The role of vitamin A in preventing renal scarring secondary to pyelonephritis.

Abstract

To evaluate the efficiency of exogenously administered vitamin A in preventing renal scarring caused by experimental pyelonephritis in rats. Forty Wistar rats were injected with 0.1 mL of solution containing Escherichia coli (1010 /mL) into both renal medullae. Five equal groups were then formed: group 1 was treated only with ciprofloxacin (30 mg/kg per day, twice daily, intraperitoneally) for 5 days, starting 3 days after bacterial inoculation; in group 2, 60 kIU of vitamin A was injected intramuscularly with the bacterial inoculation; in group 3, 60 kIU of vitamin A was injected similarly, but 3 days after bacterial inoculation; in group 4, 60 kIU of vitamin A was given orally with the bacterial inoculation; and group 5 was treated with ciprofloxacin for 5 days and vitamin A intramuscularly from the third day after bacterial inoculation. All the rats were killed 6 weeks after bacterial injection; blood samples were obtained to determine serum vitamin A and beta-carotene levels, and both kidneys were examined pathologically for scarring, graded as 0 (none), 1 (mild), 2 (moderate) and 3 (severe). Serum vitamin A levels were higher in the rats given vitamin A (group 2-5) than in group 1, being highest in group 4, although only this group had significantly higher levels of vitamin A than group 1 (P<0.05). Histopathologically, the fibrosis was mildest in groups 2 and 4 (two of 16 kidneys grade 1), whereas it was most severe in group 1 (all 16 grade 2-3). Fibrosis was significantly less in groups 2-5 than in group 1 (P<0.05). There was a significant negative correlation between vitamin A levels and the sum of the fibrosis, inflammation and tubular atrophy scores of all rats (r=-0.391, P<0.02). beta-carotene levels were unrelated to renal scarring. The administration of vitamin A could have a role in preventing renal scar formation from pyelonephritis induced experimentally in rats.