Objective To study the concentration of neurotrophins( including NGF, BDNF, NT3 and NT4) in the lung of SD rats infected by respiratory syncytial virus( RSV) , and to explore the relationship between the concentration of the neurotrophins, airway hyperresponsiveness and airway neural plasticity.Methods Twenty SD newborn rats were randomly divided into a control group and a RSV-infected group with ten rats in each group. The RSV-infected group were infected with 5 ×104 TCID50/0. 1 mL RSV each week. After 8 weeks, the bronchial responsiveness of the SD rats was assessed. The bronchial inflammation was assessed by HE staining with left lung. Synaptophysin and neurofilament expressions in the lung of SD rats were assayed by the immunohistochemistry staining. In situ hybridization was used to detect the RSV RNA in the lung. The concentration of neurotrophins in the lung of SD rats were detected by ELISA. Results The RSV-infected group showed elevated airway hyperresponsiveness and more inflammatory cells infiltrated in the lung; In situ hybridization showed positive signal of RSV RNA in lung interstitium of the RSV-infected rats. Synaptophysin and neurofilame levels in the airway were increased in the RSV-infected group. Supernatant levels of NGF and BDNF were significantly increased compared with the control group ( P lt;0. 05) . The NT3 and NT4 levels had no significant difference in all groups. The expressions of NGF and BDNF were positively related to the expressions of synaptophysin( r1 = 0. 892, r2 = 0. 995, P lt; 0. 05) and neurofilament( r1 = 0. 949, r2 =0. 936, P lt;0. 05) , also positively related to the airway hyperresponsiveness ( r1 =0. 929, r2 = 0. 910, P lt; 0. 05) . Conclusion RSV infection results in increased expressions of NGF and BDNF in the lung, which are correlated to the change of airway neural plasticity and airway hyperresponsiveness.
Objective Respiratory syncytial virus ( RSV) is a primary cause of lower respiratory tract infections in children, and is also the cause for the development of asthma primarily in infants. However,the immunological mechanisms by which RSV enhances allergic sensitization and asthma remain unclear. The aimof this study was to examine the influence of RSV-infected airway epithelial cells on the activation and functions of rat myeloid dendritic cells ( mDCs) . Methods Rat airway epithelial cells ( RAECs) were infected by RSV. Then RSV-infected RAECs were co-cultured with rat mDCs, and the expression of cytokine and maturation markers on mDCs were examined by real time PCR and flow cytometry. To confirm this functional mDC maturation, allergenic mixed lymphocyte reaction ( MLR) were performed. Results Wefound that functional maturation of mDCs was induced by RSV-treated RAECs, as shown by their enhanced levels of OX40L and thymus- and activation-regulated chemokine ( TARC) mRNAs, which increased the expressions of major histocompatibility complex II ( MHCII) and CD86 costimulatorymolecules and promotedT-cell proliferation in mixed lymphocyte reactions. Conclusion Our results suggest that RSV-infected epithelial cells promote the maturation of mDCs that might support Th2 cell polarization and contribute to the pathogenesis of asthma.
【Abstract】 Objective To investigate the effects of respiratory syncytial virus ( RSV) infection on the dynamic changes of airway hyperresponsiveness ( AHR) in ovalbumin ( OVA) -induced asthma in mice.Methods 60 BALB/c female mice were randomly divided into PBS control group ( A group, n = 6) , OVA group, OVA/RSV group, dexamethasone group ( D group, n =6) . Kinetics of AHR of OVA group mice was carried out on day 21, 25, 29 and 33 ( B1, B2, B3, B4 groups, n =6) , and the same with the OVA /RSV group( C1, C2, C3, C4 groups, n = 6 ) . The mouse asthma model was established by OVA-sensitization of intraperitoneal injection and repeated inhalation of OVA while the mice in OVA/RSV group were treated with combined intranasal inoculation with RSV ( 1. 0 ×106 pfu/mL in 50 μL) . Airway resistance of expiringphase ( RL ) and compliance of throax and lung ( CTL ) with different doses of acetylcholine ( Ach) were measured. Lung tissue sections were stained with hematoxylin and eosin ( HE) and periodic acid-Schiff ( PAS) for general morphology. Results Compared with B1 group, RL increased and CTL decreased in C1 group when Ach dose is above 5 g/L ( P lt; 0. 05, respectively) , and the effects prolonged ( 6 d, 10 d after challenge with OVA, respectively) much more than B1 group ( 2 d after challenge with OVA) . Compared with C1 group, RL decreased and CTL increased in D group and the infiltration of inflammatory cells was obviously alleviated in C1 group after treatment with dexamethasone. Conclusions Airway hyperresponsiveness increases obviously in OVA-sensitized and RSV-infected mice. The prolonged increase inRL and decrease in CTL ( 6 d, 10 d, respectively) may imply that RSV infection aggravates airway inflammation. The small airway inflammation may play a critical role in the persistence of airway hyperresponsiveness.
