玻璃体切割术前、后兔晶状体和玻璃体中的氧张力

Oxygen tension in the rabbit lens and vitreous before and after vitrectomy.

作者信息

Barbazetto Irene A, Liang Jianhong, Chang Stanley, Zheng Lei, Spector Abraham, Dillon James P

机构信息

E.S. Harkness Eye Institute, Columbia University, New York, NY 10032, USA.

出版信息

Exp Eye Res. 2004 May;78(5):917-24. doi: 10.1016/j.exer.2004.01.003.

DOI:10.1016/j.exer.2004.01.003

PMID:15051473

Abstract

Oxygen is believed to be one of the potential causative agents for the development of nuclear cataract following vitrectomy. The aim of this study was to determine the partial pressure of oxygen (pO2) in different compartments of the rabbit eye, and to describe the changes following vitrectomy. Twenty-six rabbits (3.5-5.3 kg) were anesthetized and oxygen tension was probed using a fiber-optic oxygen sensor system (optode). A micromanipulator was employed to ascertain the exact position of the probe within the eye. Measurements were taken pre- and post-vitrectomy at several defined positions within the vitreous, the lens and the anterior chamber. Follow-up measurements were performed 2 and 8 weeks after vitrectomy. The contralateral eye served as a control. Measurements in the normal rabbit eye showed that oxygen tension in the globe is asymmetrical with the lowest pO2 in the nucleus of the lens (10.4 mmHg+/-3.0). The region of the lens near the posterior capsule has an oxygen tension close to the values of the vitreous directly behind the posterior capsule (12.4 mmHg+/-3.1). The highest pO2 within the posterior compartment of the eye was measured close to the retinal surface (40-l60 mmHg) depending on neighboring large vessels. The tension drops off rapidly to 20 mmHg some 0.5 mm from the retina. From that position to the posterior surface of the lens there is a shallow gradient of decreasing pO2. Immediately following vitrectomy the pO2 in the BSS replacement varied from ca. 90-140 mmHg, and decreased over approximately 30 min. to levels that were 2-3 times that of normal vitreous. Two weeks after vitrectomy the pO2 values in the lens were 2-3 times as high as in the control eye (p < 0.05). In addition there is no longer a gradient in the vitreous cavity, except close to the retina. Eight weeks after vitrectomy, pO2 levels in the lens were decreased but still remained higher than in the normal eye (13.83 mmHg+/-0.02). The pO2 gradient in the vitreous was not detectable anymore. Overall the results provide evidence that oxygen levels in the lens increase significantly after vitrectomy in rabbits. If this occurs in humans it may contribute to cataract formation following surgery.

摘要

氧气被认为是玻璃体切除术后核性白内障发生发展的潜在致病因素之一。本研究的目的是测定兔眼不同腔室中的氧分压（pO₂），并描述玻璃体切除术后的变化。26只兔子（3.5 - 5.3千克）麻醉后，使用光纤氧传感器系统（光极）探测氧张力。采用显微操纵器确定探头在眼内的确切位置。在玻璃体切除术前和术后，于玻璃体、晶状体和前房内的几个特定位置进行测量。玻璃体切除术后2周和8周进行随访测量。对侧眼作为对照。正常兔眼的测量结果显示，眼球内的氧张力不对称，晶状体核内的pO₂最低（10.4 mmHg±3.0）。晶状体后囊附近区域的氧张力接近后囊后方玻璃体的值（12.4 mmHg±3.1）。根据相邻大血管情况，眼后房内最高的pO₂在靠近视网膜表面处测得（40 - 60 mmHg）。从视网膜起约0.5毫米处，张力迅速降至20 mmHg。从该位置到晶状体后表面，pO₂呈浅梯度下降。玻璃体切除术后即刻，平衡盐溶液替代液中的pO₂约为90 - 140 mmHg，并在约30分钟内降至正常玻璃体2 - 3倍的水平。玻璃体切除术后2周，晶状体中的pO₂值是对照眼的2 - 3倍（p < 0.05）。此外，除靠近视网膜处外，玻璃体腔内不再存在梯度。玻璃体切除术后8周，晶状体中的pO₂水平降低，但仍高于正常眼（13.83 mmHg±0.02）。玻璃体中的pO₂梯度不再可测。总体而言，结果表明兔玻璃体切除术后晶状体中的氧水平显著升高。如果在人类中也如此，可能会导致术后白内障形成。