Importance of estrogen insufficiency time in the efficacy of the bone response to hormonal therapy in experimental chronic renal insufficiency

• Published in: Nefrología Vol. 23 Suppl 2; pp. 84 - 90
• Main Authors: Rodríguez Rodríguez, A, Naves Díaz, M, Díaz Corte, C, González Carcedo, A, Fernández Coto, T, Cannata Andía, J B
• Format: Journal Article
• Language: Spanish
• Published: Spain 2003
• Subjects: Absorptiometry, Photon; Animals; Bone and Bones - metabolism; Bone and Bones - pathology; Bone Density; Calcitriol - administration & dosage; Calcitriol - therapeutic use; Chronic Kidney Disease-Mineral and Bone Disorder - etiology; Chronic Kidney Disease-Mineral and Bone Disorder - metabolism; Chronic Kidney Disease-Mineral and Bone Disorder - pathology; Chronic Kidney Disease-Mineral and Bone Disorder - prevention & control; Disease Models, Animal; Drug Therapy, Combination; Estradiol - administration & dosage; Estradiol - therapeutic use; Estrogen Replacement Therapy; Estrogens - deficiency; Female; Kidney Failure, Chronic - complications; Kidney Failure, Chronic - metabolism; Nephrectomy; Ovariectomy; Predictive Value of Tests; Rats; Rats, Sprague-Dawley; Time Factors; Treatment Outcome
• ISSN: 0211-6995

Bone disease develops relatively early in the development of CRF. The aim of this study was to evaluate the repercussion of estrogen insufficiency and the effectiveness of hormonal replacement therapy, after different periods of estrogen deprivation, on bone metabolism in an animal model with chronic renal failure and ovariectomy. A secondary purpose was to evaluate the effectiveness of bone densitometry for predicting changes in bone mass for comparison with bone histomorphometry. We used Sprague-Dawley rats with chronic renal failure and ovariectomy performed at the same time. Animals were divided into two phases according to the period of estrogen insufficiency, 4 weeks in the long estrogen insufficiency period and 1 week in the short estrogen insufficiency period. In both phases, the animals were divided into four treatment groups receiving placebo (corn oil), 17 beta-estradiol (15 micrograms/kg body weight/day), calcitriol (10 ng/kg body weight/day) or the combined treatment with estradiol and calcitriol. In both phases, a group of animals with chronic renal failure (normal ovarian function) was used as a control group. The period of treatment was 8 weeks. After this period the animals were sacrificed. This model emphasizes the importance of the period of estrogen insufficiency in the efficiency of the treatment. Four weeks of estrogen insufficiency resulted in an significant loss of trabecular bone, and less possibility of recovery. After one week of estrogen deprivation a response to the treatment was observed. The utilization of bone densitometry allowed to reproduce changes in bone mass observed afterwards by histomorphometric analysis.