[Effects of FK506 on aminonucleoside-induced nephrotic rats]

We examined the effect of immunosuppressive agent, FK506 (Fujisawa, Co.), on puromycin aminonucleoside (PAN)-induced nephrosis. Single i.p. injection of PAN in a dose of 100 mg/kg was introduced into Munich-Wistar rats weighing about 200 g. Those rats were divided into four groups. PAN-induced nephrosis rats in group 1 (PAN-FK0.1, n = 5), group 2 (PAN-FK0.3, n = 5), group 3 (PAN-FK1.0, n = 5) were treated with i.m. injection of FK506 for 10 days in a dose of 0.1 mg/kg, 0.3 mg/kg, 1.0 mg/kg, respectively, and rats in group 4 were treated with FK-placebo (PAN-PL, n = 5). The rats in group 5 with Saline+placebo were served as a control (NS-PL, n = 5). Among 5 groups, urinary protein, anionic sites (AS) in GBM, and subsets of peripheral lymphocytes through FACS were compared. After 9 days of PAN injection, the rats in PAN-FK0.1 (160.0 +/- 38.4), PAN-FK0.3 (118.0 +/- 34.4) & PAN-FK1.0 (89.2 +/- 40.0) given FK-506 had significantly less proteinuria in a PAN dose dependent manner, compared to those in NS-PL (349 +/- 86.8 mg/day). The numbers of AS/1000 mmGBM were more attenuated in FK506-treated PAN rats (PAN-FK1.0; 16.2 +/- 3.9) than those in PAN-PL (11.7 +/- 4.4). In related to subset of lymphocytes, increased W3/25 in PAN-PL was regressed in PAN-FK0.1, PAN-FK0.3 & PAN-1.0 after 10 days of PAN-injection. W3/25/OX-8 was significantly higher in PAN-PL (3.6) than those in NS-PL (2.4), but not between PAN-1.0 & NS-PL. These data indicate that the mechanism for therapeutic effect of FK506 on PAN-induced nephrosis includes a revision of abnormal cellular immunity, which attenuates the decrease of AS structure and as a result decrease proteinuria.