可诱导共刺激分子及相关细胞因子在细粒棘球蚴感染小鼠免疫调控中的作用

目的 探讨可诱导共刺激分子(inducible costimulatory molecule,ICOS)及相关细胞因子在细粒棘球蚴感染小鼠免疫调控中的作用.方法 80只BALB/c小鼠(体质量18～ 22 g)随机分为对照组和感染组,每组40只.按10000个原头节/只腹腔注射制备细粒棘球蚴感染小鼠模型,腹腔接种2、8...

Role of inducible costimulatory molecules (ICOS) and related cytokines in immune regulation of Echinococcus granulosus infections in mice

Objective　To investigate the roles of inducible costimulatory molecules (ICOS) and related cytokines in the immune regulation of Echinococcus granulosus infections in mice. Methods　Eighty BALB/c mice (weight 18-22 g) were divided into the control and infection groups, of 40 animals in each group. E. granulosus infection was modeled in mice by intraperitoneal injection of 10 000 protoscoleces per mouse. Serum levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphatase (ALP) and peripheral interleukin⁃4 (IL⁃4) and IL⁃10 levels were measured 2, 8, 30, 60, 180 days post⁃infection. Mouse liver specimens were excised for hematoxylin⁃eosin (HE) staining and immunostaining, and ICOS expression was quantified in mouse liver specimens using quantitative real⁃time PCR (qPCR) assay. Results　There were no significant differences in serum ALT (F = 12.082, P < 0.05), AST (F = 6.347, P < 0.05) or ALP levels (F = 52.186, P < 0.05) in mice 2, 8, 30, 60 and 180 days post⁃infection with E. granulosus. The serum ALT levels were significantly higher in the infection group than in the control group 2 [(61.72 ± 9.89) vs. (50.65 ± 4.67) U/L, P < 0.05] and 30 days post⁃infection [(80.61 ± 23.71) vs. (67.75 ± 9.79) U/L, P < 0.05], and the serum ALT levels were significantly higher in the infection group than in the control group 2 [(181.06 ± 60.61) vs. (115.58 ± 17.66) U/L, P < 0.05] and 180 days post⁃infection [(137.84 ± 29.01) vs. (108.05 ± 10.33) U/L, P < 0.05], while greater serum ALP levels were measured in the infection group than in the control group 2 [(162.90 ± 21.04) vs. (64.54 ± 5.99) U/L, P < 0.05], 8 [(176.36 ± 24.56) vs. (62.70 ± 9.21) U/L, P < 0.05] and 30 days post⁃infection [(138.86 ± 13.59) vs. (58.60 ± 5.28) U/L, P < 0.05]. A few inflammatory cells were seen in mouse liver in the infection group 30 days post⁃infection, and no apparent changes were found in the mouse hepatic structure 60 days post⁃infection. On day 180 post⁃infection, a large number of epithelium⁃like cells presented fibrotic growth in mouse liver in the cyst⁃infiltrating regions, with cuticula formation seen, and plenty of red cells were present in lesions and hepatocyte space. Positive ICOS expression was detected in mouse liver in the infection group, with ICOS⁃positive cells predominantly seen in the cytoplasm of the hepatocyte, and the ICOS expression increased over time. The relative ICOS mRNA expression was 2.732 ± 0.094 on day 180 post⁃infection, which was significantly greater than that on day 2 post⁃infection (0.746 ± 0.049). There were no significant differences in serum IL⁃4 or IL⁃10 levels at different time points after E. granulosus infections, while the serum IL⁃4 and IL⁃10 levels peaked in the infection group180 days and 60 days post⁃infection, respectively. Higher serum IL⁃4 levels were measured in the infection group than in the control group 8 [(22.50 ± 3.24) vs. (5.82 ± 0.49) pg/mL, P < 0.05], 30 [(15.49 ± 4.73) vs. (5.10 ± 1.38) pg/mL, P < 0.05], 60 [(36.93 ± 6.14) vs. (4.13 ± 1.19) pg/mL, P < 0.05] and 180 days post⁃infection [(198.35 ± 0.70) vs. (4.19 ± 0.98) pg/mL, P < 0.05], and higher IL⁃10 levels were measured in the infection group than in the control group 2 [(4.84 ± 1.91) vs. (2.11 ± 1.03) pg/mL, P < 0.05], 8 [(44.72 ± 14.63) vs. (3.16 ± 0.60) pg/mL, P < 0.05], 30 [(25.47 ± 8.00) vs. (3.83 ± 1.87) pg/mL, P < 0.05], 60 [(187.16 ± 60.44) vs. (3.69 ± 1.05) pg/mL, P < 0.05] and 180 days post⁃infection [(85.40 ± 7.15) vs. (3.25 ± 0.93) pg/mL, P < 0.05]. Conclusions　High ICOS expression is present in the liver of mice with E. granulosus infections. The positive ICOS expression and immune activation levels increase with the time of E. granulosus infections, leading to aggravation of hepatocyte injury caused by inflammation.