OSTEOCLAST PIT VOLUMES STANDARDIZED BY ATOMIC-FORCE MICROSCOPY ARE DECREASED BY ETHOXZOLAMIDE

Quantitation of in vitro bone resorption by osteoclasts is difficult a nd time-consuming. For these experiments, we have used manual stereoph otogrammetry to analyze resorption pit volumes after inhibition of aci d production by ethoxzolamide, a carbonic anhydrase inhibitor.:In addi tion, we standardized depth measurements found by stereoscopic analysi s of scanning electron micrographs of osteoclast pits with atomic forc e microscopy. These corrected measurements served to calculate pit vol umes produced by osteoclasts treated with ethoxzolamide which inhibits bone resorption, by interfering with the production of acid in the re sorption cavity. Significant differences in pit depths were found in t hese studies. Inhibition of acid production also decreased pit volumes significantly (p < 0.01 by Mann-Whitney) from a median of 750 mu m(3) to 97 mu m(3). Planar areas of osteoclast resorption were not predict ive of depth changes between experimental groups. Analysis of pit volu mes also:allowed comparison between calculated values of osteoclast wo rk on different surfaces.