Oral instillation with surfactant phospholipid: a reliable alternative to intratracheal injection in mouse studies

Abstract

SummaryThe intratracheal (IT) injection technique has been widely used in the mouse studies of pulmonary diseases. Here, we describe a non-invasive technique using oral instillation challenge with the surfactant phospholipid that may advantageously replace the traditional IT technique. We performed comparative studies between oral instillation and IT injection of both vectors (adeno-associated virus, AAV vector) and bacteria (Pseudomonas aeruginosa). Our results demonstrated that the oral instillation is a reliable alternative to IT injection. The administration of a fluorophore-labelled AAV vector demonstrated a similar pattern of distribution and quantity of vector delivered by oral instillation compared with IT injection. In addition, administration of AAV5-alpha-1 antitrypsin (AAT) to the lungs by oral instillation resulted in similar levels of AAT in both the lung homogenates and sera compared with the IT injection group. In our study of P. aeruginosa delivery, oral instillation resulted in similar mouse weight loss, cytokine levels in the epithelial lining fluid [interleukin (IL)-1b, IL-6, tumour necrosis factor-a, neutrophil chemokine and macrophage inflammatory protein-1a], lung histology/pathology and bacterial loads. Therefore, we conclude that oral instillation of materials mixed with surfactant phospholipid is an adequate and reproducible technique to replace the invasive IT injection procedure for the delivery of either vector or bacteria to the lungs. This procedure has the benefits of eliminating the discomfort, local inflammation and mortality associated with the more invasive IT surgical procedures.

Immunization of Mice with a Recombinant Adenovirus Vaccine Inhibits the Early Growth of Mycobacterium tuberculosis After Infection

“…Four to 30 weeks after Ad85A immunization, aerosol or intratracheal challenge with Mtb (Erdman strain, CBER/FDA) was performed as described [14], [35]. For i.n.…”

Defective Acid Sphingomyelinase Pathway with Pseudomonas aeruginosa Infection in Cystic Fibrosis

“…Oropharyngeal instillation with surfactant phospholipids is a reliable alternative to intratracheal injection for establishing lung infection in mice (31). To prepare for the inoculum, P. aeruginosa were grown into mid-logarithmic phase.…”

Respiratory Tract Deposition and Distribution Pattern of Microparticles in Mice Using Different Pulmonary Delivery Techniques

“…As mentioned earlier, these techniques require technical expertise and anesthetization of animals prior to administration, and repeated dosing may cause inflammation and injury to the trachea. An alternative technique to IT installation and tracheostomy is oropharyngeal aspiration, which can potentially overcome some of the challenges mentioned above [ 23 , 24 , 31 ]. Lakatos et al compared oropharyngeal aspiration to IT instillation to establish a silica-induced fibrosis mouse model and observed that administration of silica particles by aspiration resulted in a more uniform pulmonary distribution with minimal intra-animal variability [ 32 ].…”

“…Price et al recently discussed in detail the importance of animal model selection when evaluating an inhaled product in the preclinical stage [ 20 ]. Most of the published papers evaluating inhaled drugs employ small animal models such as mice and rats due to ease of availability, affordability, and handling [ 3 , 7 , 22 , 23 , 24 ]. In this study, we evaluated three widely reported preclinical inhalation (direct) techniques: the MicroSprayer ® Aerosolizer (Penn-Century, Wyndmoor, PA, USA; recently discontinued), the BioLite Intubation System (Braintree Scientific, Braintree, MA, USA), and oropharyngeal aspiration.…”