Dynamic regulation of vasoactive intestinal polypeptide in the retina of guinea pigs with experimentally induced myopia.

Abstract

OBJECTIVE: This study aimed to examine the dynamic expression patterns of vasoactive intestinal polypeptide (VIP) in the retina of guinea pigs and explore its potential role as a visual signaling molecule in ocular development and the pathogenesis of myopia. METHODS: Three-week-old healthy tricolored guinea pigs were randomly assigned to either a normal control (NC) group or an experimental group. In the experimental group, the right eye was subjected to form-deprivation myopia (FDM), while the left eye served as a self-control group (SC). Diopter and axial length measurements were performed on all groups at baseline (day 0) and subsequently on days 10, 20, and 30. Following each measurement, 10 guinea pigs from each group were randomly selected for euthanasia. Eyes were fixed in a specialized fixative solution and processed for paraffin embedding and sectioning. Histomorphological changes were assessed using H&E staining, while immunohistochemistry and in situ hybridization were used to quantify VIP protein and mRNA expression levels. RESULTS: A progressive increase in myopia severity and axial elongation was observed in all groups over time. The FDM group exhibited a significantly greater myopic shift compared to the NC and SC groups at all time points (all p&#xa0;<&#xa0;0.05). Retinal VIP mRNA and protein expression levels increased progressively with age in all groups (p&#xa0;<&#xa0;0.01). At each time point, expression levels in the FDM group were significantly higher than those in the NC and SC groups, whereas no significant difference was detected between the SC and NC groups. CONCLUSION: The findings of this study indicate a correlational relationship between the VIP signaling pathway and ocular development as well as myopia progression, with VIP upregulation occurring alongside axial elongation.