Age and Gender-Related Changes in Renal Haemodynamics of Albino Rats: The Possible Role of Cytokines and Prostaglandins

Abstract
Background: The normal aging process leads to changes in kidney morphology, hemodynamics and function, which are influenced by several factors, including gender. Females develop less age-dependent loss of renal function due to cardiorenal protective effects of estrogens.
Aim of Study: The aim of this study was to elucidate the age and gender-related changes in some renal haemodynamics in albino rats with special focusing on the role of cytokines and prostaglandins in establishment of such changes.
Material and Methods: Sixty albino rats (30 males & 30 females) of local strain were divided into 2 major groups (Group I of male rats and Group II of female rats) was further subdivided into 3 subgroups: Young (4wk), young adult (3mo) and old (25mo). Body Weight (BW) and absolute Kidney Weight (KW) were measured. The Systolic Blood Pressure (SBP) of the rats was measured by the rat-tail plethysmography technique using a tail-cuff sphygmomanometer. The Renal Blood Flow Velocity (RBFV) and Renal Vascular Resistance (RVR) were measured using bi-directional blood flow meter with FFT-analysis. The blood samples were collected after a period of overnight fasting, left to be clotted, centrifuged and serum was separated for measurement of serum testosterone in male rats, serum estrogen in female rats, creatinine clearance, serum IL1beta, IL6 and serum PGE.
Results: The aging of male rat group is accompanied by change in the renal hemodynamic and some blood measure-ments. This is represented by significant increase in systolic blood pressure, renal vascular resistance, serum PGE, serum interleukin1-b & 6, impaired renal function and significant decrease of renal blood flow. It was observed that the old female group had decreased in estrogen hormone level, which led to increase in systolic blood pressure, renal vascular resistance, serum PGE, serum interleukin1-b & 6 and signif-icant decrease renal blood flow.
Conclusion: Aging has a significant influence in renal hemodynamic (decrease of renal blood flow and increase of renal vascular resistance) and also, serum interleukin1-b & 6 have a role in this change accompanied with pathophysiology of aging. Female is more protected from complications of the kidney aging than male due to the previous effect of estrogen hormone.