髓系细胞触发受体-1在急性肺损伤小鼠肺组织中的表达

Expression of triggering receptor-1 on myeloid cells of mice with acute lung injury

目的 观察髓系细胞触发受体-1（TREM-1）在急性肺损伤（ALI）小鼠肺组织中的表达规律及其在肺部炎性反应中的意义.方法 30只BALB/C小鼠,按随机数字表法分为正常对照组（6只）与ALI组（24只）,ALI组脂多糖（LPS）腹腔注射（10 mg/kg）复制ALI模型,并分别于造模后6 h,12 h,24h和48 h留取外周血及肺组织,采用荧光实时定量逆转录多聚酶链反应（RT-PCR）法检测TREM-1mRNA,酶联免疫吸附法（ELISA）检测TREM-1和肿瘤坏死因子（TNF-α）以及HE染色光镜下进行肺Smith病理损伤评分.采用方差分析比较各组TREM-1 mRNA,TNF-α和Smith评分,Spearman相关性分析计算三者之间的关系.结果 ALI小鼠6 h,12 h,24 h和48 h肺组织TREM-1 mRNA的表达[（6.61±0.08）,（34.71±0.83）,（61.85±14.05）和（56.46±8.89）]高于正常对照组（1.00±0.00）（P=0.017,0.009,0.002,0.003）,血液TREM-1 mRNA的表达[（14.01±3.24）,（47.07±0.98）,（8.18±0.43）,（8.06±0.05）]也高于正常对照组（1.00±0.00）（P=0.010,0.004,0.011,0.011）;肺组织TREM-1 mRNA造模后6 h开始升高,24 h达到峰值;血液TREM-1 mRNA 12 h达到峰值.ALI小鼠6 h,12 h,24 h和48 h肺组织中TREM-1浓度[（997.8±114.62）,（1579.70±45.92）,（1123.9±108.2）,（429.8±89.96）pg/mL]均高于正常对照组（279.22±4.63 pg/mL）（P=0.024,0.007,0.011,0.04）,12 h达到峰值,但与TREM-1mRNA表达水平差异无统计学意义（P〉0.05）.ALI小鼠6 h,12 h,24 h和48 h肺组织TNF-α浓度[（313.16±39.50）,（491.91±96.65）,（388.48±29.84）,（282.5±52.76）pg/mL]显著高于正常对照组（256.6±28.31 pg/mL）,（P=0.037,0.019,0.032,0.043）,12 h达到峰值;且与肺组织TREM-1浓度及肺组织Smith病理评分呈正相关（r=0.795,P=0.001;r=0.499,P=0.034）,而与肺组织TREM-1mRNA表达无相关性（P=0.176）.结论 ALI时肺组织中TREM-1表达升高,与TNF-α水平及肺损伤程度相关,参与ALI肺部炎性反应,且TREM-1的基因表达与蛋白水平并不一致提示可能存在新的功能蛋白参与免疫调控.

Objective To observe the expression of triggering receptor-1 on myeloid cells （TREM-1） of mice with acute lung injury （ALI） in oder to find out its regularity and significance in inflammatory response of or-ganisms. Method Thirty BALB/C mice were randomly（random number） divided into normal control group （n =6） and ALl group （n = 24）. The models of ALI were made with intraperitonal injection of lipopolysaccharide （LPS） in dose of 10 mg/kg. Specimens from peripheral blood and lung tissue were collected 6 h, 12 h, 24 h and 48 h after LPS injected. The fluorescent real-time quantitative reverse transcriptiun-polymerase chain （RT-PCR） was used to detect TREM-1 mRNA, and ELISA was employed for detection of TREM-1 protein and TNF-α protein, and HE staining was made doe the pathological Smith lung score under light microscope. Analysis of variance was used for comparison of TREM-1 mRNA, TNF-α and Smith lung injury score between two groups. Spearman corre-lation analysis was made to find out the relationship among these three variables. Results The expressions of TREM-1 mRNA in lung tissue of ALI mice 6 h, 12 h, 24 h, and 48 hours after injection of LPS were 6.61±0.08,34.71±0.83, 61.85±14.05 and 56.46±8.89, respectively which were higher than that in control group （1.00±0.00, P = 0.017, 0.009, 0.002 and 0.003, respectively）. The expressions of TREM-1 mRNA in blood were 14.01±3.24, 47.07±0.98, 8.18±0.43 and 8.06±0.05, respectively which were higher than that in normal control group （1.00±0.00, P = 0.010, 0.004, 0.011 and 0.011, respectively）. The expression of TREM-1 rnRNA in tissue began to increase 6 hours after modeling and reached its peak 24 hours later, and expres-sion of TREM-1 mRNA in blood reached its peak after 12 hours. The levels of TREM-1 protein in lung tissue of ALl mice 6 h,12 h,24 h and 48 hours after LPS injected were 997.8±114.62, 1579.70±45.92, 1123.9±108.2 and 429.8±89.96 pg/mL, respectively which were higher than that of mice in control group （279.22±4.62 pg/mL, P = 0.024, 0.007, 0.011 and 0.04, respectively）. The level of TREM- 1 protein reached the peak 12 hours after LPS injected, but it had no significant correlation with the expression of TREM-1 mRNA （P =0.14）. The levels of TNF-α protein in lung tissue of ALI mice 6 h, 12 h, 24 h and 48 hours after LPS injection were 313.16±39.50, 491.91±96.65, 388.48±29.84 and 282.5±52.76 pg/mL, respectively which were sig-nificantly higher than that of mice in control group （256.6±28.31 pg,/mL, P = 0.037, 0.019, 0.032 and 0.043, respectively）. The TNF-α concentration was positively correlated with TREM-1 levels in lung tissue and with Smith pathological score （r = 0.795, P = 0.001： r = 0.499, P = 0.034）, but not with the expression of TREM-1 mRNA （P = 0.176）. Conclusions The expression of TREM-1 mRNA in lung tissue of mice with ALI is elevated, and the expression of TREM-1 mRNA is related to the level of TNF-α and the severity of the ALI in in-flammatory responses in lung. The expressions of TREM- 1 gene are not consistent with the levels of TREM- 1 pro-tein, suggesting another new functional proteins involved in immune regulation.