Iodoacetic acid(IAA) has been applied to different species to acutely induce photoreceptor degeneration.The purpose of the present study was to use this toxin to thoroughly eliminate photoreceptors and induce complete blindness in the cat.IAA was delivered by single ear vein injection(20 mgkg-1).Six months after the IAA treatment,functional evaluations including pupillary light reflex(PLR),electroretinogram(ERG),visual behavior tests were performed.Morphological examinations were carried out after the functional evaluation.The present result shows that,six months after the IAA application,animals lost visual functions and became completely blind.High dose IAA application via ear vein delivery created an acute and reliable complete photoreceptor degeneration model in the cat.This model can be applied to genetic and cellular therapies for visual function restoration.
NAN YanZHANG QinREN ChaoRanHUANG XinGAO JieLI XiaoXinPU MingLiang
In this study, the role of melanopsin-expressing retinal ganglion cells （mRGCs） in the glaucoma-induced depressive behavioral response pattern was investigated. The CFP-D2 transgenic glaucoma animal model from five age groups was used in this study. Immunohistochemical labeling, quantitative analysis of mRGC morphology, open field test （OFT）, and statistical analysis were used. In comparison with C57 BL/6 mice, the age-matched CFP-D2 mice had significantly elevated intraocular pressure （lOP）. We observed parallel morphological changes in the retina, including a reduction in the density of cyan fluorescent protein- （CFP） expressing cells （cells mm^-2 at 2 months of age, 1309±26; 14 months, 878±30, P〈0.001）, mRGCs （2 months, 48_＋3; 14 months, 19±4, P〈0.001）, Brn3b-expressing RGCs （2 months, 1283±80; 14 months, 950±31, P〈0.001）, Brn-3b expressing mRGCs （5 months, 50.17%±5.5%; 14 months, 12.61%±3.8%, P〈0.001）, and reduction in the dendritic field size of mRGCs （mm^2 at 2 months, 0.077±0.015; 14 months, 0.065±0.015, P〈0.05）. CFP-D2 mice had hyperactive locomotor activity patterns based on OFT findings of the total distance traveled, number of entries into the center, and time spent in the center of the testing apparatus. The glaucoma induced hyperactive response pattern could be associated with dysfunctional mRGCs, most likely Brn-3b-positive mRGCs in CFP-D2 mice.
ZHANG QiVUONG HelenHUANG XinWANG YanLingBRECHA Nicholas C.PU MingLiangGAO Jie
