N-乙酰-5-羟色胺对视网膜缺血-再灌注损伤大鼠视网膜Fas、 FasL蛋白表达的影响

Objective: To investigate the effects of N-acetylserotonin (NAS) on the expression of Fas and FasL in the retina of rats with retina ischemia-reperfusion injury (RIRI). Methods The RIRI rat model was established by ocular hypertension method. Adult male Sprague-Dawley rats were randomly divided into normal control group (n=6), RIRI group (n=24) and NAS group (n=24). The NAS group received intraperitoneal injection of NAS 30 min before RIRI, and the RIRI group received intraperitoneal injection of the same amount of normal saline at the same time. The groups were divided into 6 h, 12 h, 24 h and 72 h subgroups according to the time of modeling. Morphological changes of retina in each group were observed under light microscope by HE staining, and recorded the retinal thickness and the number of retinal ganglion cells in each group. Immunohistochemical staining was used to detect the effect of NAS on the expression of Fas and FasL protein in the retina of RIRI rats. Results HE staining showed that the cells in the retina of normal rats had clear boundaries, normal morphology, and neatly arranged nerve cells. In the RIRI group, edema appeared in the retina at 6 h after reperfusion, and the ganglion cell layer and inner nuclear layer were more obvious. The number of ganglion cells was lower than that in the normal group. Then the retinal edema was further aggravated and the ganglion cells continued to decrease. The degree of retinal edema in the NAS group was lower than that in the RIRI group at 6 h, 12 h and 24 h after reperfusion. The retinal thickness of the NAS group was thicker than the RIRI group at 72 h after reperfusion. The number of ganglion cells in the NAS group was higher than that in the RIRI group at each time point. The difference was statistically significant (all P<0.05). Immunohistochemical staining showed that almost no Fas+ cells were seen in the normal group. At 6 h after reperfusion, a small number of Fas+ cells began to appear in the retinal ganglion cells and inner nuclear layer of the RIRI group. At 12 h after reperfusion, the expression of retinal Fas+ cells in the RIRI group gradually increased. Retinal Fas+ cells reached a peak at 24 h after reperfusion, and brown positive staining cells were distributed in retinal ganglion cell layer, inner plexiform layer, inner nuclear layer and nerve fiber layer. Compared with 24 h after reperfusion, Retinal Fas+ cells was decreased at 72 h after reperfusion. The number of retinal Fas+ cells in the NAS group at 6 h, 12 h, 24 h, and 72 h after reperfusion was lower than that in the RIRI group. At 24 h after reperfusion, the number of Fas+ cells reached a high level and then decreased. The difference was statistically significant (all P<0.05). FasL full-layer low expression in the normal group. At 6 h after reperfusion in the RIRI group, a small number of FasL+ cells were present in the retinal ganglion cell layer and nerve fiber layer. FasL protein expression increased gradually at 12 h after reperfusion. The number of FasL+ cells reached a peak at 24 h after reperfusion. It was found that dark brown cell membrane and cytoplasmic staining cells were distributed in retinal ganglion cell layer, inner plexiform layer, inner nuclear layer and nerve fiber layer. The positive expression of FasL protein decreased gradually at 72 h after reperfusion. The number of retinal FasL+ cells in the NAS group at 6 h, 12 h, 24 h, and 72 h after reperfusion was less than that in the RIRI group at each time point. The difference was statistically significant (all P<0.05). Conclusion NAS can attenuate the damage of retinal cells induced by ischemia-reperfusion in rats by inhibiting the expression of Fas and FasL proteins in retinal cells of RIRI rats.