Objective To explore the possible mechanism of vitamin C in alleviating macular degeneration in rats by regulating the function of macrophages.

Methods SD rats were injected with sodium iodate into the tail vein to create a macular degeneration model, and vitamin C was given to the rats by gavage. Thirty SD rats were randomly divided into normal group, model group and treatment group after adaptive feeding for one week, with 10 rats in each group. The normal group was not given any treatment measures; in the treatment group, 40 mg/kg sodium iodate was injected into the tail vein to establish the model, and 100 mg/kg vitamin C was given by gavage once a day after the start of experiment; in the model group, 40 mg/kg sodium iodate was injected into the tail vein to establish the model, and the equal volume of normal saline was given by gavage every day after the start of experiment. After the treatment, the electroretinogram recording system was used to detect retinal potential of rats, the retinal structure, the number of retinal external nuclear cells and the epithelial layer of retinal pigment cells were detected by hematoxylin-eosin staining (HE staining), and flow cytometry was used to detect CD36 and CD206 in retinal macrophages.

Results Vitamin C was able to alleviate the retinal damage in rats. The number of retinal external nuclear cells in the model group was (72.90±15.60) cells per field of vision, which was lower than (126.40±13.60) cells per field of vision in the treatment group (P < 0.01). The epithelial layer of retinal pigment cells in the model group was (1.56±0.93) layers per field of vision, which was significantly lower than (3.49±0.88) layers per field of vision in the treatment group (P < 0.05). Vitamin C was able to increase the retinal potential of age-related macular degeneration (AMD) rats, protect the retinal function of rats, and alleviate the progression of AMD. Vitamin C was able to increase the ratio of CD36 positive cells and reduce the ratio of CD206 positive cells, which was reflected as follows: the ratio of CD36 positive cells of retinal macrophages in the model group was (33.98±6.86)%, which was significantly lower than (46.86±3.83)% in the treatment group (P < 0.01). The ratio of CD206 positive cells of retinal macrophages in the model group was (43.59±6.51)%, which was significantly higher than (31.52±4.08)% in the treatment group (P < 0.01).

Conclusion Vitamin C can alleviate macular degeneration in rats by enhancing phagocytic capacity of retinal macrophages and inhibiting M2 polarization of macrophages.