The GBM lining the outer aspect of the capillary loops is smooth and thin in rats administered control sheep serum at 1 month (A, 400× and 1000× magnification) and 6 months (C, 400× and 1000× magnification). The GBM lining the outer aspect of the capillary loops is thicker (B, 400× and 1000× magnification, arrow heads) and some podocytes have abnormal shape (B, thin arrow) in rats administered sheep-anti Fx1a (PHN) at 1 month. Following six months of PHN and ongoing proteinuria, some glomeruli have become sclerotic (D, 400× and 1000× magnification).