Table 2 Comparison of advantages and shortcomings of common ALI models with different etiologies

Direct ALI models

 Endotoxin challenge

Simple usage

The quality of reagents used may vary significantly

Direct exposure of bioactive microbial units to lungs

 Bacterial infection

High relevance to real-world scenario of ALI

Experiments require biosafety concern and attention

Direct impact of endotoxin on lung tissues

 Acidic instillation

Direct and confined damage to airways

This does not resemble gastric acid aspiration

Injury of alveolar epithelium caused by acidic insults

 Bleomycin exposure

Facile experimentation

Toxicity could be various and more than pulmonary

Induction of pulmonary fibrosis

 Oleic acid induction

Facile experimentation with high reproducibility

Delivery of insoluble oleic acid to airways is ineffective

Formation of pulmonary microvascular embolism

 Ventilation induction

Close relevance to clinical practice

Injurious patterns are significantly different between animals and human

Severe mechanical overdistention of lung structure

 Pulmonary contusion

High relevance to physical trauma

Low repeatability

Formation of thrombi in pulmonary capillaries

Indirect ALI models

 IR-induced

Consistency with pathogenic reperfusion in clinical settings

Complex operation with poor reproducibility

Increased alveolar permeability due to excessive pro-inflammatory cytokines produced by immunity

 Transfusion-caused

Clinically related with facile experimentation

Low repeatability and high dependency on blood products used

Formation of neutrophil sequestration and pulmonary edema

 Acute pancreatitis-associated

High clinical relevancy

Complicated experimentation with unpredictable outcome

Endothelial damage and vascular permeability in lungs

 CLP/CASP

High occurrence in clinical practice

Surgical operation requires sufficient skillfulness

Secondary lung impairment following intra-abdominal sepsis