Pharmacokinetic profile of BL5923 and recruitment of monocytes into the renal interstitium of db/db mice. A: BL5923 was applied once orally at 60 mg/kg to groups of six 2K db/db mice (closed circles) or 1K db/db mice (open squares). Blood samples were obtained at 30 minutes and 1 hour, 2 hours, 6 hours, and 24 hours, and the plasma level of BL5923 were determined by HLPC/MS and expressed as mean ± SEM in μg/ml. B: 1K db/db mice 6 months of age were injected intravenously with PKH26-labeled F4/80 monocytes isolated from spleens of donor db/db mice. Recipient mice were pretreated with a single dose of either vehicle or BL5923 before injection of the respective cells, and kidneys were obtained 3 hours after injection of cells and examined by fluorescence microscopy. Fluorescence-labeled cells locate to the renal interstitium. C: Cell counts for interstitial labeled F4/80 monocytes were determined by fluorescence microscopy from 15 high-powered fields. Values are means ± SEM. *P < 0.001. Original magnifications, ×400.