α-Crystallin protects RGC survival and inhibits microglial activation after optic nerve crush.
OBJECTIVE
Activation of retinal microglial cells (RMCs) is known to contribute to retinal ganglion cell (RGC) death after optic nerve injury. The purpose of this study was to investigate the effects of intravenous injection of α-crystallin on RGC survival and RMC activation in a rat model of optic nerve crush.


METHODS
RGCs were retrogradely labeled with fluorogold. Rats were intravenously injected with normal saline or α-crystallin (0.05g/kg, 0.5g/kg, and 5 g/kg) at 2, 4, 6, 8, 10, and 12 days after the optic nerve crush. Activated RMCs were characterized using immunofluorescence labeling with CD11b, and TNF-α and iNOS expression was detected using immunoblot analyses. We analyzed the morphology and numbers of RGC and RMC 2 and 4 weeks after injury using fluorescence and confocal microscopy.


RESULTS
The number of RGCs decreased after optic nerve injury, accompanied by significantly increased numbers of activated RMCs. Intravenous injection of α-crystallin decreased the number of RMCs, and enhanced the number of RGCs compared to saline injection. α-Crystallin administration inhibited TNF-α and iNOS protein expression induced by optic nerve injury.


CONCLUSIONS
Our results suggest that α-crystallin promotes RGC survival and inhibits RMC activation. Intravenous injection of α-crystallin could be a possible strategy for the treatment of optic nerve injury.
Department of Ophthalmology, Southwest Eye Hospital, Southwest Hospital, Third Military Medical University, Chongqing, 400038, China.
Nan
N
Wu
Department of Ophthalmology, Southwest Eye Hospital, Southwest Hospital, Third Military Medical University, Chongqing, 400038, China.
Jia
J
Yu
Department of Ophthalmology, Southwest Eye Hospital, Southwest Hospital, Third Military Medical University, Chongqing, 400038, China.
Shaojun
S
Chen
Department of Ophthalmology, Southwest Eye Hospital, Southwest Hospital, Third Military Medical University, Chongqing, 400038, China.
Jiangning
J
Xu
Department of Ophthalmology, Southwest Eye Hospital, Southwest Hospital, Third Military Medical University, Chongqing, 400038, China.
Xi
X
Ying
Department of Ophthalmology, Southwest Eye Hospital, Southwest Hospital, Third Military Medical University, Chongqing, 400038, China.
Mao
M
Ye
Department of Ophthalmology, Southwest Eye Hospital, Southwest Hospital, Third Military Medical University, Chongqing, 400038, China.
Yiru
Y
Li
Department of Ophthalmology, Southwest Eye Hospital, Southwest Hospital, Third Military Medical University, Chongqing, 400038, China. Electronic address: wangyieye@aliyun.com.
Yi
Y
Wang
D000818:Animals; D015153:Blotting, Western; D002470:Cell Survival / Q000187:drug effects; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D005260:Female; D005455:Fluorescent Antibody Technique; D007275:Injections, Intravenous; D008297:Male; D017628:Microglia / Q000187:drug effects* / Q000378:metabolism; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D009409:Nerve Crush; D052247:Nitric Oxide Synthase Type II / Q000235:genetics; D020221:Optic Nerve Injuries / Q000188:drug therapy* / Q000473:pathology; D051381:Rats; D020318:Rats, Long-Evans; D012165:Retinal Ganglion Cells / Q000187:drug effects* / Q000378:metabolism; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics; D038201:alpha-Crystallins / Q000008:administration & dosage / Q000494:pharmacology*
D014409:Tumor Necrosis Factor-alpha; D038201:alpha-Crystallins; D052247:Nitric Oxide Synthase Type II
Crystallin; Optic nerve injury; Retinal ganglion cell; Retinal microglial activation