Development and Testing of Treatments for Battlefield Phosgene Poisoning.
Final rept. 1 Aug 94-31 Jan 96,
NEW YORK MEDICAL COLL VALHALLA
Pagination or Media Count:
This projects aim was to characterize changes in microvascular endothelial cells HMVEC and type II alveolar epithelial cells AEpC after exposure to phosgene in vitro for evaluation of prophylaxis and therapy. We measured release of eicosanoids from lung HMVEC 6-ket-PGF1a and thromboxane B2 both increase approx. 2 h after exposure to 900 ppm-min phosgene. Smaller but statistically significant increases in leukotrienes C4, D4, and E4 are also seen after 2 h. Over the same time course, phosgene-exposed HMVEC which were not killed by exposure accumulate intracytosolic calcium measured with fluo-3, and generate reactive oxygen metabolites detected with CDCFH. After a phosgene dose of 300 ppm-min, changes in HMVEC membranes result in loss of cytosolic esterase activity detected with calcein-AM, along with increased binding of intercalating dyes to DNA. Additional signs of cell injury are decreased lysosomal uptake of acridine orange, and loss of mitochondrial membrane potential measured by rhodamine 123 uptake and JC-1 aggregation. These changes all occur rapidly after exposure and remain stable for several hours. Type II AEpC are more resistant to phosgene measures of cytotoxic injury are minimally altered by phosgene levels up to 900 ppm-min and mitochondrial membrane potential is maintained even at this dose. Intracellular calcium levels stay low even after addition of ionophores to A549 AEpC. Permeability of both type II AEpC and HMVEC monolayers increases after exposure to 900 ppmmin phosgene, measured by decreased electrical resistance and increased mannitol permeation. Pretreatment with approx. 10-2 M N-acetyl cysteine and approx. 10-4 M pyrrolidine dithiocarbamate protects against some cytotoxic changes, suggesting that intracellular reactive oxygen species may contribute to phosgene induced injury.
- *IN VITRO ANALYSIS
- WOUNDS AND INJURIES
- ELECTRICAL RESISTANCE
- PREVENTIVE MEDICINE
- Medicine and Medical Research