Sex Differences in Kidney Damage in BUF/MnaMcwi Rats

Abstract

Kidney disease is commonly found in the BUF (Buffalo) strain of rats. It has been observed that male BUF rats show signs of focal glomerulosclerosis (FSGS). They are known to have proteinuria, hypoalbuminemia, and hyperlipidemia as they age. This is preceded by renal macrophage activation and Th2 lymphocyte polarization. There is no prior literature that explores kidney disease in female BUF rats.We previously observed that kidneys in female BUF rats appeared more damaged than their male mates, leading to the hypothesize that the female BUF/MnaMcwi (BUF) breeder rats have greater kidney damage features than male mates. To determine the relationship between sex and function, we collected urine samples using metabolic cages (at 12, 17, and 23 weeks of age), harvested organ tissue (heart left, ventricle, spleen, thymus, and kidneys), and used histopathological examination of formalin-fixed paraffn-embedded kidney samples to determine cortex tubule damage and glomerular area. We expected to see sex differences in relative sizes (mg/g BW) of the thymus, heart left ventricle, kidneys, and spleen. We found that the male BUF rats had larger absolute body weight (g), as expected. We also found that there were no significant sex differences in relative sizes (mg/g BW) of the thymus, heart left ventricle, and spleen. There was a significant sex difference in relative total kidney size (mg/g BW), with the females having larger kidney sizes compared to their body weight. In addition, there was increased microalbumin in the female BUF overnight urine collection that was significantly higher than the male BUF rats. There was no significant sex difference in the microalbumin: creatinine ratio. Finally, we found no significant sex difference in cortex tubular damage between the age-matched BUF rats, but there was a significant difference in glomeruler area (mm 2), with male glomeruler areas being significantly larger. Future studies will be done to replicate the findings and determine if virgin females show the same results. ASPIRE Program (R25HL 168782) Medical College of Wisconsin. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.