Avaliação comportamental e eletrofisiológica do sistema visual em camundongos com anemia a partir de um modelo de colite aguda

Abstract

Inflammatory bowel diseases (IBD) are the main causes of anemia and iron deficiency and tend to affect metabolically active tissues distant from the inflammation areas, such as the retina. From this context, it is interesting to investigate the responsive behavior of the visual system through psychophysical and electrophysiological tests in animals with IBD. The main objective of the present work was to evaluate the behavioral and physiological changes of the visual system in mice with induced anemia, from an acute colitis model. For this purpose, 18 mice were used, divided into three groups: control; Colitis (induced by Dextran Sulfate Sodium (DSS), and colitis mother (animals born from mothers with induced colitis). Induction with DSS was performed 6 days before the tests, which occurred in the period between 60 and 90 days of life of the subjects. After induction, the electrophysiological responses were collected using the full field electroretinogram as an electrophysiological measure. Scotopic responses (rods, mixed 1 and mixed 2) and photoptic responses (from cones 1 Hz, S cones and flicker at 12, 18, 24 and 30 Hz) were measured. In addition, behavioral tests were performed by training with drinking fountain and evaluation of the perception of contrast, through stimulation with sinusoidal grids, arranged in different

frequencies. Statistical analysis was performed with one-way ANOVA test, using Tukey post- test, considering (P <0.05) as significant. It was found a reduction in the response amplitudes

in microvolts (μV) at 60 days in the following responses: b-wave of mixed 1 (colitis: 28.12 and ± 7.96, mother colitis 42.180 And ± 8,525), cone wave 1 Hz (colitis 39.85 and ± 12.74); Cones S (colitis 36.64 and ± 9.09 μV); 18 Hz Flicker (colitis: 25.12 ± 5.62, mother colitis: 38.37 ± 7.1); 24 hr (colitis: 22.46 ± 8.38, mother colitis: 29.41 ± 9.676) and 30 Hz (colitis: 14.4 ± 3.25, mother colitis: 27.13 ± 5.51). At 90 days, reduction in the b wave of rods (colitis: 57.06 ± 6.7), mixed 1 (colitis: 45.69 ± 7.86 and mother colitis: 56.03 ± 17.130), wave ‘a’ of photopic responses (Colitis, 25.1 ± 5.11) and cones S (colitis 31.04 ± 4.83), Flicker 18 Hz (colitis 29.1 ± 9.01) and Flicker 30 Hz (colitis: 41, 8 ± 5.09, mother colitis: 32.72 ± 11.4). There was an increase in implicit time in miliseconds (ms) in rods (colitis 24.68 ± 3.48 ms) and Flicker response of 12 Hz (colitis: 21.69 ± 4.65, mother colitis 22.14 ± 4.42) At 60 days. E cone S (colitis 13.35 ± 1.18) and Flicker 24Hz (mother colitis 28.4 ± 3.87) at 90 days. The behavioral tests showed a decrease in the responses of the colitis group and a delay in the learning on bar pressure response in comparison to the control group. Therefore, anemia impairs scotopic and photopic visual function, affecting rodent retinal cells with anemia and maternal anemia, as well entails in difficulties performing a behavioral learning task in the training performed at the operant conditioning box.