Objective To explore the mechanism of microRNA (miRNA, miR)-155 in the rejection after liver transplantation in rats. Methods The rats were divided into two groups. In the xenograft model group (rejection group, n=10),the donors were male Lewis rats and the recipients were male BN rats.In the allograft model group(control group, n=10),both the donors and recipients were male Lewis rats.The rat models with orthotopic liver transplantation were established by two-cuff technique in two groups. At postoperative 7 d, the animals were sacrificed for the collection of blood and liver tissue samples. The serum levels of alanine aminotransferase (ALT), total bilirubin (TB), and cytokines of interleukin (IL)-2, IL-4, interferon (IFN)-γ were quantitatively measured. The pathological changes of liver tissues were observed under light microscope. In each group, three liver tissue samples were prepared and subject to high-throughput sequencing. The miRNAs related to rejection were identified for bioinformatics analysis to predict and analyze relevant signaling pathways and genes. Results In the rejection group, the serum levels of ALT and TB were significantly higher than those in the control group (both P<0.01). Compared with the control group, the levels of IL-2 and IFN-γ were considerably up-regulated (both P<0.01), whereas the level of IL-4 was dramatically down-regulated (P<0.01). Pathological examination demonstrated that more evident rejections were observed in the rejection group than the control group. High-throughput sequencing revealed that the expression level of miR-155 was significantly up-regulated in the rejection group, which was 5.89 times of that in the control group. Bioinformatics analysis demonstrated that up-regulation of miR-155 was associated with the mammalian target of rapamycin (mTOR), mitogen-activated protein kinase (MAPK) and T cell receptor signaling pathways. The genes which were probably responsible for regulation included the yeast autophagy related gene 1(ATG1) and its homologous gene ULK2, insulin-like growth factor-1 (Igf-1) and G protein-coupled receptor regulatory gene(Arrb1),etc.Conclusions miR-155 might promote the incidence and progression of rejection after liver transplantation in rats. The involved signaling pathways probably include the mTOR, MAPK signaling pathway and T cell receptor signaling pathway.ATG1,ULK2,Igf-1,and Arrb1 genes may participate in this process.

Objective: To explore the positive rate of intrinsic factor antibody (IFAb) and level of vitamin B₁₂ (VitB₁₂) in normal physical examination population and the possible relation between IFAb, VitB12 and sex, age, number of RBC, HGB and MCV. Methods: A total of 1 427 people who came to Peking Union Medical Colleague Hospital (PUMCH) for physical examination were enrolled. There were 758 males with average age of (52.5±14.5) years-old and 669 females with average age of (50.3±14.3) year-old. Beckman DxI800 automatic biochemical-immune analyzer and corollary reagents were used to analyze the level of serum IFAb and VitB₁₂. The results in different sex, age were documented and their correlation with the value of whole blood cell count was tested later on. Results: Among the 1 427 normal subjects, 66 (4.63%) were positive for IFAb. The positive rate for IFAb in the population≥40 years-old was higher than those<40 years-old (5.66% vs 1.48%, χ²=7.46, P=0.006). The deficiency rate of VitB₁₂ in the population<40 years-old, 40-59 years-old and ≥60 years-old was 2.22%, 2.51% and 5.50%, respectively (χ²=8.55, P=0.014). There were no difference between people with different sex in the positive rate of IFAb (5.15% for males and 4.04% for females, χ²=0.99, P=0.320) or in the deficiency rate of VitB₁2 (3.83% for males and 2.69% for females, χ²=1.44, P=0.230). The results of multiple linear regression showed that HGB level of IFAb positive subjects was 3.05 g/L lower on average than those of IFAb negative, but IFAb had no effect on both RBC and MCV. There was no correlation between VitB₁2 deficiency and HGB, RBC and MCV. Conclusion The positive rate of IFAb and deficiency rate of VitB₁2 increase as age increases. But the presence of VitB₁₂ deficiency is later than the positive findings of IFAb. IFAb showed some effects on the level of HGB, which may compensate the limitations of VitB₁₂ detection to some extent. It is necessary to check the IFAb and level of VitB₁₂ in people with middle or old ages.