Glomerular size and charge selectivity in the mouse after exposure to glucosaminoglycan-degrading enzymes

This is the first functional study of glomerular size and charge selectivity in mice. The aim was to investigate the controversial issue of glomerular permselectivity in animals exposed to glucosaminoglycan-degrading enzymes, hyaluronidase, and heparinase. Fractional clearances (theta) for FITC-Ficoll and albumin were estimated in isoflurane anesthetized mice in vivo and in cooled isolated perfused kidneys (cIPK). In cIPK, a significant increase of theta(albumin) from 0.0023 (95% confidence interval, 0.0014 to 0.0033) in controls to 0.0130 (95% confidence interval, 0.0055 to 0.0206) was seen after hyaluronidase treatment. The theta for neutral Ficoll of similar size as albumin was 0.063 to 0.093 in all groups. According to a heterogeneous charged fiber model, the fiber volume fraction of negatively charged fibers decreased by 10% after enzyme treatments. It is concluded that glomerular size and charge selectivity in mice is similar to that previously shown for rats. Moreover, hyaluronic acid, chondroitin sulfate, and heparan sulfate are of importance for charge selectivity.