Effect of dark rearing on development of visual sense and proteomics of visual cortex in growing rat / 中华实验眼科杂志

ABSTRACT

Background Previous study on critical period plasticity in local cortical circuits primarily was only to test the role of some proteins in visual cortex on visual development based on the existed neural signals expression system,but whole containing proteins analysis in cortical circuits is lack.To perform a whole containing proteins analysis has an important significance for critical period plasticity study.Objective This study was to investigate the influence of dark rearing on visual sense and proteomics in visual cortex for growing rat.Methods Two SD female rats were fed in two cages together with 12 newborn rats on the same day respectively,and half number of newborn rats were exchanged each other from first day after delivering and marked by eartipping.The newborn rats in a cage were bred in the dark environment for 40 days,and newborn rats in other cage were bred in the nature environment as controls.The blink response of rats to nearby object was examined and compared between the two groups of rats.Then three rats from two cages were sacrificed respectively and bilateral primary visual cortex tissue was isolated.Proteomics in rat primary visual cortex was detected by two-dimensional electrophoresis and mass spectrometry and the result was checked from database.Then the survival rats in the dark environment returned to the nature environment for 10 days,and the blink response of rats to nearby object were compared with that of agematched rats in the natural environment.The use and care of experimental rats followed the instruction of Ethic Committee of Nankai University.Results The blink response of rats was (0.33 ± 0.35) times in the dark environment for 40-day group,and that in the natural environment for 40-day group was (6.42±0.68) times,with a significant difference between them (t =24.38,P＜0.01).After returned to natural environment for 10 days,the blink response times of rats were less than those of the natural environment group ([5.00±1.22] times vs.[6.11±0.59]times),but this change was not statistically significant (t =2.09,P＞0.05).Two-dimensional electrophoresis and mass spectrometry assay revealed that 36 different proteins in visual cortex were found in the dark-feed rats compared with the natural environment rats,including 26 loss proteins and 10 extra proteins.Among the different proteins,Eps 15 homology domain-containing protein-3 (EHD3),tubulin alpha-1A chain and 2 ',3 '-cyclic-nucleotide 3 ' phosphordiesterase were the known proteins.Conclusions Dark rearing cause reversible visual loss in critical period plasticity newborn rat,and the change of proteomics in visual cortex is probably an affecting factor.