Repetitive antidotal treatment is crucial in eliminating eye pathology, respiratory toxicity and death following whole-body VX vapor exposure in freely moving rats

  • E. Bloch-ShildermanEmail author
  • G. Yacov
  • L. Cohen
  • I. Egoz
  • H. Gutman
  • R. Gez
  • I. Rabinovitz
  • U. Nili
Organ Toxicity and Mechanisms


Exposure to the chemical warfare nerve agent VX is extremely toxic, causing severe cholinergic symptoms. If not appropriately treated, death ultimately ensues. Based on our previously described whole-body vapor exposure system, we characterized in detail the clinical outcome, including respiratory dynamics, typical of whole-body exposure to lethal doses of VX vapor in freely moving rats. We further evaluated the efficacy of two different antidotal regimens, one comprising a single and the other repeated administration of antidotes, in countering the toxic effects of the exposure. We show that a 15 min exposure to air VX concentrations of 2.34–2.42 mg/m3 induced a late (15–30 min) onset of obvious cholinergic signs, which exacerbated over time, albeit without convulsions. Marked eye pathology was observed, characterized by pupil constriction to pinpoint, excessive lacrimation with red tears (chromodacryorrhea) and corneal damage. Respiratory distress was also evident, characterized by a three–fourfold increase in Penh values, an estimate of lung resistance, and by lung and diaphragm histological damage. A single administration of TAB (the oxime TMB-4, atropine and the anticholinergic and antiglutamatergic benactyzine) at the onset of clinical signs afforded only limited protection (66% survival), with clinical deterioration including weight loss, chromodacryorrhea, corneal damage, increased airway resistance and late death. In contrast, a combined therapy of TAB at the onset of clinical signs and repeated administration of atropine and toxogonin (ATOX) every 3–5 h, a maximum of five i.m. injections, led to 100% survival and a prompt recovery, accompanied by neither the above-described signs of eye pathology, nor by bronchoconstriction and respiratory distress. The necessity of recurrent treatments for successful elimination of VX vapor toxicity strongly supports continuous penetration of VX following termination of VX vapor exposure, most likely from a VX reservoir formed in the skin due to the exposure. This, combined with the above-described eye and respiratory pathology and absence of convulsions, are unique features of whole-body VX vapor exposure as compared to whole-body vapor exposure to other nerve agents, and should accordingly be considered when devising optimal countermeasures and medical protocols for treatment of VX vapor exposure.


Whole-body VX vapor exposure Chromodacryorrhea Corneal damage Repetitive antidotal treatment Whole-body plethysmography Respiratory toxicity TAB ATOX Cholinesterase (ChE) Organophosphorous 







Lethal concentration




Organophosphorus nerve agents


TMB4, atropine and benactyzine


Atropine and toxogonin


Whole-body plethysmography


Compliance with ethical standards

Conflict of interest

The authors declare that there are no conflicts of interest. The views expressed in this article are those of the authors and do not reflect the official policy of the IIBR.


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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  • E. Bloch-Shilderman
    • 1
    Email author
  • G. Yacov
    • 1
  • L. Cohen
    • 1
  • I. Egoz
    • 1
  • H. Gutman
    • 1
  • R. Gez
    • 1
  • I. Rabinovitz
    • 1
  • U. Nili
    • 1
  1. 1.Department of PharmacologyIsrael Institute for Biological ResearchNess ZionaIsrael

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