Differentially expressed genes analysis by cDNA microarray during liver regenration after partial hepatectomy and different stages of liver development in rats.

Liver transcriptome codes for diverse metabolic functions and involves several pathways. During different developmental stage of rat liver, differential expression of specific genes occur and allow the liver cells to enter into the further developmental stage. In regenerating rat liver, the mass of the lost liver is regained by a highly synchronized multi-step process involving expression of specific genes in a temporal manner. In our study, the transcriptional profile of developing liver (2wks and 4 wks), regenerating liver and adult liver based on microarray data has been systematically compared. Also the biological relevance of differentially expressed genes were also analysed through gene ontology (GO) and pathway analysis. Rat liver was excised out from the animals of different age groups (2 weeks, 4 weeks and 12 weeks) and partially hepatectomized rats at 8 h post surgery, for RNA extraction and hybridization on affymetrix microarray. Each sample was processed in duplicate and checked for quality of total RNA. The RNA was used as a starting template to synthesize double-stranded cDNA with random hexamers tagged with T7 promoter sequence. The fragmented DNA was labeled and used for overnight hybridization with Rat Gene ST 1.0 arrays, followed by washing, staining and scanning.

肝脏转录组（transcriptome）承担多种代谢功能，并参与多条信号通路。在大鼠肝脏的不同发育阶段，特异性基因会发生差异表达，推动肝细胞进入后续发育阶段。在再生大鼠肝脏中，丢失的肝组织通过高度同步化的多步骤过程实现体积恢复，该过程中特异性基因会按时间顺序动态表达。
本研究基于微阵列芯片（microarray）数据，对发育阶段肝脏（2周龄与4周龄）、再生肝脏及成年肝脏的转录谱进行了系统比较，并通过基因本体论（Gene Ontology，GO）和通路分析，解析了差异表达基因的生物学关联。
实验中，本研究从不同年龄组（2周、4周及12周）大鼠以及术后8小时的部分肝切除大鼠体内摘取肝脏，用于RNA提取并在Affymetrix微阵列芯片上完成杂交反应。每份样本均进行双份平行处理，并对总RNA质量进行检测。以该RNA为起始模板，利用带有T7启动子序列的随机六聚体引物合成双链互补DNA（cDNA）；将片段化的DNA进行标记后，与大鼠基因ST 1.0芯片进行过夜杂交，随后依次完成洗涤、染色与扫描操作。