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Objective To explore the mechanisms of mesenchymal stem cells (MSC) in the treatment of concanavalin A (ConA)-induced acute immune liver injury in mice.Methods MSC were isolated and cultured from bone of the four limbs of three-week-old C57BL/6 mice.The specific surface markers were identified and osteogenic,adipogenic differentiation ability were tested.A total of 15 six to seven-week old C57BL/6 mice were divided into control group,MSC treatment group and phosphate buffer saline (PBS) treatment group,five mice in each group.The mice of MSC treatment group was injected through tail firstly with ConA and then MSC,PBS treatment group was injected through tail firstly with ConA and then PBS,control group was injected through tail with PBS twice.The mice were sacrificed in 14 to 16 hours after injection.The level of alanine aminotransferase (ALT),aspartate transaminase (AST) in peripheral blood were detected and the pathological change in liver tissue was scored by Knodell score system.Activation rate of splenic CD4+ T cells and the proportion changes of T hepler cell (Th)1,Th2,Th17 and regulatory T cells (Treg) were detected by flow cytometry and the ratio of Th17/Treg was calculated.The levels of tumor necrosis factor α (TNF-α),interferon (IFN)-γ and interleukin (IL)-4 in peripheral blood were detected by enzyme linked immunosorbent assay (ELISA).Independent-sample t test was used for comparison between groups of measurement data.Results ALT,AST and Knodell score of MSC treatment group was (174.2± 46.9) U/L,(185.6± 71.6) U/L and 3.4±1.3,respectively,which were better than those of PBS treatment group ((647.0± 118.0) U/L,(749.0± 104.0) U/L and 5.2 ±0.8,respectively),and the differences were statically significant (t =8.33,9.98 and 2.55,all P＜0.05).The activation rate of splenic CD4+ T cell of PBS treatment group was (26.10±2.17) ％,the proportion of Th1 and Th2 in CD4+ T cell was (5.81±0.79) ％ and (5.98± 1.22)％,the ratio of Th17/Treg was 0.29±0.03,the levels of TNF-α,IFN-γ and IL4 in peripheral blood were (1 281.95±88.61) U/L,(1 838.66±196.91) U/L and (1 192.36±163.94) U/L,which were higher than those of control group ((13.74±1.59)％,(1.35±0.17)％,(2.13±0.17)％,0.15± 0.05,(21.71±2.50) U/L,(11.84±1.28) U/L and (24.46±3.96) U/L),and the differences were statistically significant (t=10.26,12.37,7.02,5.30,31.79,15.93 and 20.75,all P＜0.01).There was no statistically significant difference in the activation rate of splenic CD4+T cell between MSC treatment group and PBS treatment group ((26.20±3.09)％ vs (26.10±2.17)％,P＞0.05).However,in MSC treatment group,the proportion of Th1 and Th2 in CD4+ T cell ((1.83±0.52) ％ and (2.75±1.06％)),the ratio of Th17/Treg (0.18±0.02) and the levels of TNF-α,IFN-γ and IL-4 in peripheral blood ((760.71± 73.19) U/L,(742.49±76.46) U/L and (825.76±101.74) U/L) significantly decreased compared with those of PBS treatment group,and the differences were statistically significant (t=9.45,4.48,6.41,10.14,5.56 and 10.22,all P＜0.01).There was no significant difference in the ratio of Th17/Treg between MSC treatment group and control group (P＞0.05).Conclusions The therapeutic effects of MSC on ConA induced acute immune liver injury were through influence splenic CD4+ T cell subsets by decreasing the proportion of Th1 and Th2 and then declining the levels of secreted cytokines such as TNF,IFN-γ and IL-4 in peripheral blood,increasing the proportion of Treg and decreasing the proportion of Th17 and keeping the balance of Th17/Treg.
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Objective To compare the effectiveness and safety of different concentrations of elastin-like polypeptides (ELP) as novel submucosal injection material for endoscopic submucosal dissection.Methods Forty healthy New Zealand white rabbits were randomly divided into two groups (n=20).The first group by submucosal injection of different drugs were randomly divide into five groups (n=4).Four concentrations of 50 ku ELP (0.05,0.025,0.012 5,0.005 g/ml) were used separately in each group,while glycerin fructose was used for control group.Each solution (2 ml) was injected into the submucosa through the resected margin,the increase of mucosal thickness and surface changes were observed and recorded at 0,5,10,and 30 min.The subgroup by submucosal injection of different drugs were randomly divide into five groups (n=4).The injection pressure of each solution (2 ml) with the 25-gauge needle was calculated by a manometer,which was connected between the needle and syringe.Results The submucosal uplift heights in groups using the 0.05 g/ml ELP and 0.025 g/ml ELP injection were significantly thicker than that of glycerin fructose (P＜0.05),the 0.012 5 g/ml ELP and glycerin fructose injection showed no significant difference (P＞0.05),whereas the uplift height in glycerin fructose group was thicker than that of the 0.005 g/ml ELP (P＜0.05).The injection pressure correlated with the ELP concentration.The injection pressures of 0.05,0.025,0.012 5,0.005 g/ml ELP solutions were (332±36) kPa,(223±24) kPa,(174±22) kPa and (142±19) kPa,respectively,and that of glycerin fructose was (269±17) kPa.The 0.025 g/ml ELP solution was easily injected into the porcine stomach to create submucosal uplift.The injection pressure of the 0.025 g/ml ELP solution showed significantly lower value compared with that of glycerin fructose (P＜0.05).Conclusions ELP might be a promising agent for submucosal injection for endoscopic submucosal dissection (ESD),and 0.025 g/ml ELP might be efficient concentration for maintaining mucosal elevation,injection pressure and safety.