Abran D, Varma D R, Chemtob S
Centre de Recherche, Hôpital Sainte-Justine, Montreal, Quebec, Canada.
Am J Physiol. 1995 Feb;268(2 Pt 2):H628-32. doi: 10.1152/ajpheart.1995.268.2.H628.
The vasomotor effects of three peroxides (H2O2, cumene hydroperoxide, and t-butyl hydroperoxide) on the retinal vasculature, as well as the role of thromboxane in these effects, were studied using time-frame photography of isolated eyecup preparations from newborn and adult pigs. All three peroxides caused constriction of retinal arteries and veins, and these effects were greater in the newborn than in the adult. The cyclooxygenase inhibitor indomethacin, the thromboxane synthase blocker CGS-13080, and the thromboxane receptor blockers GR-32191B and L-670,596 inhibited the peroxide-induced vasoconstriction. The peroxides also increased thromboxane levels in the retina, and this increase was greater in newborn than in adult tissues. Both indomethacin and CGS-13080 prevented the peroxide-induced increase in retinal thromboxane. The thromboxane analogue U-46619 also produced constriction of newborn and adult retinal vessels, but its effects on the retinal veins of newborn pigs were less than those on adult veins. Data indicate an important role for increased production of thromboxane in the relative increase in the vasoconstrictor effects of peroxides on the newborn retinal vasculature. These findings suggest that the vasoconstriction and occlusion after oxidative stresses, which precede retinal neovascularization, are mediated by thromboxane.
利用新生猪和成年猪分离眼杯制剂的时间框架摄影技术，研究了三种过氧化物（过氧化氢、氢过氧化异丙苯和叔丁基过氧化氢）对视网膜血管系统的血管舒缩作用以及血栓素在这些作用中的作用。所有三种过氧化物均引起视网膜动脉和静脉收缩，且这些作用在新生猪中比成年猪中更明显。环氧化酶抑制剂吲哚美辛、血栓素合酶阻滞剂CGS - 13080以及血栓素受体阻滞剂GR - 32191B和L - 670596均抑制过氧化物诱导的血管收缩。过氧化物还增加了视网膜中的血栓素水平，且这种增加在新生组织中比成年组织中更明显。吲哚美辛和CGS - 13080均能阻止过氧化物诱导的视网膜血栓素增加。血栓素类似物U - 46619也可引起新生猪和成年猪视网膜血管收缩，但其对新生猪视网膜静脉的作用小于对成年猪静脉的作用。数据表明，血栓素生成增加在过氧化物对新生猪视网膜血管系统血管收缩作用的相对增加中起重要作用。这些发现提示，在视网膜新生血管形成之前的氧化应激后发生的血管收缩和阻塞是由血栓素介导的。
