A dose-response study has been undertaken to clarify our proposed mechanistic axiom relating manifest UV-induced nephrotoxicity to protective effects of gradated T supplementation. Study was for 20days (d) at exposure rate of 50min/d for 5d in 50 acclimatized pre-pubertal, unsexed rabbits (PR) randomly assigned to 5 groups of 10PR each, fed concentrate feed and forage (Tridax procumbens) – basal diet (BD) and BD supplemented with 0% (Control), 2%, 4%, 6% and 12% pulverized crude T respectively. Feed and water were available ad libitum. Blood was collected by marginal venopuncture on 21d from 0900h for assessment of renal nephrotoxicity indexed as changes in plasma/serum concentrations of urea and creatinine (CR) determined by standard titrimetric/colorimetric methods. Data were analyzed by ANOVA. Dose dependent increases in secretion of both indices were observed. Highest amount of secreted urea occurred in rabbits fed 2% T followed by 4% T and were significantly (p<0.05) higher than control and 6% T rabbits. At 12% T amount of measured urea dropped very significantly (p<0.05) below control value with a reversal to negative value. Similar increasing trend occurred in CR secretion, exhibiting initial non-significant (p>0.05) splay at 2% T followed by continuous significant increases (p<0.05). Unlike urea, highest CR secretion occurred at 6% T and without a reversal to negative value. These results strongly demonstrated potent dose dependent nephroprotection by gradated T supplementation.
PDF