The effect of vitamin A on the course of renal ablation nephropathy

Renal scarring due to pyelonephritis was shown to improve in rats given vit amin A. We evaluated the effect of vitamin A in a renal ablation nephropath y model. Four groups, each including 7 rats with 5/6 nephrectomy, were form ed: group I(no vitamin A), group II (60 kIU vitamin A), group III(120 kIU v itamin A), and group IV (180 kIU vitamin A). Four sham-operated rats compri sed the control group. After 6 weeks of 5/6 nephrectomy, the rats were sacr ificed and serum creatinine, vitamin A, and beta -carotene levels were dete rmined in addition to histopathological evaluation of the remnant kidneys. The tubulointerstitial and glomerular changes were graded as "0-3" and "0-5 " respectively, in accordance with the severity of the lesions. Tubulointer stitial score (TIS), mean glomerulosclerosis score (MGS, arithmetical mean of the sclerosis scores of 100 glomeruli), and severity of glomeruloscleros is index (SGI, ratio of the number of glomeruli with grade greater than or equal to3 sclerosis to the total number of glomeruli examined) were calcula ted for each rat. Serum creatinine levels were higher in the study groups t han the control rats (P <0.05), but there was no significant difference bet ween the study groups (although the levels increased as the dose of vitamin A increased). Serum vitamin A levels were significantly higher in the grou ps given vitamin A than the control rats and group I(P <0.05). In addition, serum vitamin A levels increased significantly in parallel to increasing d oses of vitamin A (P <0.05). Serum beta -carotene levels did not differ bet ween the groups, except for group II, which had lower levels than controls (P=0.01). MGS and SGI were significantly higher in the study groups than co ntrol rats (P <0.05), but did not differ between the study groups. Study an d control rats were not different with respect to TIS, but there was a diff erence between the control group and group III (P=0.04). Group II had the l owest MGS, SGI, and TIS scores among the study groups. When all the rats we re considered together, vitamin A levels did not correlate with the MGS and SGI, but correlated positively with the TIS (r=0.391, P=0.027). beta -caro tene levels also did not correlate with the MGS, SGI, and TIS. In conclusio n, vitamin A administration did not significantly affect the clinical and p athological course of renal ablation nephropathy in rats. Furthermore, high er doses of vitamin A might even damage renal tissue.