[Diffuse aspiration bronchiolitis (DAB) produced in animals by repeated HCl microaspiration]

We recently reported that diffuse aspiration bronchiolitis (DAB) was detected in 1% of autopsied lungs of aged cases of pneumonia. We hypothesized whether repeated HCl micro-aspiration (RHMA) is involved in DAB and established an animal model by administering HCl intratracheally to rats every two days for 2 weeks. Saline was given to control animals in the same fashion. Then, we performed bronchio-alveolar lavage (BAL) or excised lungs for histologic examination. There was no difference in BAL cell counts, TNF alpha-production, elastase-like activity or albumin levels between the HCl and control groups. Histologically, DAB-like findings were observed in the HCl-treated animals. These data suggest that RHMA might be involved in DAB, while neither TNF alpha-production nor elastase-like activity may play a significant role in inducing DAB.