Bone actions of the forgotten estrogen, Estrone

MARIA BELÉN RAUSCHEMBERGER; MASSHEIMER, VIRGINIA LAURA; MARIA CARLA CRESCITELLI

Buenos Aires

Congreso; Reunión Conjunta de Sociedades de Biociencias; 2017

Sociedades de Biociencias

Estrogens play an important role in bone remodeling. Although estradiol action has been the subject of intensive investigation, little is known about the contribution of the other major endogenous estrogen, estrone (E1). The aim of this work was to evaluate the effect of E1 on bone cells, particularly the modulation of osteoblasts (OB) maturation. Murine calvarial pre-OB were cultured for 3-15 days and exposed to E1 (10-8 ? 10-10M) in the last 48h. OB characterization was performed by the measurement of bone markers, using RT-PCR technique. mRNA levels for BMP-2 and Runx-2 were detected in all time of culture (3-15 days). Indeed the expression of both types of ER (á andâ) was also detected. In 15 days OB culture, E1 significantly increased cell proliferation (0,68±0,09 vs 0,49±0,09, E1 vs C, p˂0,001 in MTT assay). These results were confirmed by cell counting (41% above C, p˂0,05). Since mature OB exhibited high level of alkaline phosphatase activity (ALP) and enriched extracellular calcium deposition, we evaluated the effect of E1 on both parameters. E1 enhanced ALP (15% a/C, p< 0,01) and increased the number and size of calcification nodules in the extracellular matrix (one fold p˂0,005, Alizarin staining), with major effect at longer period of cell culture. Accordingly with this, markedly decreased in calcium content was detected in aliquots of cultured medium (205±25 vs 118±23, C vs E1, p˂0,001). Indeed E1 modulates extracellular collagen deposition visualized by Sirius red staining. On genes related with OB maturation, E1 treatment elicited 2 fold increase in Runx-2 mRNA levels, with higher effects at 3-5 days of culture (p