Effect of all-trans-retinoic acid on tubulointerstitial macrophage infiltration in rats with renal tubulointerstitial fibrosis

Objective: To investigate the effect of at-RA in macrophage accumulation in tubulointerstitium of rats with renal tubulointerstitial fibrosis. Methods: Unilateral ureteral obstructive (UUO) rat animal models were used for the study. 40 SD rats were randomly divided into 5 grou50: sham group, UUO group, benazepril group, low-dose at-RA groups and high-dose at-RA groups. The rats were under intragastric administration by benazepril 10 mg/(kg · d) in benazepril group, and by at-RA 10 mg/(kg · d) in low-dose at-RA group and 20 mg/(kg · d) in high-dose at-RA group and by sodium chloride in tales doses in sham group and UUO group from the day before the operation to 14 day after operation. Immunohistochemistry staining of CD68 and Col III was used to define the macrophage accumulation and expression of interstitial Col III. The degree of tubulointerstitial damage was scored by HE and Masson staining. Results: Tubulointerstitial macrophage infiltration were all significantly reduced by at-RA or benazepril treatment. They also improved the histological changes of UUO rats and inhibited interstitial colIII deposition. Conclusion: Reduction of interstitial macrophage infiltration may be an important event by which at-RA or benazepril prevents renal injury caused by UUO.