Drosophila melanogaster larvae as a model for blast lung injury.

BACKGROUND: Primary blast injuries, specifically lung injuries, resulting from blast overpressure exposures are a major source of mortality for victims of blast events. However, existing pulmonary injury criteria are inappropriate for common exposure environments. This study uses Drosophila melanogaster larvae to develop a simple phenomenological model for human pulmonary injury from primary blast exposure. METHODS: Drosophila larvae were exposed to blast overpressures generated by a 5.1-cm internal diameter shock tube and their mortality was observed after the exposure. To establish mortality thresholds, a survival analysis was conducted using survival data and peak incident pressures. In addition, a histologic analysis was performed on the larvae to establish the mechanisms of blast injury. RESULTS: The results of the survival analysis suggest that blast overpressure for 50% Drosophila survival is greater than human threshold lung injury and is similar to human 50% survival levels, in the range of overpressure durations tested (1-5 ms). A "parallel" analysis of the Bass et al. 50% human survival curves indicates that 50% Drosophila survival is equivalent to a human injury resulting in a 69% chance of survival. Histologic analysis of the blast-exposed larvae failed to demonstrate damage to the dorsal trunk of the tracheal system; however, the presence of flocculent material in the larvae body cavities and tracheas suggests tissue damage. CONCLUSIONS: This study shows that D. melanogaster survival can be correlated with large animal injury models to approximate a human blast lung injury tolerance. Within the range of durations tested, Drosophila larvae may be used as a simple model for blast injury.