EXPRESSION OF GELATINASES WITHIN THE TRABECULAR BONE COMPARTMENT OF OVARIECTOMIZED AND PARATHYROIDECTOMIZED ADULT FEMALE RATS

Ovariectomized (ovx) and parathyroidectomized (ptx) rat models of dist urbed bone metabolism have been widely used in evaluating bone changes resulting from hormonal depletion, and are characterized by elevated and depressed bone turnover, respectively, We report here the expressi on of gelatinases extracted from native trabecular bone in these model s. Nine-month-old female Sprague-Dawley rats were sacrificed after 3 w eeks following ovx or 10 days post ptx to determine the influence of t hese procedures on the levels of proximal tibial bone tissue gelatinas es. Identification and quantitation of these enzymes were performed vi a gelatin gel zymography of native tissue extracts and laser densitome try of developed gels, respectively, In the ptx model, a reduction in tissue levels of pro- and active-MMP-2 and a 45 kDa activated fragment was seen, whereas ovx exhibited significant increases in these enzyme s, The MMPs are therefore clearly under the influence of factors known to modulate bone remodeling in vivo, The study of MMP levels directly extracted from bone using these experimental models may assist in dev eloping management regimes for metabolic bone diseases through the use of drugs aimed at controlling turnover. (C) 1997 by Elsevier Science Inc.