Ibuprofen combined with antibiotics suppresses renal scarring due to ascending pyelonephritis in rats

Purpose: In acute pyelonephritis renal scarring may be decreased by immedia te antibiotic therapy. Unfortunately in children there is often a delay in starting treatment, which increases the likelihood of renal scarring. In ro dents immediate antibiotic therapy is effective for preventing renal scar f ormation resulting from experimentally induced pyelonephritis. However, the same treatment beginning 72 hours after infection does not prevent renal s carring in this paradigm. We examined whether delayed administration of the nonsteroidal anti-inflammatory agent ibuprofen only or combine with antibi otics suppresses renal scarring in a model of ascending pyelonephritis in r ats. Materials and Methods: An inoculum of 5 x 10(9) organisms per ml. of Escher ichia coli strain BH-5 was instilled into the bladder of rats and the ureth ra was occluded for 4 hours. Groups of animals were and were not treated wi th 15 mg./kg. cefadroxil or 10 mg./kg. ibuprofen given twice daily for 5 da ys, or the 2 drugs combined. Treatment began 72 hours after inoculation. In an additional group of rats sterile phosphate buffered saline was instille d into the bladder. In each rat the kidneys were examined grossly and micro scopically 6 weeks later. Results: Combined antibiotics and ibuprofen significantly inhibited gross r enal scarring compared with no treatment or antibiotics only (p <0.05). No difference in renal scarring was detected in animals that received no treat ment versus those that received antibiotics or ibuprofen only (p >0.05). Conclusions: Renal scarring resulting from acute pyelonephritis in this rat model is not decreased by delayed treatment with antibiotics only. The add ition of ibuprofen to antibiotic therapy is effective for decreasing renal scarring due to acute pyelonephritis even when treatment is delayed for 72 hours.