ABSTRACT
To evaluate the effect of betamethasone in preventing renal scarring in rat model of pyelonephritis. Material and Sixty three female Sprague-Dawley rats were divided into seven equal groups [A-G]. After exposing the left kidney under general anesthesia, direct inoculation of colonies of mannose-sensitive E.coli was done in groups C-G and normal saline in group B. No injection was done in group A. After 48 hours of bacterial inoculation, intramuscular [IM] injections of gentamicin [3 mg/kg/ day for 10 days] was used in groups C, E and F. Betamethasone [0.3 mg/kg/day IM] was used after two days [group D and E] and 5 days [group F] of bacterial inoculation. Normal saline as daily IM injections for 10 days in group B and no IM injection in group G was done. After 8 weeks of bacterial inoculation, the rats were sacrificed and the volume of renal scar was determined using a point- counting technique. Changes in the weight and volume of the kidneys were not statistically significant. No scar was detected in group A, but all the other groups with intrarenal injections [including group B with no bacterial inoculation] had scarring. The volume density and absolute volume of the scar in groups C-G were significantly more than group B [p < 0.001], but no statistically significant difference was observed in groups C-G. Betamethasone with or without gentamicin, when used 48 hours or more after induced pyelonephiritis is not effective to prevent renal scar