Protective effect of adeno-associated virus vector mediated heme oxygenase-1 overexpression on retinitis pigmentosa in rats

Objective

To investigate the protective effect of adeno-associated virus (AAV) vector-mediated heme oxygenase-1 (HO-1) gene overexpression on retinitis pigmentosa (RP) models in rats.

Methods

Eighty healthy male SD rats were selected and randomized into the blank control group, RP model group, AAV-GFP group and AAV-HO-1-GFP group, with 20 rats in each group.The RP model was established via tail vein injection of 1% sodium iodate solution at the dose of 50 mg/kg.Rats in the RP model group, AAV-GFP group and AAV-HO-1-GFP group were subretinally injected with normal saline, AAV-GFP virus and AAV-HO-1-GFP virus according to grouping.Rats in the blank control group were administrated with subretinal injection of equal volume of normal saline.The eyeballs of rats were enucleated on 14th day after molding.The retinal structure and thickness were detected by hematoxylin-eosin staining; apoptosis in retinal tissue was detected by TUNEL assay; the expression levels of cysteinyl aspartate specific proteinase 3 (caspase 3), B-lymphoma-2 (bcl-2) and HO-1 protein in rats retina was identified by Western blot.The use and care of the animals complied with the Statement of the Association for Research in Vision and Ophthalmology (ARVO). The study protocol was approved by an Ethics Committee of The Second Affiliated Hospital of Fujian Medical University (No.202188).

Results

Hematoxylin-eosin staining results showed normal retinal structure in the blank control group, obvious retinal structure damage with thinned and wavy outer nuclear layer in the RP model group and AAV-GFP group, and mild retinal structure damage with slightly thinned outer nuclear layer in the AAV-HO-1-GFP group.Compared with the blank control group, the outer nuclear layer was significantly thinner in the RP model group and AAV-GFP group (both at P<0.05). Relative expression level of HO-1 protein in the RP model group, AAV-GFP group, and AAV-HO-1-GFP group was 0.76±0.21, 0.76±0.16, 0.92±0.05, respectively, which were all significantly higher than 0.48±0.25 in the blank control group (all at P<0.05). The relative expression level of HO-1 protein in the AAV-HO-1-GFP group was significantly higher than that in the RP model group and the AAV-GFP group (both at P<0.05). There were significant differences in apoptosis rate, the relative expression levels of bcl-2 and caspase 3 protein among the four groups (F=1 596.333, 1 043.806, 364.331; all at P<0.01). The apoptosis rate and the relative expression level of caspase 3 were significantly higher, and the relative expression level of bcl-2 was lower in the RP model group and AAV-GFP group than those in the AAV-HO-1-GFP group (all at P<0.05).

Conclusions

AAV-mediated overexpression of HO-1 gene can protect the retina of RP rats.

Key words:

Heme oxygenase-1; Retinitis pigmentosa; Adeno-associated virus; Apoptosis