Bigger J E, Tanigawa M, Zhang M, Atherton S S
Department of Microbiology, The University of Texas Health Science Center at San Antonio, USA.
Invest Ophthalmol Vis Sci. 2000 Jul;41(8):2248-54.
To determine the role of apoptosis in prevention and/or exacerbation of retinal disease in a mouse model of cytomegalovirus retinitis.
Immunocompetent or T-cell- depleted BALB/c mice were injected with murine cytomegalovirus (MCMV) by supraciliary injection. On sequential days after infection, mice were killed, and eyes were harvested for cryosectioning or for DNA extraction. Ocular sections were stained with monoclonal antibodies specific for MCMV or for T cells or used in the TdT-dUTP terminal nick-end labeling (TUNEL) assay to detect apoptotic cells.
In immunocompetent BALB/c mice, TUNEL assays revealed that a large area of the retina was apoptotic in relation to the relatively small number of MCMV-infected cells that were observed in the subjacent choroid and/or retinal pigment epithelium. In infected eyes from T-cell- depleted mice, there were more TUNEL-positive cells, and the areas of apoptosis were more extensive than in immunocompetent mice. These observations correlated with the increased extent of MCMV infection that is observed in the eyes of T-cell- depleted mice. However, irrespective of immune status, TUNEL-positive apoptotic cells were present mainly in areas of the retina overlying areas of MCMV-infected choroid and/or retinal pigment epithelium. More intense DNA laddering, indicative of increased apoptosis, was observed in the posterior segments of the eyes of T-cell- depleted mice after supraciliary inoculation with murine cytomegalovirus compared with less intense DNA laddering in the posterior segments of eyes of immunocompetent MCMV-infected mice.
The ability of the mouse's immune system to control MCMV infections in some tissues depends on induction of apoptosis in virus-infected cells. However, in the retina, cells undergoing apoptosis were not virus-infected, a finding that suggests that apoptosis of uninfected retinal cells may play a role in the pathogenesis of MCMV retinitis.
在巨细胞病毒性视网膜炎小鼠模型中确定细胞凋亡在视网膜疾病预防和/或加重过程中的作用。
通过睫状体上注射法给免疫活性或T细胞耗竭的BALB/c小鼠注射鼠巨细胞病毒（MCMV）。在感染后的连续几天，处死小鼠，摘取眼球用于冷冻切片或DNA提取。眼组织切片用针对MCMV或T细胞的单克隆抗体染色，或用于TdT-dUTP末端脱氧核苷酸转移酶介导的缺口末端标记（TUNEL）法检测凋亡细胞。
在免疫活性BALB/c小鼠中，TUNEL检测显示，相对于在相邻脉络膜和/或视网膜色素上皮中观察到的相对较少数量的MCMV感染细胞，视网膜的大片区域发生凋亡。在T细胞耗竭小鼠的感染眼中，TUNEL阳性细胞更多，凋亡区域比免疫活性小鼠更广泛。这些观察结果与在T细胞耗竭小鼠眼中观察到的MCMV感染程度增加相关。然而，无论免疫状态如何，TUNEL阳性凋亡细胞主要存在于覆盖MCMV感染脉络膜和/或视网膜色素上皮区域的视网膜区域。与免疫活性MCMV感染小鼠眼后部较弱的DNA梯带相比，睫状体上接种鼠巨细胞病毒后，T细胞耗竭小鼠眼后部观察到更强烈的DNA梯带，表明凋亡增加。
小鼠免疫系统控制某些组织中MCMV感染的能力取决于病毒感染细胞中凋亡的诱导。然而，在视网膜中，发生凋亡的细胞未被病毒感染，这一发现表明未感染的视网膜细胞凋亡可能在MCMV视网膜炎的发病机制中起作用。
