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目的探讨BALB/c小鼠肝组织中NOD样受体蛋白3(NOD-like receptor protein 3,NLRP3)炎症小体活化与日本血吸虫(Schistosoma japonicum)感染所致肝纤维化程度的关系。方法 6~8周龄BALB/c雌性小鼠48只,分为未感染组(n=8)、感染后第5、6、8和12周组(n=10)。感染组每鼠经腹部皮肤贴片法感染日本血吸虫尾蚴(20±3)条。取小鼠肝脏组织,用天狼星红染色法检测肝组织切片中胶原的含量。抽提肝组织RNA,逆转录成cDNA,实时荧光定量PCR(qPCR)检测NLRP3、凋亡相关微粒样蛋白(apoptosis associated speck-like protein containing a CARD domain,ASC)、半胱天冬酶原1(pro-caspase-1)、白细胞介素-1β前体(proIL-1β)和IL-18前体(pro-IL-18)的RNA表达水平。用免疫组化染色结合H-score评分法检验小鼠肝脏半胱天冬酶1(caspase-1)p10和IL-1β的蛋白质表达水平。结果天狼星红染色结果显示,日本血吸虫感染后第5、6、8、12周小鼠肝脏切片的胶原面积百分比在第8周最高(29.66±1.07)%,其后依次为第6周(21.69±1.24)%、第12周(11.98±0.95)%和第5周(1.76±0.34)%。qPCR结果显示,与未感染组相比,感染后第5、6、8、12周小鼠肝脏NLPR3、ASC、pro-caspase-1、pro-IL-1β以及pro-IL-18的相对表达量为:NLRP3分别为8.12±0.66(P<0.01)、24.13±2.81(P<0.01)、14.86±0.35(P<0.01)、6.74±0.67(P<0.01),ASC为0.82±0.14、7.12±0.90、3.08±0.87、4.13±0.93(P<0.01),pro-caspase-1为1.14±0.72、2.53±0.46(P<0.05)、3.16±0.80(P<0.01)、2.19±0.87,pro-IL-1β为9.95±1.04、117.76±10.01(P<0.01)、36.98±11.73(P<0.01)、7.74±2.27,pro-IL-18为2.42±0.36、1.85±0.11、1.74±0.10、1.69±0.15。免疫组化结合H-score评分的结果显示,感染后第5、6、8和12周小鼠肝脏的caspase-1 p10和IL-1β的H-score值分别为2.80±0.12、2.10±0.06、8.57±1.00(P<0.01)、4.55±0.50(P<0.01)和0.13±0.13、0.20±0.00、3.30±0.59(P<0.01)、1.80±0.43。结论日本血吸虫感染小鼠的肝纤维化程度在第8周最明显,继而是第6周、第12周和第5周;NLRP3炎症小体在感染第6周、第8周显著活化;NLRP3炎症小体的活化与日本血吸虫感染所致的肝纤维化程度呈正相关。
Objective To investigate the relationship between the activation of NOD-like receptor protein 3 (NLRP3) inflammasome and the degree of hepatic fibrosis induced by Schistosoma japonicum in BALB / c mice. Methods 48 BALB / c female mice aged 6 to 8 weeks were divided into non-infected group (n = 8) and groups 5, 6, 8 and 12 weeks after infection (n = 10). Infection group, each mouse was infected with Schistosoma japonicum cercaria (20 ± 3) by abdominal skin patch method. The liver tissue of mice was taken and the content of collagen in liver slices was detected by Sirius red staining. The liver tissue RNA was extracted and reverse transcribed into cDNA. Real-time quantitative PCR (qPCR) was used to detect the expression of NLRP3, apoptosis associated speck-like protein containing a CARD domain (ASC) pro-caspase-1, pro-IL-1β and pro-IL-18. Immunohistochemical staining and H-score scoring were used to detect the protein expression levels of mouse liver caspase-1 p10 and IL-1β. Results The results of Sirius red staining showed that the collagen area percentage of liver slices at the 5th, 6th, 8th and 12th weeks after Schistosoma japonicum infection was the highest at the 8th week (29.66 ± 1.07)%, followed by the 6th week (21.69 ± 1.24%), 12 weeks (11.98 ± 0.95)% and 5 weeks (1.76 ± 0.34)%. qPCR results showed that the relative expression of NLPR3, ASC, pro-caspase-1, pro-IL-1β and pro-IL-18 in the liver of mice at 5, 6, 8 and 12 weeks after infection (P <0.01), NLRP3 were respectively 8.12 ± 0.66 (P <0.01), 24.13 ± 2.81 (P <0.01), 14.86 ± 0.35 (P <0.01) and 6.74 ± 0.67 , 3.08 ± 0.87, 4.13 ± 0.93 (P <0.01), pro-caspase-1 was 1.14 ± 0.72, 2.53 ± 0.46, 3.16 ± 0.80, 2.19 ± 0.87, 1β was 9.95 ± 1.04,117.76 ± 10.01 (P <0.01), 36.98 ± 11.73 (P <0.01), 7.74 ± 2.27, and pro-IL-18 was 2.42 ± 0.36,1.85 ± 0.11,1.74 ± 0.10,1.69 ± 0.15. The results of immunohistochemistry and H-score showed that the H-score of caspase-1 p10 and IL-1β in liver of mice at 2, 5, 6, 8 and 12 weeks after infection were 2.80 ± 0.12 and 2.10 ± 0.06, 8.57 ± 1.00 (P <0.01), 4.55 ± 0.50 (P <0.01) and 0.13 ± 0.13,0.20 ± 0.00,3.30 ± 0.59 (P <0.01), 1.80 ± 0.43 respectively. Conclusion The degree of hepatic fibrosis in mice infected with Schistosoma japonicum is the most obvious in the 8th week, followed by the 6th week, the 12th week and the 5th week. The NLRP3 inflammasome is significantly activated in the 6th week and the 8th week of infection. The NLRP3 inflammation Activation of the body is positively correlated with the degree of hepatic fibrosis induced by Schistosoma japonicum infection.