实验性扁平部玻璃体切割术前、后视网膜前氧分压梯度。

Laboratory of Retinal Neurobiology and Vascular Physiology, Department of Ophthalmology, University of Geneva, Geneva, Switzerland.

Retina. 2013 Jan;33(1):170-8. doi: 10.1097/IAE.0b013e318261a6b5.

PURPOSE

To evaluate preretinal partial pressure of oxygen (PO2) gradients before and after experimental pars plana vitrectomy.

METHODS

Arteriolar, venous, and intervascular preretinal PO2 gradients were recorded in 7 minipigs during slow withdrawal of oxygen-sensitive microelectrodes (10-μm tip diameter) from the vitreoretinal interface to 2 mm into the vitreous cavity. Recordings were repeated after pars plana vitrectomy and balanced salt solution (BSS) intraocular perfusion.

RESULTS

Arteriolar, venous, and intervascular preretinal PO2 at the vitreoretinal interface were 62.3 ± 13.8, 22.5 ± 3.3, and 17.0 ± 7.5 mmHg, respectively, before vitrectomy; 97.7 ± 19.9, 40.0 ± 21.9, and 56.3 ± 28.4 mmHg, respectively, immediately after vitrectomy; and 59.0 ± 27.4, 25.2 ± 3.0, and 21.5 ± 4.5 mmHg, respectively, 2½ hours after interruption of BSS perfusion. PO2 2 mm from the vitreoretinal interface was 28.4 ± 3.6 mmHg before vitrectomy; 151.8 ± 4.5 mmHg immediately after vitrectomy; and 34.8 ± 4.1 mmHg 2½ hours after interruption of BSS perfusion. PO2 gradients were still present after vitrectomy, with the same patterns as before vitrectomy.

CONCLUSION

Preretinal PO2 gradients are not eliminated after pars plana vitrectomy. During BSS perfusion, vitreous cavity PO2 is very high. Interruption of BSS perfusion evokes progressive equilibration of vitreous cavity PO2 with concomitant progressive return of preretinal PO2 gradients to their previtrectomy patterns. This indicates that preretinal diffusion of oxygen is not altered after vitrectomy. The beneficial effect of vitrectomy in ischemic retinal diseases or macular edema may be related to other mechanisms, such as increased oxygen convection currents or removal of growth factors and cytokines secreted in the vitreous.

目的

评估实验性经平坦部玻璃体切除术前后视网膜前局部氧分压（PO2）梯度。

方法

在 7 只小型猪中，用 10μm 尖端直径的氧敏感微电极缓慢从玻璃体视网膜界面退出至玻璃体腔 2mm 处，记录动、静脉和血管间视网膜前 PO2 梯度。在经平坦部玻璃体切除术后和平衡盐溶液（BSS）眼内灌注后重复记录。

结果

玻璃体切除术前，视网膜玻璃体界面处的动、静脉和血管间视网膜前 PO2 分别为 62.3±13.8mmHg、22.5±3.3mmHg 和 17.0±7.5mmHg；玻璃体切除术后即刻分别为 97.7±19.9mmHg、40.0±21.9mmHg 和 56.3±28.4mmHg；BSS 灌注中断 2 小时半后分别为 59.0±27.4mmHg、25.2±3.0mmHg 和 21.5±4.5mmHg。玻璃体视网膜界面 2mm 处 PO2 在玻璃体切除术前为 28.4±3.6mmHg；玻璃体切除术后即刻为 151.8±4.5mmHg；BSS 灌注中断 2 小时半后为 34.8±4.1mmHg。玻璃体切除术后仍存在视网膜前 PO2 梯度，其模式与玻璃体切除术前相同。

结论

经平坦部玻璃体切除术后视网膜前 PO2 梯度并未消除。在 BSS 灌注期间，玻璃体腔 PO2 非常高。BSS 灌注中断引起玻璃体腔 PO2 逐渐平衡，同时视网膜前 PO2 梯度逐渐恢复到玻璃体切除术前的模式。这表明玻璃体切除术后氧的视网膜前弥散未改变。玻璃体切除术在缺血性视网膜疾病或黄斑水肿中的有益作用可能与其他机制有关，例如增加氧对流电流或去除玻璃体中分泌的生长因子和细胞因子。