Sex‐related differences in the visual function of an animal model of type 1 diabetes

Abstract

Aims/Purpose: Recent basic and clinical research evidence suggests that male–female differences may influence retinal function and structure. It is also well‐established that diabetes affects retinal function. This work aimed to assess whether type 1 diabetes differentially affects neuroretinal function in male and female Wistar rats.Methods: To induce type 1 diabetes, male and female Wistar rats were injected (i.p.) with streptozotocin (65 mg/kg). Electroretinograms (ERGs) were recorded before and 1, 2, and 4 weeks after diabetes induction (n = 12–13 animals/group). To assess the effect of chronic hyperglycemia on the content of molecular components of the blood‐retinal barrier (BRB), specific tight junction proteins were assessed by Western Blotting. Neuroinflammation was evaluated by measuring the retinal levels of pro‐inflammatory cytokines.Results: Some sex‐related changes in retinal function were detected in the diabetic animals. Overall, in male diabetic rats, compared to control male rats, the differences found under scotopic conditions were mainly in the positive scotopic threshold response (pSTR), with decreased amplitudes (at weeks 2 and 4), and higher latencies (at weeks 1 and 4). In contrast, diabetic female rats, compared to control females, presented a higher increase in the latency value of the negative STR (nSTR; at weeks 1 and 4), a‐wave (at weeks 1, 2, and 4), and oscillatory potentials 2, 3, and 4 (at weeks 1, 2, and 4). Under photopic conditions, male diabetic rats showed higher implicit time values of the fundamental flicker wave (at week 4) and a decrease in the amplitude of the flicker 2nd harmonic (at week 4) compared to control males. Conversely, in diabetic female rats, there were no differences in these parameters compared to control female rats. Concerning the BRB and neuroinflammation, no changes were found in diabetic males and females compared to their respective controls.Conclusions: Our findings suggest that type 1 diabetes differentially affects the retinal function in male and female Wistar rats.Support: FCT‐Portugal: PEst UIDB/04539/2020 and UIDP/04539/2020; 2020.07432.BD.