Hydraulic conductivity of basement membrane with computed values for fiber radius and void volume ratio.

The basement membrane contributes to resistance to ultrafiltration of the capillary wall, but efforts to conduct studies of this material have been hindered by difficulty in obtaining homogenous sources and by compression from high filtration pressures. We utilized Matrigel in a conductivity chamber and showed that it reproducibly yielded a specific hydraulic conductivity of (2.247 +/- 0.328) x 10(-14) cm2, which is within 21% of that obtained for porcine glomerular basement membrane by Robinson and Walton (Microvasc. Res. 38: 36-48, 1989). No compression or hysteresis was observed over 5-25 cmH2O pressure difference. Depending on whether data were fit to drag or hydraulic radius fibermatrix models, fiber radius was 0.626-0.696 nm, and void volume ratio varied between 0.826 and 0.846, the former agreeing with the major components of Matrigel. Ready availability of Matrigel, its uniform hydraulic conductivity, and its fit to fibermatrix theory make it ideal to study changes in basement membrane during physiological and pathological changes. Moreover, results of such studies are likely applicable to endothelial barriers, whose luminal and intercellular surfaces are lined with fibrillar materials.