Objective To observe the immune responses of T helper cells 17 ( Th17) to respiratory syncytial virus ( RSV) infection induced lung inflammation in mice, and explore its roles on the host immune responses to RSV.Methods Female BALB/ c mice aged 3 to 5 weeks were randomly divided into a RSV group ( n=18) and a control group ( n = 12) . The mice were intranasally administrated by a 107.5 50% tissue culture infective dose ( TCID50) of RSV in 0.1 mL of culture medium. Sterile medium ( 0.1 mL/ mouse) was used as control. After infected on 1st , 4th, 8th day, the mice were sacrificed, and specimens from the lungs and lymph nodes were collected. The lung sections were stained by hematoxylin-eosin to observe the changes of lung inflammation after RSV infection. IL-17A, IL-17F and IL-23p19 mRNA expressions in the lung tissue were determined by real-time PCR. The frequencies of Th17 subsets in hilar lymph node were analyzed by flow cytometry. Results On 4th day after RSV infection, a typical lung interstitial inflammation was observed. However, this inflammation was alleviated on 8th day after RSV infection. The viral load in the lung tissue on 4th day after RSV infection were 9.208 ±0.548, which was the highest among all RSV subgroups ( P lt;0.001) . IL-23p19 and IL-17A cytokine expressions in the lung tissue were significantly increased on 4th day and 8th day after RSV infection compared with control groups ( P lt;0.01) , and the peak was on 4th day. However, IL-17F mRNA expression in the lung tissue on different day after RSV infection had no significant difference compared with the control group ( P gt;0.05) . The frequencies of Th17 subsets in hilar lymph node on 4th day and 8th day after RSV infection were ( 0.37 ±0.043) % and ( 0.853 ±0.048) % respectively, which were higher than those in control groups ( P lt;0.05) . The frequencies of Th17 on 8th day after RSV infection were significantly higher than that on 4th day after RSV infection ( P lt; 0.01) . Conclusions The expression of IL-17A in the lung tissue is increased and the level of Th17 cells in hilar lymph nodes is also elevated in the lung infected by RSV, which indicates that Th17 cells might be involved in host antiviral immune.
Objective To investigate the effects of montelukast ( MK) on the airway inflammation and the risk of the recurrence of wheezing in the treatment of infants with RSV bronchiolitis.Methods 60 infants ( aged 6-24 months) with RSV bronchiolitis admitted between December 2010 and December 2011 were recruited in the study. They were randomly assigned into a conventional group and a MK group ( n =30 in each group) . All patients received conventional treatments including inhalation of budsonide and so on.The subjects in the MK group received oral montelukast ( 4 mg qn for 12 weeks) additionally. The levels of serum cysteinyl leukotrienes ( CysLTs ) , total immunoglobuline E ( T-IgE) , eosinophil cationic protein ( ECP) and fractional exhaled nitric oxide ( FeNO) were assayed before and after the treatments. Thenumber of recurrence of wheezing was recorded through outpatient and telephone follow-up for 12 months. 30 healthy infants participating the health examination in outpatient were selected as control, and those who got atopic disease or respiratory tract infections recently were excluded. Results The levels of CysLTs, ECP and FeNO of the patients with RSV bronchiolitis before treatment were significantly higher than those in the normal control group, and the levels of CysLTs and FeNO were significantly decreased after treatment ( P lt;0. 05) . The levels of CysLTs and FeNO after treatment in the MK group was significantly lower than those in the conventional group. The level of ECP was significantly decreased after treatment in the MK group ( P lt;0. 05) ,·186· Chin J Respir Crit Care Med, March 2013 , Vol. 12 , No. 2 http: / /www. cjrccm. com which was not significantly changed in the conventional group( P gt; 0. 05) . The number of recurrence of wheezing in the MK group was more less that that in the conventional group ( P lt; 0. 05) . Conclusion Maintenance treatment with montelukast after the treatment of the acute phase of bronchiolitis can prevent recurrence of wheezing by suppressing airway inflammation in infants with RSV bronchiolitis.
