Changes of rabbit IL-1 and TNF-alpha, etc cytokines in response to acute normovolemic hemodilution with HAES-balanced solution as diluting agent / 中国应用生理学杂志

<p><b>AIM</b>To observe effect of acute normovolemic hemodilution(ANH) with HAES-balanced solution as diluting agent on levels of cytokines including IL-1, IL-2, IL-6 and TNF-alpha in rabbit serum so as to provide theoretical basis for clinical application.</p><p><b>METHODS</b>A total of 20 healthy adult rabbits were enrolled in the study and randomly divided into two groups (10 rabbits per group), i.e., control group (Group C) and HAES group (Group H). Under anesthesia of the rabbits, we performed incision of trachea, high-frequency jet ventilation and liberation of femoral artery and femoral veins. Group C was free from hemodilution. Group H was injected with dilution (2-fold of blood letting volume) via femoral veins during blood letting of the femoral artery. 6% HAES-steril plus compound solution of sodium lactate, with crystal/gel ratio of 2:1, blood letting volume = TBV x (Ho-Hf)/Hav. All blood was transfused back 60-120 min after blood letting. Venous blood was collected before blood letting (T0) and 30 min (T1), 60 min (T2), 120 min (T3) and 24 h(T4) after blood letting to detect Hb and Hct and measure level of IL-1, IL-2, IL-6 and TNF-alpha in serum.</p><p><b>RESULTS</b>In Group H, levels of IL-1, IL-2, IL-6 and TNF-alpha in serum were increased from T1 after ANH, reached peak at T3 but showed decrease at T4, with significant difference compared with Group C at T1, T2, T3 and T4 (P < 0.01) and significant difference compared with those before ANH (P <0.01). In Group C, there was no significant difference upon IL-1, IL-2, IL-6 and TNF-alpha in serum at different time points.</p><p><b>CONCLUSION</b>ANH with HAES-balanced solution as diluting agent can up-regulate the levels of cytokines IL-1, IL-2, IL-6 and TNF-alpha in rabbit serum. In the meantime, ANH may arouse eustress with low intensity and short action time, which exerts effect of enhancing immune function of the organisms.</p>

Dysfunction of endothelial NO system originated from homocysteine-induced aberrant methylation pattern in promoter region of DDAH2 gene / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Hyperhomocysteinemia (HHcy)-mediated dysfunction of endothelial NO system is an important mechanism for atherosclerotic pathogenesis. Dimethylarginine dimethylaminohydrolase (DDAH) is the key enzyme for degrading asymmetric dimethylarginine (ADMA), which is an endogenous inhibitor of endothelial nitric oxide (NO) synthase (eNOS). This study was designed to investigate whether the dysfunction of endothelial NO system originates from HHcy-mediated aberrant methylation modification in promotor region of DDAH2 gene.</p><p><b>METHODS</b>Human umbilical vein endothelial cells (HUVECs) were cultured to the third generation and treated with homocysteine (Hcy) at different concentrations (0, 10, 30, 100, and 300 micromol/L) for 72 hours. The methylation pattern in promoter region CpG island of DDAH2 gene was analyzed by nested methylation-specific PCR (nMSP). The mRNA expression of eNOS gene and DDAH2 gene was detected by semi-quantitative RT-PCR. The activity of DDAH2 and eNOS in cells, and the concentrations of ADMA and NO in culture medium were assayed respectively.</p><p><b>RESULTS</b>Mild increased concentration of Hcy (10 and 30 micromol/L) induced hypomethylation, while high concentration of Hcy (100 and 300 micromol/L) induced hypermethylation in the promoter CpG island of DDAH2 gene. The mRNA expression of DDAH2 increased in mild enhanced concentration of Hcy, and decreased in high concentration of Hcy correspondingly. The inhibition of DDAH2 activity, the increase of ADMA concentration, the reduction of eNOS activity and the decrease of NO production were all consistently relevant to the alteration of Hcy concentration.</p><p><b>CONCLUSION</b>The increased concentration of Hcy induced aberrant methylation pattern in promotor region of DDAH2 gene and the successive alterations in DDAH/ADMA/NOS/NO pathway, which showed highly relevant and dose-effect relationship. The results suggested that the dysfunction of endothelial NO system induced by HHcy could be partially originated from Hcy-mediated aberrant methylation in DDAH2 gene.</p>