Medicine and Health Sciences Commons^™

Lumbar Vertebral Density And Mechanical Properties In Aged Ovariectomized Rats Treated With Estrogen And Norethindrone Or Norgestimate, Carla Vanin, Neil Maclusky, Debbie Chachra, Mehran Kasra, Marc Grynpas, Robert Casper

Debbie Chachra

OBJECTIVE: This study was designed to investigate the effects of estrogen alone or combined with two different progestins, norethindrone or norgestimate, on bone density and compressive mechanical properties in an aged rat model.

STUDY DESIGN: Twenty 11-month-old female Sprague-Dawley rats were sham operated (intact control) and 80 wee overiectomized. Three groups of 20 ovariectomized rats were implanted with Silastic silicon rubber (Dow Corning, Midland, Mich.) capsules containing 5% estradiol (wt/wt) in cholesterol. All rats in the intact control (group 1) and the ovariectomized (group 2) and the first of the overiectomized plus estrogen (group 3) groups were injected subcutaneously daily …

The Effect Of Different Hormone Replacement Therapy Regimens On The Mechanical Properties Of Rat Vertebrae, Debbie Chachra, M. Kasra, Carla Vanin, N. Maclusky, R. Casper, Marc Grynpas

Debbie Chachra

The purpose of this study was to examine the effects of estrogen replacement, in concert with three different progestin regimens, on the mechanical properties of rat lumbar vertebrae. Ninety-two Sprague-Dawley rats (11 months old) were divided into six groups for treatment. The first group was an intact control, the second group (OVX) was ovariectomized only, and the third group (estrogen-only) was ovariectomized and received continuous estrogen through a 17-estradiol implant. The remaining groups were ovariectomized and received estrogen and progestin (norethindrone, NET) therapy; 3 g of NET was injected daily (estrogen plus continuous NET), or 6 g of NET was …