Lung injury and inflammatory responses in a rabbit model of brain death

doi:10.3969/j.issn.2095-4344.0367

Abstract

Abstract:

BACKGROUND: The quality of organs from donation after brain death is essential for the success of transplantation. Studies on the mechanism and protection of organ injury induced by brain death will provide references for the reasonable application of donor organs.
OBJECTIVE: To investigate the changes in the liver morphology and inflammatory factors at different time points after brain death in rabbits, and to explore the mechanism of inflammatory factors in lung damage induced by brain death.
METHODS: Forty rabbits were randomized into two groups (n=20 per group): sham operation group (tracheal intubation, femoral artery intubation, and sphenotresia), brain death group (low intracranial pressure to establish a state of brain death). The mean arterial pressure and heart rate in the two groups were recorded at postoperative 2, 6, 8 hours; the pathological changes of lung were observed by hematoxylin-eosin staining. The expression levels of inflammatory factors in the lung tissues including heat shock protein 27, intercellular adhesion molecule-1 and nuclear factor-κB were tested by RT-PCR and immunohistochemistry. The serum levels of interleukin-1, -6, and -8 were detected by ELISA.
RESULTS AND CONCLUSION: There were no significant differences in the mean arterial pressure and heart rate at 2, 6 and 8 hours after brain death (P > 0.05). The serum levels of interleukin-1, -6, and -8 increased with time, and the differences were significant (P < 0.05). The mRNA level of heat shock protein 27 in the brain death group was significantly higher than that in the sham operation group (P < 0.05). Under light microscope, the alveolar cavity was intact at 2 hours after brain death, capillary hemorrhage, widened alveolar septum and inflammatory cell infiltration occurred at 6 hours after brain death, and inflammatory cells almost infiltrated the entire lung at 8 hours, which were consistent with the expression levels of inflammatory factors like intercellular adhesion molecule-1 and nuclear factor-κB in the brain death group. In summary, brain death can lead to lung damage, which gets worse with time, and the damage is related to the release of inflammatory factors. Moreover, the lung damage peaks at 8 hours after brain death.

中国组织工程研究杂志出版内容重点：组织构建；骨细胞；软骨细胞；细胞培养；成纤维细胞；血管内皮细胞；骨质疏松；组织工程

Key words: Brain Death, Lung Transplantation, NF-κappa B, HSP27 Heat-Shock Proteins, Interleukins, Tissue Engineering

CLC Number:

R318

Li Ling1, Xu Qian1, Wei Wan-hui1, Zhao Hui-jia1, Shi Yu-ying1, Liu Lu1, Wang Yan-feng1, Ye Qi-fa1, 2 . Lung injury and inflammatory responses in a rabbit model of brain death[J]. Chinese Journal of Tissue Engineering Research, 2018, 22(28): 4481-4486.

Figures/Tables 2

2.1 实验动物数量分析实验选用家兔40只，分为2组，均进入结果分析，无实验动物脱失。 2.2 脑死亡前及脑死亡2，6，8 h动脉血压和心率变化脑死亡组和假手术组动脉血压在颅内加压前差异无显著性意义(P > 0.05)。开始颅内加压时，脑死亡组动脉血压明显上升(P < 0.01，图1A)，峰值达400 mm Hg(1 mm Hg= 0.133 kPa)左右。停止加压后血压显著下降，用多巴胺 2 μg/(kg·min)静脉滴入维持在100 mm Hg左右。检测停止加压后2，6，8 h心率，脑死亡组各时间点心率的差异及与假手术组间心率的差异均无显著性意义(P > 0.05，图1B)。结果提示，在去神经支配的情况下给予多巴胺等升压药物和呼吸机辅助呼吸支持，生命体征相对稳定。 2.3 脑死亡状态下肺脏病理损伤光镜下(图2)：①脑死亡组：2 h肺泡腔完整，渗出物较少，间隔均匀，肺泡壁光滑，偶见中性粒细胞；6 h，肺泡间隔增宽并有水肿，炎症细胞浸润逐渐增多，肺泡腔有渗出液；8 h损伤最为严重，肺泡腔完整性丧失，视野中满布炎症细胞；②假手术组：与脑死亡组相比，各时间点肺脏损伤程度更轻，表现为肺间质水肿程度减轻，炎症细胞浸润减少，肺泡结构更完整。 2.4 血清白细胞介素1β、6、8水平 ELISA结果表明，脑死亡后6，8 h血清白细胞介素6和白细胞介素8水平均高于假手术组(P < 0.05)，8 h的脑死亡组和假手术组白细胞介素1β的差异有显著性意义(P < 0.05)。白细胞介素1β、6、8水平随着脑死亡时间延长有均上升趋势(图3，P < 0.05)。 2.5 HSP27 mRNA的表达 RT-PCR结果显示，与假手术组相比，脑死亡组各时间点HSP27 mRNA水平均明显升高(图4A，P < 0.05)，且HSP27 mRNA表达随脑死亡时间的延长呈上升趋势，其相对表达量从脑死亡后2 h的0.205± 0.023增加到脑死亡后6 h的0.778±0.055，差异有显著性意义(图4B，P < 0.05)。 2.6 细胞间黏附分子1和NF-κB的表达脑死亡后各时间点肺组织中细胞间黏附分子1和NF-κB蛋白质阳性的细胞比例较前一时间点均有明显差异(P < 0.05)，较假手术组对应时间点也都有升高(图5，6)。"

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