to UUO was reflected in sustained differences during the recovery phase following the relief of obstruction. Methods: Adult male and female rats (weight) were subjected to either sham surgery (S/RN) or UUO (UUO/RN). At 24 hours, obstruction was relieved and all animals underwent a contralateral nephrectomy. On the fifth day following initial surgery, animals were placed in metabolic cages and provided with water ad libitum for 24 hours followed by a 24 hour period of complete water restriction. Sequential 24 hour urine volumes were collected from each phase. On day 7, animals were euthanased and plasma and tissue samples harvested. Tubular injury, urinary volume and osmolality, creatinine clearance, plasma arginine vasopressin, renal medullary V2 receptor and Aquaporin 2 (AQP2) expression were compared between sexes. Results: Male UUO/RN rats showed evidence of increased renal apoptotic injury and reduced creatinine clearance (glomerular filtration rate (GFR)) rates versus females. No gender dependent differences were observed in urinary osmolality or urinary concentrating ability. AQP2 expression increased post-obstruction and was significantly increased in male rats per se. Conclusion: Increased renal injury in male rats following UUO remains manifest during the early recovery phase after release of obstruction. Despite this, the grade of post-obstructive diuresis is not significantly altered between the sexes. This may in part reflect the reduced GFR and elevated AQP2 observed in male rats.