Alteration Of Type I Collagen Microstructure Induced By Estrogen Depletion Can Be Prevented With Drug Treatment

Two independent biological replicates of estrogen depletion were employed with differing drug treatment conditions. Data Set I consisted of 9-month-old New Zealand white female rabbits treated as follows: sham-operated (n = 11), ovariectomized (OVX; n = 12), OVX+200 mu g kg(-1) alendronate (ALN), 3 x a week for 27 weeks (n = 12) and OVX+10 mg kg(-1) Cathepsin-K inhibitor (CatKI) daily for 27 weeks. Data Set II consisted of 6-month-old New Zealand white female rabbits that were sham-operated (n = 12), OVX (n = 12) or OVX+0.05mg kg(-1) 17 beta-estradiol (ERT) 3 x a week for 13 weeks (n = 12). Samples from the cortical femur were polished and demineralized to make them suitable for atomic force microscopy (AFM) imaging. Type I collagen fibrils present in bundles or sheets, running parallel to each other, were combined into a class termed Parallel. Fibrils present outside of such structures, typically in images with an angular range of non-parallel fibrils, were combined into a class termed Oblique. The percentage of fibrils coded as Parallel for Sham animals in Data Sets I and II was 52% and 53%, respectively. The percentage of fibrils coded as Parallel for OVX animals in Data Sets I and II was 35% in both cases. ALN and ERT drug treatments reduced the change from 18 to 12%, whereas CatKI treatment reduced the change to 5%.