Sensory neurons with activated caspase-3 survive long-term experimental diabetes
Sensory neurons with activated caspase-3 survive long-term experimental diabetes
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DOI：
10.2337/diabetes.52.9.2363
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发表时间：
2003-09-01
期刊：
影响因子：
7.7
通讯作者：
Zochodne, DW
中科院分区：
文献类型：
--
作者：
Cheng, C;Zochodne, DW
长期实验糖尿病可能最好地模拟慢性人类糖尿病多发性神经病的突出和不可逆的感觉缺陷。虽然感觉神经元的不可挽回的损失，如果存在的话，将是该疾病的一个不幸的特征，系统的无偏计数表明，感觉神经元在长期的实验性糖尿病中存活下来。在这项研究中，我们研究了慢性实验性糖尿病的早期细胞凋亡是否仍在进行中，或者神经元是否以某种方式适应了它们的慢性损伤。采用转移酶介导dUTP镍端标记（TUNEL）、4′，6-二氨基-2-苯基吲哚（DAPI）染色和电镜观察细胞形态，观察长期实验链脲霉素诱导的糖尿病大鼠L4和L5背根神经节感觉神经元。没有证据表明细胞正在发生凋亡。尽管这证实了感觉神经元存活，但神经元在其细胞核、细胞质和近端轴突段中以独特的模式表达了活化的caspase-3。Bcl-2是抗凋亡信号的标志，在糖尿病和非糖尿病神经元中表达的数量相似。相比之下，糖尿病感觉神经元的细胞核、细胞质和近端轴突段DNA修复酶聚核糖聚合酶（PARP）的表达升高，但与caspase-3定位不重叠。糖尿病感觉神经元胞质中硝基酪氨酸的标记也明显增加，硝基酪氨酸是一种过氧亚硝酸盐毒性的标记物，据报道可以激活PARP。
Long-term experimental diabetes may best model the prominent and irreversible sensory deficits of chronic human diabetic polyneuropathy. Whereas irretrievable loss of sensory neurons, if present, would be an unfortunate feature of the disease, systematic unbiased counting has indicated that sensory neurons survive long-term experimental diabetes. In this study, we examined whether incipient cell loss from apoptosis in chronic experimental diabetes might nonetheless be in process, or whether neurons somehow adapt to their chronic insults. We examined sensory neurons in L4 and L5 dorsal root ganglia of long-term experimental streptozotocin-induced diabetic rats using transferase-mediated dUTP nick-end labeling (TUNEL), 4',6-diamidino-2-phenylindole (DAPI) staining of nuclear morphology, and electron microscopic appraisal of cell morphology. None provided any evidence for ongoing apoptosis. Despite this confirmation that sensory neurons survive, neurons had elevated expression of activated caspase-3 in unique patterns that included their nuclei, cytoplasm, and proximal axonal segments. Bcl-2 expression, a marker of antiapoptosis signaling, was observed in similar numbers of diabetic and nondiabetic neurons. In contrast, diabetic sensory neurons had elevated expression of the DNA repair enzyme poly(ADP-ribose) polymerase (PARP) in their nuclei, cytoplasm, and proximal axonal segments not overlapping with caspase-3 localization. Diabetic sensory neurons also had an apparent rise in cytoplasmic labeling of nitrotyrosine, a marker of peroxynitrite toxicity reported to activate PARP.