Inhibitory effect of necrostatin-1 on necroptosis of retinal ganglion cells in rats with acute ocular hypertension

Objective

To investigate the inhibitory effect of specific inhibitor of necroptosis necrostatin-1 (Nec-1) on necroptosis of retinal ganglion cells (RGCs) in rats with acute ocular hypertension.

Methods

Twenty-four adult male Sprague Dawley rats were randomly divided into normal control group, model control group, Nec-1 treatment group and negative control group by random number table method, with 6 rats in each group.High intraocular pressure (IOP)-induced ischemia and reperfusion model was established through anterior chamber irrigation of 0.9% sodium chloride solution in left eyes of the rats, raising the IOP to 110 mmHg (1 mmHg=0.133 kPa) for 60 minutes.Nec-1 (4 mmol/L, 2 μl) or dimethyl sulfoxide (2 μl) was intravitreally injected immediately in Nec-1 treatment group and negative control group following modeling, respectively, according to grouping.No intervention was administered to the normal control group.Paraffin sections of rat retinas of the left eyes in different groups were prepared seven days after modeling.The retinal structure was observed by hematoxylin-eosin staining, and the expression levels of thymocyte antigen-1 (Thy-1) and glial fibrillary acidic protein (GFAP) were detected via immunohistochemical staining.All animal experiments were approved by an Ethics Committee of Tianjin Union Medical Center (No.2017 Quick audit C01).

Results

Seven days after modeling, compared with normal control group, the retinal nerve fiber layer was thinner in model control group and negative control group, and the RGCs were arranged loosely, and cells in the inner nuclear layer were reduced and arranged disorderly, and cells in the outer nuclear layer were normal or enlarged.Compared with model control group and negative control group, the nerve fiber layer was thickened and the number of RGCs was significantly increased in Nec-1 treatment group.The number of Thy-1-positive RGCs was decreased in model control group, negative control group and Nec-1 treatment group than normal control group, and there were more Thy-1-positive RGCs in Nec-1 treatment group than model control group and negative control group.The integrated absorbance (A) value of GFAP protein in normal control group, model control group, negative control group and Nec-1 treatment group was 47.209±15.311, 116.220±18.194, 116.382±19.020, 92.818±10.236, respectively, showing statistically significant differences among them (F=24.675, P<0.001). The integrated A value of GFAP protein was significantly increased in model control group, negative control group and Nec-1 treatment group than normal control group, and the integrated A value of GFAP protein in Nec-1 treatment group was lower than that in model control group and negative control group, with statistically significant differences (all at P<0.05).

Conclusions

Nec-1 can promote RGCs survival by inhibiting the necroptosis of RGCs in rats with acute intraocular hypertension.

Ocular hypertension, acute; Retinal ganglion cells; Necrostatin-1; Necroptosis; Glial fibrillary acid protein