Matrai Mate, Mericli Metin, Nadasy Gyorgy L, Szekeres Maria, Varbiro Szabolcs, Banhidy Ferenc, Acs Nandor, Monos Emil, Szekacs Bela
Institute of Human Physiology and Clinical Experimental Research, Faculty of Medicine, Semmelweis University, Budapest, Hungary.
J Biomech. 2007;40(5):1024-30. doi: 10.1016/j.jbiomech.2006.04.002. Epub 2006 May 30.
The prevalence of ischemic heart disease is lower in premenopausal females than in males of corresponding age. This should be related to gender differences in coronary functions. We tested whether biomechanical differences exist between intramural coronary resistance arteries of male and female rats. Intramural branches of the left anterior descending coronary artery (uniformly approximately 200microm in diameter) were isolated, cannulated and studied by microarteriography. Intraluminal pressure was increased from 2 to 90mmHg in steps and steady-state diameters were measured. Measurements were repeated in the presence of vasoconstrictor U46619 (10(-6)M) and the endothelial coronary vasodilator bradykinin (BK) (10(-6)M). Finally, passive diameters were recorded in calcium-free saline. A similar inner radius and a higher wall thickness (41.5+/-2.9microm vs. 31.4+/-2.7microm at 50mmHg in the passive condition, p<0.05) resulted in lower tangential wall stresses in male rats (18.9+/-1.9kPa vs. 24.9+/-2.5kPa at 50mmHg, p<0.05). Isobaric elastic modulus of vessels from male animals was significantly smaller at higher pressures. Vasoconstrictor response was significantly stronger in male than in female animals. Endothelial relaxations induced by BK were not different. This is the first demonstration that biomechanical characteristics of intramural coronary resistance arteries of a mammalian species are different in the male and female sexes. Higher wall thickness and higher vascular contractility in males are associated with similar endothelial function and larger high-pressure elasticity compared to females. These gender differences in biomechanics of coronary resistance arteries of rats may contribute to our better understanding the characteristic physiological and pathological differences in humans.
绝经前女性缺血性心脏病的患病率低于同龄男性。这可能与冠状动脉功能的性别差异有关。我们测试了雄性和雌性大鼠壁内冠状动脉阻力动脉之间是否存在生物力学差异。分离出左前降支冠状动脉的壁内分支（直径均匀约为200微米），插管并通过微血管造影术进行研究。管腔内压力逐步从2mmHg增加到90mmHg，并测量稳态直径。在存在血管收缩剂U46619（10^(-6)M）和内皮冠状动脉舒张剂缓激肽（BK）（10^(-6)M）的情况下重复测量。最后，在无钙盐水中记录被动直径。在被动状态下，雄性大鼠类似的内半径和更高的壁厚（50mmHg时为41.5±2.9微米对31.4±2.7微米，p<0.05）导致较低的切向壁应力（50mmHg时为18.9±1.9kPa对24.9±2.5kPa，p<0.05）。雄性动物血管在较高压力下的等压弹性模量明显较小。雄性动物的血管收缩反应明显强于雌性动物。BK诱导的内皮舒张没有差异。这是首次证明哺乳动物壁内冠状动脉阻力动脉的生物力学特征在雄性和雌性中存在差异。与雌性相比，雄性更高的壁厚和更高的血管收缩性与相似的内皮功能和更大的高压弹性相关。大鼠冠状动脉阻力动脉生物力学的这些性别差异可能有助于我们更好地理解人类特征性的生理和病理差异。
