CD14和Toll样受体4的表达在内毒素致肝炎重型化中的意义

目的 探讨CD14和Toll样受体4(TLR4)在内毒素(LPS)诱导机体炎性因子分泌过程中的作用,阐明乙型肝炎重型化的机制. 方法 采用流式细胞学方法和逆转录聚合酶链反应等技术,检测30例慢性重型乙型肝炎患者,30例慢性乙型肝炎患者和20名健康者(对照组)的外周血单核细胞的mCD14水平及CD14 mRNA,TLR4 mRNA表达水平,同时应用动态浊度法测定患者血浆LPS水平,应用酶联免疫吸附法检测患者血清肿瘤坏死因子(TNF)α、白细胞介素(IL)-1 β,IL-6的含量.数据的统计分析采用SPSS11.5统计软件完成,分别采用单因素方差分析、非参数检验、Nemenyi法和直线相关分析.结果 外周血单个核细胞mCD14表达水平:慢性重型乙型肝炎组为74.2%±12.3%,慢性乙型肝炎组为63.6%±11.8%,对照组为60.3%±7.20/;CD14mRNA和TLR4 mRNA的相对表达:慢性重型乙型肝炎组分别为2.92±0.67和1.86±0.45,慢性乙型肝炎组分别为1.34±0.51和0.93±0.18,对照组分别为0.92±0.58和0.73±0.16,慢性重型乙型肝炎组均明显高于慢性乙型肝炎组和对照组,F值分别为11.473、85.037和102.328,P值均<0.01,差异有统计学意义.血浆LPS、IL-l,IL-6水平:慢性重型乙型肝炎组分别为(1.87±1.61)Eu/ml,(0.96±0.16)pg/ml和(68.34±48.30)pg/ml,慢性乙型肝炎组分别为(0.11±0.11)Eu/ml、(0.19±0.02)pg/ml,(19.28±4.65)pg/ml,对照组分别为(0.03±0.03)Eu/ml、(0.15±0.01)pg/ml、(12.01±3.88)pg/ml,慢性重型乙型肝炎组均明显高于慢性乙型肝炎组和对照组,χ2值分别为32.065、83.472、36.236,P值均<0.01.外周血TNFα表达水平:慢性重型乙型肝炎组为(19.78±9.25)pg/ml、慢性乙型肝炎组分别为(7.26±6.52)pg/ml、对照组分别为(4.15±4.06)pg/ml、F=35.092,P<0.01.相关分析显示,在慢性重型乙型肝炎组LPS水平与mCD14、CD14:mRNA,TLR4 mRNA表达水平呈明显的相关性,n=0.865、r2=0.415、r3=0.524,P值均<0.05.结论 LPS可能通过以CD14和TLR4为主的LPS受体激活及其信号传导,刺激炎性因子分泌的途径,在肝炎重型化过程中发挥重要作用.

The significance of CD14 and TLR4 expressions in severe hepatitis B induced by endotoxin

Objective To explore the roles of CD14 and TLR4 in severe hepatitis B induced by endotoxin. Methods The levels of mCD14 on PBMCs from 30 cases of severe hepatitis B, 20 cases of chronic hepatitis B and 20 cases of healthy controls were detected by flow cytometry. The expressions of CD14 mRNA and TLR4 mRNA in PBMCs from these patients were also detected by RT-PCR. Meanwhile, the concentration of plasma endotoxin was detected by limulus amebocyte lysate test and the levels of TNFα, IL-1, IL-6 in serum were detected by ELISA. Results The levels of mCD14 on PBMCs in severe hepatitis B, chronic hepatitis B and control were 74.2 ± 12.3,63.6 ± 11.8 and 60.3 ± 7.2 respectively. There was a significant difference among severe hepatitis B,chronic hepatitis B and healthy controls (both of P < 0.01). The expressions of CD14 mRNA and TLR4 mRNA (2.92 ± 0.67 and 1.86 ± 0.45) were also upregulated, compared with that in chronic hepatitis B patients (1.34 ± 0.51, 0.93 ±0.18) and healthy group (0.92 ± 0.58,0.73 ± 0.16) (P < 0.01). Similarly, the concentration of plasma endotoxin was much higher in severe hepatitis B (1.87 ± 1.61) than that in chronic hepatitis B patients (0.11 ±0.11) and that in healthy group (0.03 ± 0.03) (P < 0.01). As a result, the inflammation cytokines, shuch as TNF α, IL-1 and IL-6 (19.78 ± 9. 21,0.96 ± 0.16,68.34 ± 48.30) also increased significantly in severe hepatitis B, which were remarkably higher than those in chronic hepatitis B patients (7.26 ± 6.52,0.19 ± 0.02 and 19.28 ± 4.65) and healthy group (4.15 ± 4.06,0.15 ± 0.01 and 12.01 ± 3.88) (P< 0.01). Furthermore, correlation analysis showed there was positive correlation among the level of mCD14, the expression of CD14 mRNA/TLR4 mRNA, the concentration of endotoxin and the levels of inflammation cytokines in severe hepatitis B (r1 = 0.865, r2 = 0.415, r3 = 0.524, all of P < 0.05). Conclusion Endotoxin is an important factor in the aggravation of hepatitis B. Meanwhile, mCD14, CD14 mRNA and TLR4 mRNA are remarkably upregulated during the endotoxin stimulation. The inflammation cytokines (TNF α, IL-1 and IL-6) are also elevated, which may finally result in the aggravation of the hepatitis B. Therefore, CD14, TLR4 and inflammation cytokines play important roles in pathogenesis of severe hepatitis B induced by endotoxin.