细菌溶解产物及全反式维甲酸对哮喘小鼠气道炎症的影响

Effects of bacterial lysates and all trans-retinoic acid on airway inflammation in asthmatic mice

摘要:

目的 通过观察细菌溶解产物（OM-85BV）及全反式维甲酸（ATRA）对哮喘小鼠气道炎症的影响，探讨OM-85BV及ATRA对哮喘小鼠气道炎症的免疫调节机制。方法 40只雌性BALB/c小鼠随机分为正常对照组、模型组、OM-85BV组、ATRA组和OM-85BV+ATRA组。采用卵清蛋白（OVA）致敏及激发建立支气管哮喘小鼠模型。第25~34天于每次雾化激发前OM-85BV组、ATRA组、OM-85BV+ATRA组均予相应药物灌胃。正常对照组腹腔注射致敏及雾化吸入激发，以及正常对照组、模型组灌胃均以生理盐水代替。末次激发后24~48 h麻醉并解剖小鼠，采集小鼠右肺灌洗液（BALF），采用ELISA法检测IL-10、IL-17表达水平；采集小鼠左肺行苏木精-伊红染色观察肺组织病理学改变，采用荧光定量PCR检测ROR-γT mRNA的相对表达量。结果 与正常对照组相比，模型组小鼠支气管管腔缩小，管腔内分泌物增多，支气管周围及肺泡壁可见大量炎性细胞浸润；模型组IL-10水平降低（P < 0.05），IL-17及ROR-γT mRNA水平升高（P < 0.05）。与模型组相比，OM-85BV组、ATRA组和OM-85BV+ATRA组小鼠支气管周围及肺泡壁可见炎性细胞浸润减少；OM-85BV组BALF中IL-10水平明显增高（P < 0.05），IL-17及ROR-γT mRNA水平均下降（P < 0.05）；ATRA组BALF中IL-17及ROR-γT mRNA水平均下降（P < 0.05）。与OM-85BV组相比，ATRA+OM-85BV组ROR-γT mRNA的相对表达量明显增加（P < 0.05）。与ATRA组相比，ATRA+OM-85BV组BALF中IL-10及IL-17水平均有升高（P < 0.05）。结论 OM-85BV和ATRA均可改善哮喘小鼠呼吸道炎症。但是二者联合用药并没有较单独用药干预有更明显的疗效。

Abstract:

Objective To observe the effects of bacterial lysates (OM-85BV) and all trans-retinoic acid (ATRA) on airway inflammation in asthmatic mice, and to investigate the immunoregulatory mechanism of OM-85BV and ATRA for airway inflammation in asthmatic mice. Methods Forty female BALB/c mice were randomly divided into five groups: normal control, model, OM-85BV, ATRA, and OM-85BV+ATRA. A bronchial asthma model was established by intraperitoneal injection of ovalbumin (OVA) for sensitization and aerosol challenge in all mice except those in the normal control group. On days 25-34, before aerosol challenge, the model, OM-85BV, ATRA, and OM-85BV+ATRA groups were given normal saline, OM-85BV, ATRA, and OM-85BV+ATRA respectively by gavage. Normal saline was used instead for sensitization, challenge, and pretreatment before challenge in the normal control group. These mice were anesthetized and dissected at 24-48 hours after the final challenge. Bronchoalveolar lavage fluid (BALF) was collected from the right lung to measure the levels of interleukin-10 (IL-10) and interleukin-17 (IL-17) by ELISA. The left lung was collected to observe histopathological changes by hematoxylin-eosin staining. The relative expression of ROR-γT mRNA was measured by quantitative real-time PCR. Results Compared with the normal control group, the model group showed contraction of the bronchial cavity, increased bronchial secretions, and a large number of infiltrating inflammatory cells around the bronchi and alveolar walls, as well as a significantly reduced level of IL-10 (P < 0.05) and significantly increased levels of IL-17 and ROR-γT mRNA (P < 0.05). Compared with the model group, the OM-85BV, ATRA, and OM-85BV+ATRA groups showed a significant reduction in infiltrating inflammatory cells around the bronchi and alveolar walls; the OM-85BV group showed a significant increase in the level of IL-10 in BALF (P < 0.05) and significant reductions in the levels of IL-17 and ROR-γT mRNA (P < 0.05); the ATRA group showed significant reductions in the levels of IL-17 and ROR-γT mRNA (P < 0.05). Compared with the OM-85BV group, the OM-85BV+ATRA group had significantly increased relative expression of ROR-γT mRNA (P < 0.05). Compared with the ATRA group, the OM-85BV+ATRA group had significantly increased levels of IL-10 and IL-17 in BALF (P < 0.05). Conclusions Both OM-85BV and ATRA can reduce respiratory inflammation in asthmatic mice. However, a combination of the two drugs does not have a better effect than them used alone.