ABSTRACT

Purpose/Aim of the study: The role of estrogen (E) in the regulation of bone turnover in women is well established, though the contributions of E versus testosterone (T) in the control of bone turnover in men are poorly understood. The aim of this study was to examine the association between chronic treatment with letrozole, a nonsteroidal inhibitor blocking the aromatase activity and thus the conversion of androgens into estrogens, and cortical bone morphology in the femur and humerus of male adult rats.

Materials and Methods: Adult male rats were treated with letrozole for 6 months and the body and femur weight, morphology, collagen structure, blood serum, and bone tissue concentrations of calcium and magnesium were examined.

Results: Long-term aromatase inhibition resulted in a decrease in femur mass, a wavelike arrangement of bone and lamellae with an altered organization of collagen in compact bone, a increased concentration of calcium in blood serum, and no change in calcium bone tissue concentration, magnesium serum, or bone tissue concentration. MicroCT study of the humerus revealed significant decreases of whole bone tissue volume, cortical bone thickness, cortical bone volume, and external cortical bone thickness with letrozole treatment.

Conclusion: Chronic treatment with letrozole affected cortical bone structure and produced histomorphological changes in male rat bone similar to that observed in the aging processes.

摘要

研究目的/目的：雌激素 (E) 在调节女性骨转换中的作用已得到充分证实，尽管 E 与睾酮 (T) 在控制男性骨转换中的作用知之甚少。本研究的目的是检查来曲唑的慢性治疗与雄性成年大鼠股骨和肱骨皮质骨形态之间的关系，来曲唑是一种非甾体抑制剂，可阻断芳香酶活性，从而阻止雄激素转化为雌激素。

材料与方法：成年雄性大鼠用来曲唑治疗6个月，检查体重和股骨重量、形态、胶原结构、血清和骨组织中钙和镁的浓度。

结果：长期抑制芳香化酶导致股骨质量减少，骨和薄片呈波浪状排列，致密骨中胶原蛋白组织发生改变，血清中钙浓度增加，钙骨组织浓度没有变化，镁血清或骨组织浓度。肱骨的显微 CT 研究显示，来曲唑治疗后整个骨组织体积、皮质骨厚度、皮质骨体积和外部皮质骨厚度显着降低。

结论：长期使用来曲唑治疗会影响皮质骨结构，并在雄性大鼠骨骼中产生与衰老过程中观察到的相似的组织形态学变化。