Abdominal bloating and irritable bowel syndrome like symptoms following microinstillation inhalation exposure to chemical warfare nerve agent VX in guinea pigsDepartment of Biochemical Pharmacology/Division of Biochemistry, Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, MD 20910-7500, USA,
Department of Biochemical Pharmacology/Division of Biochemistry, Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, MD 20910-7500, USA
Medical Toxicology Branch/Analytical Toxicology Division, United States Army Medical Research Institute of Chemical Defense, 3100 Ricketts Point Road, Edgewood, MD 21010, USA
Department of Biochemical Pharmacology/Division of Biochemistry, Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, MD 20910-7500, USA
Department of Biochemical Pharmacology/Division of Biochemistry, Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, MD 20910-7500, USA
Medical Toxicology Branch/Analytical Toxicology Division, United States Army Medical Research Institute of Chemical Defense, 3100 Ricketts Point Road, Edgewood, MD 21010, USA
Department of Biochemical Pharmacology/Division of Biochemistry, Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, MD 20910-7500, USA, madhusoodana.nambiar{at}na.amedd.army.mil, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA While assessing the methylphosphonothioic acid S-(2-(bis(1-methylethyl)amino)ethyl)O-ethyl ester (VX) induced respiratory toxicity and evaluating therapeutics against lung injury, we observed that the animals were experiencing abnormal swelling in the abdominal area. Nerve agent has been known to increase salivary, nasal and gastrointestinal secretion and cause diarrhea. This study was initiated to investigate the effect of VX on the gastrointestinal tract (GI) since abdominal pathology may affect breathing and contribute to the on going respiratory toxicity. The mid-abdominal diameter and the size of the lower left abdomen was measured before and after 27.3 mg/m3 VX exposure by microinstillation and at 30min intervals up to 2h post-VX exposure. Both VX and saline exposed animals exhibited a decrease in circumference of the upper abdomen, although the decrease was slightly higher in VX-exposed animals up to 1 h. The waist diameter increased slightly in VX-exposed animals from 60 to 90min post-VX exposure but was similar to saline controls. The lower left abdomen near to the cecum, 6 cm below and 2 cm to the right of the end of the sternum, showed an increase in size at 30—60 min that was significantly increased at 90—120 min post-VX exposure. In addition, VX-exposed animals showed loose fecal matter compared to controls. Necropsy at 24 h showed an increased small intestine twisting motility in VX-exposed animals. Body tissue AChE assay showed high inhibition in the esophagus and intestine in VX-exposed animals indicating that a significant amount of the agent is localized to the GI following microinstillation exposure. These results suggest that microinstillation inhalation VX exposure induces gastrointestinal disturbances similar to that of irritable bowel syndrome and bloating.
Key Words: abdominal • acetylcholinesterase • bloating • chemical warfare nerve agents • guinea pig • inhalation exposure • microinstillation • organophosphates • pulmonary injury • respiratory system • swelling
Toxicology and Industrial Health, Vol. 23, No. 4,
231-240 (2007) |
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