Renal interstitial leukocyte infiltration is diminished by at-RA treatment. A) Interstitial cell infiltration evaluated by light microscopy in periodic acid-Shiff (PAS)-stained renal tissue. Representative images from HgCl2-injected rats (a) and HgCl2-injected rats and also treated with at-RA 15 mg/Kg (b) are shown. B) Renal interstitial mononuclear cell infiltrates characterization. Immunoperoxidase staining for CD3+ and CD68+ cells in renal tissue at day 13 of the disease, from HgCl2-injected rats (a-b), from HgCl2-injected rats also treated with at-RA (c-d), from rats treated only with at-RA (e-f) and vehicle (g-h).