摘要目的 探讨干扰素γ(IFN-γ)在小鼠再感染呼吸道合胞病毒(RSV)中的作用.方法实验采用6~8周龄雌性野生型C57BL/6小鼠及IFN-γ敲除(IFN-γ-/-)小鼠,两种小鼠各自按随机数字表随机分为对照组和RSV组,每组再分为初次感染组和再次感染组;共8组.于处理小鼠后第5、7、14天收集标本,每组各时间点5~8只小鼠,实验重复2次.脱颈处死小鼠后灌取支气管肺泡灌洗液(BALF)并行炎症细胞计数;部分小鼠取左肺,HE染色后行组织病理评分;酶联免疫吸附试验(ELISA)检测BALF中的IFN-γ、白细胞介素(IL)-5、IL-13.组间比较采用t检验或单因素方差分析.结果(1)小鼠感染RSV后毛色变暗、体重减轻、活动及进食减少.(2)野生型小鼠初次及再感染RSV后第5、7天,BALF中IFN-γ均显著高于相应对照组[第5天(192±44)比(36±8)、(531±161)比(23±4)pg/ml,第7天(100±23)比(36±8)、(862±186)比(23±4)pg/ml,t=2.654、2.513、2.654、3.968,P均<0.05].(3)野生型小鼠再感染后体重下降程度较IFN-γ-/-小鼠轻[第5天(13.6±2.6)%比(22.7±2.9)%、第7天(18.0±3.1)%比(26.5±1.8)%,t=2.314、2.308,P均<0.05];肺组织病理评分较IFN-γ-/-小鼠低[第5天(1.50±0.09)比(2.07±0.11)分、第7天(1.53±0.11)比(2.08±0.09)分、第14天(1.10±0.06)比(1.59±0.08)分,t=3.916、3.890、4.837,P均<0.01];BALF中炎症细胞总数较IFN-γ-/-小鼠低[第5天(11.6±2.0)比(44.2±10.6)×105/ml、第7天(18.2±3.9)比(38.3±2.2)×105/ml,t=2.818、4.786,P均<0.05];Th2类细胞因子(IL-5、IL-13)水平也较IFN-γ-/-小鼠低[第5天(24±3)比(148±23)、(23±4)比(169±26)pg/ml、第7天(30±8)比(233±44)、(20±5)比(182±19)pg/ml、第14天(91±6)比(129±19)、(62±8)比(132±5)pg/ml,t=5.252、5.445、4.517、7.326、3.816、7.577,P均<0.01].结论IFN-γ可减轻小鼠再感染RSV后的气道炎症.

abstractsObjective To identify the role of interferon ( IFN)-γduring respiratory syncytial virus (RSV) re-infection in mice.Method Female wild type C57BL/6 mice and IFN-γknockout mice ( IFN-γ-/-mice) at the age of 6 to 8 weeks were randomly divided into two groups:control group and RSV group , according to random number table .Each group was further divided into primary infection group and re-infection group.There were 8 groups.Mice were sacrificed on days 5, 7, 14 to collect samples.There were 5 -8 mice in each group at each time point .And experiment was repeated twice . Leukocytes in bronchoalveolar lavage fluid ( BALF ) were counted , left lung tissues were stained with HE and histopathological scoring (HPS) was performed.The concentrations of IFN-γ, IL-5, IL-13 were determined with ELISA.T test or single factor analysis of variance was used to compare between groups .Result ( 1 ) Mice infected or reinfected with RSV showed pale hair , weight loss, decreased activity and anorexia.(2) IFN-γlevels significantly increased on days 5 and 7 following RSV primary infection and reinfection as compared to control groups in wild type mice ( ( 192 ±44 ) vs.( 36 ±8 ) and ( 531 ±161 ) vs.( 23 ±4 ) pg/ml on day 5, (100 ±23) vs.(36 ±8) and (862 ±186) vs.(23 ±4) pg/ml on day 7, t =2.654, 2.513, 2.654,3.968, all P<0.05).(3) Compared to the RSV-reinfected IFN-γ-/-mice, RSV-reinfected wild type mice had less body weight loss ((13.6 ±2.6)% vs.(22.7 ±2.9)%on day 5, (18.0 ±3.1)%vs.(26.5 ±1.8)%on day 7, t=2.314, 2.308, both P<0.05), lower lung tissue histopathological score ((1.50 ±0.09) vs.(2.07 ±0.11) on day 5, (1.53 ±0.11) vs.(2.08 ±0.09) on day 7, (1.10 ±0.06) vs.(1.59 ±0.08) on day 14, t=3.916, 3.890, 4.837, all P<0.01), less BALF inflammatory cells count ((11.6 ±2.0) vs.(44.2 ±10.6) ×105/ml on day 5, (18.2 ±3.9) vs.(38.3 ±2.2) ×105/ml on day 7, t=2.818, 4.786, both P<0.05), and lower levels of IL-5 and IL-13 ((24 ±3) vs.(148 ±23), (23 ±4) vs.(169 ±26) pg/ml on day 5, (30 ±8) vs.(233 ±44), (20 ±5) vs.(182 ±19) pg/ml on day 7, (91 ±6) vs.(129 ±19), (62 ±8) vs.(132 ±5) pg/ml on day 14, t=5.252, 5.445, 4.517, 7.326, 3.816, 7.577, all P <0.01 ) .Conclusion IFN-γcan alleviate airway inflammation following RSV reinfection in mice.