Swank G M, Lu Q, Xu D Z, Michalsky M, Deitch E A
Department of Surgery, UMDNJ-New Jersey Medical School, Newark 07103, USA.
Crit Care Med. 1998 Jul;26(7):1213-7. doi: 10.1097/00003246-199807000-00023.
a) To determine if the sequence of exposure of intestinal epithelial cells to heat-shock or acute-phase stimuli would affect whether cellular protection or injury would occur; and b) to determine if the effects of a thermally induced heat-shock response can be mimicked by sodium arsenite, a nonthermal inducer of the heat-shock response.
In vitro controlled study.
Institutional laboratories.
Caco-2 human intestinal cell line.
Human intestinal epithelial cells (Caco-2) were grown on 35-mm culture dishes, chamber slides, or in a bicameral culture system to confluence or until tight-junction integrity was established. The cells were examined for viability, apoptosis, and bacterial translocation after exposure to a series of insults.
Control Caco-2 cells (medium only) and cells exposed to arsenite or to LPS alone had an apoptotic cell rate of 5.7%, 7.9%, and 8.6%, respectively. However, Caco-2 cells exposed to the cytokines IL-1beta and IL-6 had a significantly higher rate of apoptosis (22.1%, p < .01 vs. other groups). Caco-2 cells exposed to arsenite followed by LPS had 6.7% apoptotic cells, while cells exposed to LPS followed by arsenite had a significantly greater number of apoptotic cells (19.7%, p < .05). In addition, cells exposed to cytokines followed by arsenite had a higher apoptotic rate than cells exposed to arsenite followed by cytokines (28.4% vs. 10.6%, p < .01). Similar results were seen when cell viability was quantitated. At 3 hrs after challenge with Escherichia coli, the cytokine-exposed Caco-2 monolayers had a significantly increased rate of bacterial passage across the Caco-2 monolayer than control monolayers (p < .05), while the Caco-2 monolayers exposed to arsenite followed by cytokines or arsenite alone had a decreased rate of bacterial passage (p < .05). Conversely, cells exposed to cytokines or LPS before arsenite had the highest number of bacteria crossing the monolayer (p < .05).
These results indicate that preinduction of a heat-shock response (arsenite) can protect against cytokine or LPS-induced apoptosis and enterocyte dysfunction, as manifested by the passage of E. coli across an intact enterocyte monolayer. In contrast, the induction of a heat-shock response after exposure to acute-phase response inducers (cytokines and LPS) may result in decreased enterocyte viability, increased apoptosis, and cellular dysfunction.
a）确定肠道上皮细胞暴露于热休克或急性期刺激的顺序是否会影响细胞保护或损伤的发生；b）确定热诱导的热休克反应的效应是否可被亚砷酸钠模拟，亚砷酸钠是热休克反应的非热诱导剂。
体外对照研究。
机构实验室。
Caco-2人肠道细胞系。
人肠道上皮细胞（Caco-2）在35毫米培养皿、培养腔玻片或双室培养系统中生长至汇合或直至紧密连接完整性建立。在暴露于一系列损伤后，检测细胞的活力、凋亡和细菌移位情况。
对照Caco-2细胞（仅培养基）以及单独暴露于亚砷酸钠或脂多糖的细胞，凋亡细胞率分别为5.7%、7.9%和8.6%。然而，暴露于细胞因子白细胞介素-1β和白细胞介素-6的Caco-2细胞凋亡率显著更高（22.1%，与其他组相比p <.01）。先暴露于亚砷酸钠再暴露于脂多糖的Caco-2细胞有6.7%的凋亡细胞，而先暴露于脂多糖再暴露于亚砷酸钠的细胞凋亡细胞数量显著更多（19.7%，p <.05）。此外，先暴露于细胞因子再暴露于亚砷酸钠的细胞凋亡率高于先暴露于亚砷酸钠再暴露于细胞因子（28.4%对10.6%，p <.01）。在定量细胞活力时也观察到类似结果。在用大肠杆菌攻击3小时后，暴露于细胞因子的Caco-2单层细胞中细菌穿过Caco-2单层的速率比对照单层显著增加（p <.05），而先暴露于亚砷酸钠再暴露于细胞因子或仅暴露于亚砷酸钠的Caco-2单层细胞细菌穿过速率降低（p <.05）。相反，在亚砷酸钠之前暴露于细胞因子或脂多糖的细胞中穿过单层的细菌数量最多（p <.05）。
这些结果表明，热休克反应（亚砷酸钠）的预诱导可保护细胞免受细胞因子或脂多糖诱导的凋亡和肠上皮细胞功能障碍，这表现为大肠杆菌穿过完整的肠上皮细胞单层。相反，在暴露于急性期反应诱导剂（细胞因子和脂多糖）后诱导热休克反应可能导致肠上皮细胞活力降低、凋亡增加和细胞功能障碍。
