Mastrodimou Niki, Lambrou George N, Thermos Kyriaki
Laboratory of Pharmacology, Department of Basic Sciences, Faculty of Medicine, University of Crete, Heraklion, Crete, 71110, Greece.
Naunyn Schmiedebergs Arch Pharmacol. 2005 Jan;371(1):44-53. doi: 10.1007/s00210-004-1011-9. Epub 2005 Jan 12.
This study investigated the neuroprotective effect of somatostatin, cortistatin and agonists at somatostatin(2) (sst(2)) receptors in retinal explants subjected to chemical ischaemia. Eyecups of female Sprague-Dawley rats (250-300 g) were immersed in PBS buffer or PBS containing iodoacetic acid (IAA; 0.5, 5, 50, 100 mM) and sodium cyanide (NaCN; 2.5, 25, 250, 500 mM) (chemical ischaemia solution) for 15, 30, 45, 60, 120 min (pilot study). Subsequently, eyecups were incubated with (1) PBS, (2) chemical ischaemia solution (5 mM IAA/25 mM NaCN) or (3) somatostatin, cortistatin, BIM23014 or MK678 (0.1, 1, 10 microM) together with the chemical ischaemia solution for 60 min, followed by a second 60-min incubation in PBS (control and ischaemia groups) or ligands in PBS (neuroprotection groups). The eyecups were subsequently fixed and sectioned for immunohistochemistry. Treatment of the eyecups with IAA/NaCN (5/25 mM) for 60 min abolished choline acetyltransferase (ChAT), tyrosine hydroxylase and brain nitric oxide synthase immunoreactivity in the inner nuclear, inner plexiform and ganglion cell layers. It also abolished protein kinase C immunoreactivity in rod bipolar cells and terminals, but did not damage ganglion cells labelled for microtubule-associated protein-1. TUNEL staining provided evidence of cell death in the ischaemic retina. Cortistatin, BIM23014 and MK678 attenuated the retinal damage caused by the chemical ischaemia in a concentration dependent manner. The ligands afforded approximately 58, 76 and 49% neuroprotection, respectively, of the ChAT immunoreactive cells. These results demonstrate that somatostatin analogues can protect the retina from ischaemic damage. The chemical ischaemia model is presently employed for the elucidation of the mechanisms involved in the neuroprotection.
本研究调查了生长抑素、促皮质素以及生长抑素（2）（sst(2)）受体激动剂在化学性缺血视网膜外植体中的神经保护作用。将雌性Sprague-Dawley大鼠（250 - 300 g）的眼杯浸入PBS缓冲液或含有碘乙酸（IAA；0.5、5、50、100 mM）和氰化钠（NaCN；2.5、25、250、500 mM）的PBS（化学性缺血溶液）中15、30、45、60、120分钟（预实验）。随后，眼杯与（1）PBS、（2）化学性缺血溶液（5 mM IAA/25 mM NaCN）或（3）生长抑素、促皮质素、BIM23014或MK678（0.1、1、10 microM）以及化学性缺血溶液一起孵育60分钟，然后在PBS中再孵育60分钟（对照组和缺血组）或在含配体的PBS中孵育（神经保护组）。随后将眼杯固定并切片用于免疫组织化学分析。用IAA/NaCN（5/25 mM）处理眼杯60分钟可消除内核层、内网层和神经节细胞层中胆碱乙酰转移酶（ChAT）、酪氨酸羟化酶和脑一氧化氮合酶的免疫反应性。它还消除了视杆双极细胞及其终末中蛋白激酶C的免疫反应性，但未损伤标记有微管相关蛋白-1的神经节细胞。TUNEL染色提供了缺血视网膜中细胞死亡的证据。促皮质素、BIM23014和MK678以浓度依赖性方式减轻了化学性缺血引起的视网膜损伤。这些配体分别对ChAT免疫反应性细胞提供了约58%、76%和49%的神经保护作用。这些结果表明生长抑素类似物可保护视网膜免受缺血性损伤。目前采用化学性缺血模型来阐明神经保护所涉及的机制。
