| The effects of BCG on airway allergic diesase have received increasingly concerns. Clinical investigations demonstrate that there was a strong inverse association between delayed hypersensitivity to Mycobacterium tuberculosis and atopy, afterwards lots of studies support this view, many animal experiments demonstrate the protective effects of BCG on asthmatic mouse models. BCG-PSN consisted with nucleic acid and polysaccharide is extracted from inactivated BCG. Our previous experiments confirmed that BCG-PSN by intraperitoneal injection before sensitization can provide effective protection on asthmatic mice, however, whether the effect of BCG-PSN on asthmatic mouse models depended on the routes of administration(especially for airway local administration) and the intervention time is poorly understood.The first part of this study was to explore the effect of BCG-PSN intervention by different routes and in different times on airway inflamation and airway hyperresponsiveness in asthmatic mouse model.The allergic rhinitis is a kind of allergic airway disease,the coexistence of allergic rhinitis and asthma is very common.Lots of studies demonstrated the protective effect of BCG on mouse models of allergic rhinitis and asthma, also there was a clinical study indicated that BCG-PSN had a symptomatic effect on allergic rhinitis patients.but the mechanism of this protective effect is still unclear.The latest studies found that the allergic disease of airway was associated with an immune disturbance of exuberant Th2 activity and releasing many Th2 cytokines.Animal experiments indicated that IFN-gamma produced during Th1 immune response against BCG suppresses the release of IL-4,IL-5,IL-13 produced by Th2 cells.In second part of this study an mouse model of allergic rhinitis was established, the effects of BCG-PSN on nasal airway resistance and upper airway inflammation on allergic rhinitis mouse models were investigated.This study tried to confirm whether BCG-PSN had a protective effect on allergic rhinitis and the possible mechanism,provided theoretical evidence for the clinical application of BCG-PSN. ObjectiveTo investigate the effects of BCG polysaccharide nucleotide ( BCG-PSN ) by different routes and at different time on airway hyperresponsiveness and airway inflammation in asthmatic mouse model.MethodsFemale Balb/c mice were sensitized with ovalbumin ( OVA ) by intraperitoneal injection on day 0, 7 and 14, then challenged with OVA by intranasal administration on day 28, 29, 30 for asthmatic model.The mice were randomized BCG-PSN treatment groups,control group,asthma group,10-12 mice each group.The control group was sensitized and challenged with saline in the corresponding time. BCG-PSN treatment groups were assigned to receive BCG-PSN by intramuscular injection(im),intranasal administration after anesthesia(in),nebulization(neb). Mice were intervened with BCG-PSN by intranasal administration after anesthesia at different times as follows: 7 days before the first sensitization (-7d in),one hour before the last challenge(+30d in),both time as above(-7+30d in),one hour before the last two challenges(29+30d in) . Airway hyperresponsiveness (AHR) was assessed using a single-chamber,whole body plethysmograph (WBP systerm,Bxcuo,USA) 48 hours after the last challenge. The result of AHR was expressed as enhanced expiratory pause(Penh).The provocative concentration of Mch that increased Penh to 200% of baseline(PC100) was obtained by linear interpolation of the concentration response curve between the two final doses of the repective provocation agent.Bronchoalveolar lavage fluid( BALF ) and lung tissues were obtained after BHR measurement.Results The AHR and airway inflammation in asthma group were much severer compare to control group. The Penh value in (in) group and (neb) group at methacholine concentration 6.25-12.5 mg/ml were significantly lower than asthma group(p<0.05);and only at 12.5 mg/ml in (im) group; there were no significant difference among the three intervention group. PC100 