Rat model of anti-GBM nephritis

Rabbit anti-rat GBM serum [nephrotoxic serum (NTS)] was prepared as described previously [43, 44]. The rat model of anti-GBM nephritis was induced in male Wistar–Kyoto rats that were 5 weeks old and weighed approximately 100 g (Charles River Breeding, Yokohama, Japan) with an intravenous injection of NTS (0.3 mL/100 g body weight). Open kidney biopsies (wedge biopsy) were performed with removal of about 1/10th of the kidney at 1 and 2 weeks, and kidneys were harvested at week 4 when the rats were killed. A rat kidney contains about 50 000 glomeruli. We therefore obtained >30 glomeruli for each section of the biopsy, which is adequate for data analysis. Urine collection was performed every other day for 1 week, followed by urine collection on the first and fourth days of each week for a total 4 weeks. Urinary protein:creatinine ratio and podocyte [podocin and glomerular epithelial protein 1 (GLEPP1)] and TGF-β1 mRNA excretion were measured.