Effects of granulocyte-macrophage colony stimulating factor on the repair of vessel intima damaged by balloon

The dysfunction of vascular endothelial cells plays a key role in startingand facilitating restenosis. The acceleration of intima repair and the recovery of endothelialfunction would reduce the restenosis rate. This study was undertaken to assess the effect ofgranulocyte-macrophage colony stimulating factor ( GM-CSF) on the repair of damaged iliac arteries.Twenty-four male New Zealand white rabbits undergoing primary iliac artery deendothelialization wererandomly divided into two groups ( GM-CSF group and control group) . The GM-CSF group received asubcutaneous injection of GM-CSF (10 μg ? kg^(-1) ? d^(-1) ) , and the control groupwas given a subcutaneous injection of equivalent saline. The iliac arteries of all animals weredamaged by balloon after 7 days. The levels of nitric oxide ( NO) were detected before, 1 week, 2weeks and 4 weeks after angioplasty. The repair and hyperplasia of the intima were observedmicroscopically and the indices of stenosis were evaluated by computerized planimetry after 4 weeksof angioplasty. The NO levels of the GM-CSF group were higher than those of the control group 2weeks and 4 weeks after angioplasty [91.92 +-11.57) μmol/L vs. (81. 67 +- 12. 18) μmol/L; (97. 67+- 10. 13 ) ( μmol/L vs. (83. 16 +-12. 64) μmol/L]. Four weeks after balloon damage,histological examination showed that neointima formation, vascular smooth muscle cells and fibroustissue of the GM-CSF group were less than those of the control group. The endothelium of the GM-CSFgroup was more integrated, and stenosis of lumen was slighter than that of the control group.Morphometry showed the lumen area of the GM-CSF group was larger than that of the control group[(1.27 +-0. 31) mm^2 vs. (0. 92 +- 0. 24) mm^2 ] , the neointimal area and percent of intimahyperplasia were significantly smaller than those of the control group [ (0. 85 +-0. 34) mm vs. (1.18 +-0. 38) mm^2; (40 +- 7)% vs. (55 +- 6)%]. GM-CSF could facilitate the repair of the intima,reduce neointima formation, better the function of the endothelium, and decrease the rate ofrestenosis.

EXPRESSION OF RHGM-CSF GENE IN EUKARYOCYTE BY LIPOFECTION

Objective: To recombinant the nearly natural human granulocyte-macrophage-colony stimulating factor (GM-CSF) for supplying more safe and steady expressed cytokine in clinic. Method: The eukaryotic recombinant pcDNA3.1-GM-CSF plasmid which was controlled by the CMV promoter was transferred into CHO cell by lipofectamine, selected by G418 and the positive clones was got. The recombinant vector which was rejoined into the groups of DNA of CHO was identified by PCR. Results: The results showed that the protein of rhGM-CSF was about 28 KD by using ELISA, SDS-PAGE and Western blot. Conclusion: rhGM-CSF was expressed steadily and highly. The rhGM-CSF will be of more use value.

Effect of cigarette smoke extract on lipopolysaccharide-activated mitogen-activated protein kinase signal transduction pathway in cultured cells

Background Lipopolysaccharide （LPS） forms outer membrane of the wall of Gram-negative cells. LPS can directly cause damage to epithelia of respiratory tract and is the major factor responsible for the chronic inflammation of respiratory passage. The mitogen-activated protein kinase （MAPK） signal transduction pathway of the airway epithelia is intimately associated with the action of LPS. The chronic inflammation of respiratory tract and smoking are interrelated and entwined in the development and progression of chronic lung diseases. This study was designed to examine the effects of cigarette smoke extract （CSE） and LPS on MAPK signal transduction pathway in order to further understand the roles CSE and LPS play in chronic lung inflammation. Methods Cultured primary human epithelial cells of airway were divided into four groups according to the stimulants used： blank control group, LPS-stimulation group, CSE-stimulation group and CSE plus LPS group. Western blotting was employed for the detection of phosphorylation level of extracellular-signal-regulated-kinase （ERK1/2）, p38 MAPK and c-Jun N-terminal kinase （JNK）. The expression of cytokines of MAPK transduction pathway （granulocyte-macrophage colony stimulating factor （GM-CSF） and mRNA of IL-8） in the primary epithelial cells of respiratory tract was also determined. Results Western blotting revealed that the phosphorylation levels of ERK1/2, p38 MAPK and JNK were low and 2 hours after the LPS stimulation, the phosphorylation of ERK1/2, p38 MAPK and JNK were all increased. There was a significant difference in the phosphorylation between the LPS-stimulation group and blank control group （P〈0.05）; no significant difference was found between CSE-stimulation group and blank control group （P〉0.05）; there was a significant difference between CSE ＋ LPS group and blank control group and between CSE ＋ LPS group and LPS group （P〈0.05）. The phosphorylation of CSE-LPS group was higher than that of blank control group but lower than that of LPS group. In blank control group, the expression of IL-8 and GM-CSF mRNA was low in the epithelial cells of airway and the release of IL-8 and GM-CSF was also at a low level. One hour after LPS stimulation, the level of IL-8 mRNA increased （P〈0.05） and reached a peak after 2 hours. On the other hand, GM-CSF mRNA level increased 2 hours after the stimulation （P〈0.05） and reached the highest level 4 hours after the stimulation. Two hours after LPS stimulation, IL-8 and GM-CSF protein level began to rise （P〈0.05）, and the level was the highest 8 hours after the stimulation （P〈0.01）. Stimulation with CSE alone had no effect on the release of IL-8 and GM-CSF and expression of IL-8 mRNA （P〉0.05）, but pre-treatment with CSE could delay the LPS-induced release of IL-8 and GM-CSF and the expression of IL-8 mRNA and its peak was lower. Conclusions LPS stimulation can significantly increase the phosphorylation of ERK1/2, p38 MAPK and JNK in the epithelial cells of airway and activate the MAPK transduction pathway, thereby can activate the downstream signal transduction pathway, and can ultimately result in the release of cytokines by the epithelial cells of airway. CSE can partially abolish the LPS-induced activation of MAPK signal transduction pathway and the expression of cytokines of the pathway, which might contribute to the development and progression of the inflammatory reactions in COPD patients.