was higher in (neb) group(8.2±5.2mg/ml) and (in) group (7.4±4.1 mg/ml)than asthma group(3.9±0.9 mg/ml)(p<0.01, p<0.05).The percentage of Eos in BALF was (47.4%±5.6%) in asthma group, decreased markedly in (in) group(41.4%±9.9%)( p<0.05); there was no difference among (im) group(42.8%±6.4mg/ml),(neb) group (48.0%±4.7%) and asthma group.The Penh value in (-7d in) group and (-7d+30d in) group at methacholine concentration 12.5 mg/ml were significantly lower than asthma group(p<0.05). PC100 was significant higher in (-7d in,-7+30d in) group (11.6±6,12.6±6.8)mg/ml campared to asthma group(4.9±3.1)mg/ml(p<0.01). The percentage of Eos in BALF was decreased markedly in (-7d in,-7d+30d in)group (48.4%±4.9%,47.3%±6.9%) campared to the asthma group (56%±6.2%)(p<0.01).ConclusionsThe effects of BCG-PSN on AHR and airway inflamation by intratracheal administration (intranasal administration after anesthesia) is superior to intramuscular injection; BCG-PSN administrated before sensitization rather than after challenge can prevent the grogression of asthma mouse models. BCG-PSN intervented by intratracheal route maybe potential for management of asthma.PartⅡThe effects of bacilli Calmette Guerin-polysaccharide nucleic acid on nasal airway resistance and upper airway inflammation on allergic rhinitis miceObjectiveTo investigate the effect of BCG-PSN on the nasal airway resistance(RNA) and upper airway inflammation on allergic rhinitis mice. MethodsFemale Balb/c mice at 5-6 weeks of age were sensitized with ovalbumin (OVA) by intraperitoneal injection and then challenged with OVA by consciously intranasal administration for allergic rhinitis model. the mice were intervened by different doses of BCG-PSN in intranasal route(10μg,5μg,1μg) and nebulizing route 7 days before the sensitization, all mice were divided into 6 group: saline group,allergic rhinitis group,10μg,5μg,1μg intranasal administration group and nebulize group. The allergic symptoms such as sneezing,scratch nose were recorded in 10min after the last challenge. The posterior nasal pressure was measured with a syringe pump and a pressure transducer 24h after the last challenge. The RNA was obtained according to the fluid statics . The nasal tissues were fixed and prepared into the paraffin sections after nasal resistance measurement. Then paraffin sections were stained with hematoxylin and eosin. the number of Eos in per unit area was counted and the thichness in the lower portion of nasal septum measured.ResultsCompare with the rhinitis group, the symptoms such as sneeze and scratch nose in 4 interventions groups were less serious, especially in 10μg group and nebulize group. The RNA of expiration in saline group was 1.84±0.38cmH2O ml-1s-1,the RNA of inspiration was 1.54±0.44 cmH2O ml-1s-1; the RNA of expiration in rhinitis group was 2.41±0.35 cmH2O ml-1s-1, the RNA of inspiration was 2.28±0.55 cmH2O ml-1s-1. There is statistical significant difference between AR group and control group, p<0.01. The RNA of expiration and inspiration in 4 interventions groups were no statistical difference with rhinitis group. But compare with the saline group, the RNA of expiration in 10μg,5μg and the RNA of inspiration in 10μg,nebulize group were no statistical difference with is. The nasal pathology shows that the mucosal thichness in rhinitis group(80.5±20.5μm)was evidently higher than saline group(46.7±2.5μm), p<0.05; and in 10μg group(51.7±3.5μm),nebulize group(52.7±8.0μm),the mucosal thichness were lower than rhinitis group, p<0.05. In rhinitis group compare with saline group, the number of Eos in per unit area (0.1mm2)was increased(26.2±10.5 vs 0.4±0.07),p<0.001. And in 10μg group(5.9±1.8),nebulize group(11.2±6.7) the Eos were decreased compare with rhinitis group, p<0.05. ConclusionsBCG-PSN can alleviate upper airway inflammation of allergic rhinitis mice.The routes of intervention with BCG-PSN by intranasl and nebulizing adminstration are also effective for managing allergic rhinitis. |
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