Gastinger Matthew J, Singh Ravi S J, Barber Alistair J
Milton S. Hershey Medical Center, Penn State Retina Research Group, Ulrich Ophthalmology Research Laboratory, Pennsylvania State College of Medicine, Hershey, Pennsylvania 17033, USA.
Invest Ophthalmol Vis Sci. 2006 Jul;47(7):3143-50. doi: 10.1167/iovs.05-1376.
To identify amacrine cells that are vulnerable to degeneration during the early stages of diabetes.
Whole retinas from streptozotocin (STZ)-diabetic rats and Ins2(Akita) mice were fixed in paraformaldehyde. Apoptotic cells in the retina were quantified using terminal dUTP nick-end labeling (TUNEL) and active caspase-3 (CM-1) immunohistochemistry. Immunohistochemical markers for choline acetyltransferase (ChAT) and tyrosine hyroxylase (TH) were also used to quantify populations of amacrine cells in the Ins2Akita mouse retinas.
The number of TUNEL-positive nuclei increased from 29+/-4 in controls to 72+/-9 in the STZ-diabetic rat retinas after only 2 weeks of diabetes. In rats, CM-1-immunoreactive (IR) cells were found primarily in the inner nuclear and ganglion cell layers after 2, 8, and 16 weeks of diabetes. At each end point, the number of CM-1-IR cells in the retina was elevated by diabetes. Approximately 2% to 6% of the CM-1-IR cells in the inner nuclear layer (INL) were double-labeled for TH immunoreactivity. After 6 months of diabetes in the Ins2Akita mouse, the morphology of the labeled ChAT-IR and TH-IR amacrine cell somas and dendrites appeared normal. A quantitative analysis revealed a 20% decrease in the number of cholinergic and a 16% decrease in dopaminergic amacrine cells in the diabetic mouse retinas, compared with the nondiabetic control.
Dopaminergic and cholinergic amacrine cells are lost during the early stages of retinal neuropathy in diabetes. Loss of these neurons may play a critical role in the development of visual deficits in diabetes.
识别在糖尿病早期易发生变性的无长突细胞。
将链脲佐菌素（STZ）诱导的糖尿病大鼠和Ins2（Akita）小鼠的整个视网膜用多聚甲醛固定。使用末端脱氧核苷酸转移酶介导的缺口末端标记（TUNEL）和活性半胱天冬酶-3（CM-1）免疫组织化学对视网膜中的凋亡细胞进行定量。胆碱乙酰转移酶（ChAT）和酪氨酸羟化酶（TH）的免疫组织化学标记物也用于量化Ins2Akita小鼠视网膜中无长突细胞的数量。
糖尿病仅2周后，STZ诱导的糖尿病大鼠视网膜中TUNEL阳性细胞核的数量从对照组的29±4增加到72±9。在大鼠中，糖尿病2周、8周和16周后，CM-1免疫反应性（IR）细胞主要在内核层和神经节细胞层中被发现。在每个时间点，糖尿病均使视网膜中CM-1-IR细胞的数量增加。内核层（INL）中约2%至6%的CM-1-IR细胞对TH免疫反应性呈双重标记。Ins2Akita小鼠糖尿病6个月后，标记的ChAT-IR和TH-IR无长突细胞体和树突的形态看起来正常。定量分析显示，与非糖尿病对照组相比，糖尿病小鼠视网膜中胆碱能无长突细胞数量减少20%，多巴胺能无长突细胞数量减少16%。
糖尿病视网膜神经病变早期，多巴胺能和胆碱能无长突细胞丢失。这些神经元的丢失可能在糖尿病视觉缺陷的发展中起关键作用。
