Yang Qian, Orman Mehmet A, Berthiaume Francois, Ierapetritou Marianthi G, Androulakis Ioannis P
Chemical and Biochemical Engineering Department, Rutgers, the State University of New Jersey, Piscataway, New Jersey 08854, USA.
J Surg Res. 2012 Aug;176(2):549-58. doi: 10.1016/j.jss.2011.09.052. Epub 2011 Oct 21.
Severe trauma, including burns, triggers a systemic response that significantly impacts on the liver, which plays a key role in the metabolic and immune responses aimed at restoring homeostasis. While many of these changes are likely regulated at the gene expression level, there is a need to better understand the dynamics and expression patterns of burn injury-induced genes in order to identify potential regulatory targets in the liver. Herein we characterized the response within the first 24 h in a standard animal model of burn injury using a time series of microarray gene expression data.
Rats were subjected to a full thickness dorsal scald burn injury covering 20% of their total body surface area while under general anesthesia. Animals were saline resuscitated and sacrificed at defined time points (0, 2, 4, 8, 16, and 24 h). Liver tissues were explanted and analyzed for their gene expression profiles using microarray technology. Sham controls consisted of animals handled similarly but not burned. After identifying differentially expressed probe sets between sham and burn conditions over time, the concatenated data sets corresponding to these differentially expressed probe sets in burn and sham groups were combined and analyzed using a "consensus clustering" approach.
The clustering method of expression data identified 621 burn-responsive probe sets in four different co-expressed clusters. Functional characterization revealed that these four clusters are mainly associated with pro-inflammatory response, anti-inflammatory response, lipid biosynthesis, and insulin-regulated metabolism. Cluster 1 pro-inflammatory response is rapidly up-regulated (within the first 2 h) following burn injury, while Cluster 2 anti-inflammatory response is activated later on (around 8 h post-burn). Cluster 3 lipid biosynthesis is down-regulated rapidly following burn, possibly indicating a shift in the utilization of energy sources to produce acute phase proteins, which serve the anti-inflammatory response. Cluster 4 insulin-regulated metabolism was down-regulated late in the observation window (around 16 h post-burn), which suggests a potential mechanism to explain the onset of hypermetabolism, a delayed but well-known response that is characteristic of severe burns and trauma with potential adverse outcome.
Simultaneous analysis and comparison of gene expression profiles for both burn and sham control groups provided a more accurate estimation of the activation time, expression patterns, and characteristics of a certain burn-induced response based on which the cause-effect relationships among responses were revealed.
严重创伤，包括烧伤，会引发全身反应，对肝脏产生重大影响，而肝脏在旨在恢复体内平衡的代谢和免疫反应中起关键作用。虽然其中许多变化可能在基因表达水平上受到调控，但为了确定肝脏中的潜在调控靶点，有必要更好地了解烧伤诱导基因的动态变化和表达模式。在此，我们使用微阵列基因表达数据的时间序列，在标准烧伤动物模型中对伤后24小时内的反应进行了特征描述。
大鼠在全身麻醉下接受占其全身表面积20%的全层背部烫伤。动物用生理盐水复苏，并在规定时间点（0、2、4、8、16和24小时）处死。取出肝脏组织，使用微阵列技术分析其基因表达谱。假手术对照组由处理方式相同但未烧伤的动物组成。在确定假手术组和烧伤组随时间差异表达的探针集后，将烧伤组和假手术组中与这些差异表达探针集对应的串联数据集合并，并使用“共识聚类”方法进行分析。
表达数据的聚类方法在四个不同的共表达簇中鉴定出621个烧伤反应性探针集。功能特征表明，这四个簇主要与促炎反应、抗炎反应、脂质生物合成和胰岛素调节的代谢有关。簇1促炎反应在烧伤后迅速上调（在最初2小时内），而簇2抗炎反应稍后被激活（烧伤后约8小时）。簇3脂质生物合成在烧伤后迅速下调，这可能表明能量来源的利用发生了转变，以产生急性期蛋白，用于抗炎反应。簇4胰岛素调节的代谢在观察窗口后期（烧伤后约16小时）下调，这提示了一种潜在机制来解释高代谢的发生，高代谢是严重烧伤和创伤的一种延迟但众所周知的反应，具有潜在的不良后果。
对烧伤组和假手术对照组的基因表达谱进行同步分析和比较，能够更准确地估计特定烧伤诱导反应的激活时间、表达模式和特征，并据此揭示反应之间的因果关系。