ObjectiveTo explore the expressions of nerve growth factor (NGF) and leukemia inhibitory factor (LIF) in both asthmatic mice and respiratory syncytial virus(RSV)-infected mice,explore if there is a same neurogenic mechanism between ashtma and RSV infection,in order to find a new treatment target for asthma. MethodsOne hundred healthy Balb/c inbred mice were randomly divided into a control group,a RSV group,an asthma group,an asthma with RSV group,and a dexamethasone group. The lung tissue pathology was observed by hematoxylin-eosin staining(HE). The quantitative analysis of NGF mRNA and LIF mRNA of lung tissue was detected by RT-PCR. The expression of NGF protein and LIF protein was detected by immunohistochemical method. ResultsUnder light mocroscope,there were alveolar septum widening,alveolar epithelium swelling,and interstitial edema in the RSV group. There were widen alveolar septum,narrowed bronchial lumen,thicken bronchial wall and a large number of inflammatory cells infiltration around the small blood vessels,alveolar and bronchioles both in the asthma group and the asthma with RSV group,with the latter being more serious. Compared with the RSV group,the inflammation was relieved significantly in the dexamethason group. There were mRNA and protein expressions of NGF and LIF in all groups, which were highest in the asthma with RSV group,then the RSV group and the asthma group,and lowest in the dexamethasone group. ConclusionsThe expressions of LIF and NGF in the lung of mice after RSV infection and futher increase when combined with asthma. Dexamethason can inhibit the expression of NGF and LIF to some extent.
Objective To investigate expression level of interleukin-27 (IL-27)and its impact on virus replication in lung after infected with respiratory syncytial virus (RSV). Methods In vivo,7-week aged female C57 mice were infected with RSV and sacrificed on day 0,0.5,1,2,4,6,8 (n=5).The left lung was extracted for RNA,and then real-time PCR was used to detect the mRNA levels of IL-27p28,IL-27EBI3, RSV-M protein and interferon-β (IFN-β).The right lung was used for HE staining.In vitro, human lung epithelial cells (A549)were infected with RSV,and stimulated with different concentrations of recombinant human interleukin 27 (rhIL-27)in doses of 0,1ng/mL,10ng/mL,and 50ng/mL.After 24 hours,the mRNA expression of interferon induced transmembrane protein 3 (IFITM3),IFN-β,and RSV-M protein were determined by real-time PCR.IFITM3 and STAT1/pSTAT1 protein expression levels were detected by Western blot. Results The viral load in the lungs of mice peaked on 4 day post infection (DPI),then gradually decreased,and almost returned to normal on 8 DPI.IFN-β increased transiently 12 hours after infection,and then quickly returned to normal baseline.IL-27 p28/EBI3 levels peaked on 1 DPI,then gradually decreased to normal on 4 DPI.Stimulating RSV-infected A549 cells with rhIL-27 of 10ng/mL and 50ng/mL significantly inhibited viral replication,enhanced IFTIM3 mRNA expression,and induced STAT1 phosphorylation.However,rhIL-27 stimulation did not affect IFN-β mRNA expression. Conclusions The IL-27 mRNA expression increases after RSV infection.The inhibition of IL-27 on RSV replication might be related to up-regulation of STAT1 phosphorylation and IFITM3 protein expression.
ObjectiveTo systematically review the protective effect of serum maternal respiratory syncytial virus (RSV) antibodies on infants with RSV infection. MethodsPubMed, EMbase, The Cochrane Library, CBM, CNKI and WanFang Data databases were electronically searched to collect observational studies on the correlation between serum maternal RSV antibodies and infants with RSV infection from inception to July 18, 2021. Two reviewers independently screened literature, extracted data and assessed the risk of bias of the included studies, then, qualitative analysis was performed. ResultsA total of 19 studies were included, and 60% of those studies suggested that a higher level of maternal antibodies could prevent RSV infection. However, the remaining 40% of them showed that there was no significant difference in the level of RSV maternal antibodies between the infected group and the non-infected group. Further more, in the studies of the correlation between maternal antibody level and disease severity after RSV infection, 55% of those showed that maternal antibody level was negatively correlated with disease severity. ConclusionThe protective effect of serum maternal RSV antibodies on infants reported in different studies varies. Whether it can prevent RSV infection and affect the severity of RSV infected children still needs to be explored.