Effects of pressure on bone resorption in the middle ear of rats.
Laminaria, a hygroscopic seaweed, was used to induce pressure within the rat tympanic cavity. Resorption of the bulla and cochlear walls occurred in all animals within 2 weeks. Cochlear fistulas were observed in four of nine animals after 2 weeks and in nine of 11 animals after 3 weeks. Preswelled laminaria inserted in the same area induced minimal bone resorption after 2 and 3 weeks. In animals given indomethacin following insertion of laminaria, both granulation-tissue formation and bone resorption were inhibited. Collagenase appeared localized in the inflammatory granulation tissue in the bone-resorption area, especially in fibroblasts, mononuclear cells, and osteoclasts. Results of this study suggested that pressure created by laminaria caused bone resorption by stimulating osteoclasts and granulation tissue.
D000818:Animals; D001862:Bone Resorption / Q000187:drug effects / Q000473:pathology; D004432:Ear, Middle / Q000473:pathology / Q000503:physiopathology*; D006097:Granulation Tissue / Q000473:pathology; D007213:Indomethacin / Q000494:pharmacology; D008297:Male; D011312:Pressure; D051381:Rats; D011916:Rats, Inbred F344; D013701:Temporal Bone / Q000473:pathology*; D013997:Time Factors
D007213:Indomethacin