Metabolic changes in the mouse kidney after subcutaneous injection of butyl 2-chloroethyl sulfide

Mustard gas toxicity: the acute and chronic pathological effects

Ever since it was first used in armed conflict, mustard gas (sulfur mustard, MG) has been known to cause a wide range of acute and chronic injuries to exposure victims. The earliest descriptions of these injuries were published during and in the immediate aftermath of the First World War, and a further series of accounts followed the Second World War. More recently, MG has been deployed in warfare in the Middle East and this resulted in large numbers of victims, whose conditions have been studied in detail at hospitals in the region. In this review, we bring together the older and more recent clinical studies on MG toxicity and summarize what is now known about the acute and chronic effects of the agent on the eyes, skin, respiratory tract and other physiological systems. In the majority of patients, the most clinically serious long-term consequences of MG poisoning are on the respiratory system, but the effects on the skin and other systems also have a significant impact on quality of life. Aspects of the management of these patients are discussed.

Effect of nitrogen mustard, a vesicant agent, on lymphocyte energy metabolism

BACKGROUND

The vesicant agents sulfur and nitrogen mustards, which contain chloroethyl groups, are potent inhibitors of DNA synthesis and cell growth, likely changing the utilization of anaerobic glycolysis for energy generation.

METHODS

To investigate the effect of nitrogen mustard on cellular energy metabolism, lymphocytes treated with increasing doses of mechlorethamine (HN2), a nitrogen mustard and an analogue of sulfur mustard, were incubated with radiolabeled glucose. The rates of aerobic and anaerobic glycolysis were then determined.

RESULTS

Glycogen consumption was significantly higher in cells treated with HN2 in a dose-dependent manner compared to untreated cells. Similarly, the amount of end-product lactate was increased, but CO2 was reduced in HN2-treated cells.

CONCLUSIONS

Lymphocytes normally use aerobic glycolysis under aerobic conditions, but energy metabolism predominantly involved anaerobic glycolysis after severe intoxication with mustard agent.

Biochemical changes in mouse lung after subcutaneous injection of the sulfur mustard 2-chloroethyl 4-chlorobutyl sulfide

Sulfur mustard (HD) is a vesicant-type chemical warfare agent (CWA) introduced in World War I which continues to be produced, stockpiled, and occasionally deployed by some countries, and could be used potentially by terrorists. Exposure to HD can cause erythema, blisters, corneal opacity, and airway damage. We have reported previously that subcutaneous (SC) injection of immunodeficient athymic nude mice with the half mustard butyl 2-chloroethyl sulfide (BCS) causes systemic biochemical changes in several organs distal to the exposure site. In the present study, we examined the response of non-immunodeficient Swiss Webster mice to the mustard, 2-chloroethyl 4-chlorobutyl sulfide (CECBS). In a pilot study, we found that a single SC injection of 20-25 microl/mouse causes death within 24h. Consequently, we used 5 microl/mouse (approx. 0.017 mg/kg body weight) of neat CECBS or an equal volume of saline as control. We examined the lungs after 1, 24, and 48 h for biochemical changes including total and oxidized glutathione, protein, DNA, and lipid peroxidation contents in tissue homogenate, and superoxide dismutase, catalase, glucose-6-phosphate dehydrogenase, and glutathione S-transferases activities in the cytosol. After 1h and/or 24h, we found statistically significant changes that were resolved by 48 h. These changes mimicked those of HD and BCS and were generally consistent with free radical-mediated oxidative stress. The implications of these observations are two-fold. First, dermal exposure to low-dose mustard gas could elicit systemic changes impacting distal organs such as the lungs. It also suggests that antioxidants could potentially modulate the response and reduce the damage. Second, although the use of known CWAs such as HD is prohibited, analogs that are not recognized as agents are as toxic and could be dangerous if acquired and used by potential terrorists.

Reactivity of chloroethyl sulfides in the presence of a chlorinated prophylactic: a kinetic study by EPR/spin trapping and NMR techniques

This study reports the kinetic reaction of a chlorinated glycoluril, 1,3,4,6-tetrachloro-7, 8-diphenyl-2,5-diimino glycoluril, also known as S-330, with butyl 2-chloroethyl sulfide (half-sulfur mustard, H-MG) and bis-(2-chloroethyl) sulfide (sulfur mustard, HD) using electron paramagnetic resonance (EPR)/spin trapping and nuclear magnetic resonance (NMR) techniques. Both H-MG and HD are highly reactive in water and are capable of alkylating a variety of critical target molecules. It is well known that compounds containing reactive chlorine are useful neutralizers of HD and other vesicating agents. Organic compounds containing a chloroamide group are generally preferred. Currently, the reactive mechanism of this chlorinated glycoluril with these chloroethyl sulfides has not been documented. The kinetic experiments were performed by adding the monofunctional sulfur mustard (H-MG) directly to the spin trap agent alpha-phenyl-N-tert-butylnitrone (PBN, pH 7.1). The intensity of the EPR spectra obtained from the resulting spin adduct (hyperfine coupling constants aN = 1.45 mT and abetaH = 0.225 mT) was sensitive to the rate at which the spin adduct was formed. Different concentrations of the chloroamide were added to the reaction mixtures of PBN and H-MG. The EPR spectra of separate identical reaction mixtures were recorded with the spectrometer set for kinetic experiments. The rate constant determined by EPR was 1.78 +/- 0.14 x 10(7) M(-1)s(-1). It was found that S-330 reacts 55 times faster than PBN. The results obtained for S-330 by EPR indicate that S-330 is an efficient scavenger of H-MG. Furthermore, a 13C-NMR chemical shift of 0.903 +/- 0.002 ppm was observed for the Cl-N-C-N-Cl carbon in S-330 after exposure to HD (1 mM). In addition, the decay of 13C-NMR resonance at 91.7 ppm chemical shift was observed in the presence of HD. The 13C-NMR data showed that the formation of the ethylene sulfonium ion usually found in the case of HD was not observed in the presence of S-330.

Importance of glucose-6-phosphate dehydrogenase activity for cell growth

The intracellular redox potential, which is determined by the level of oxidants and reductants, has been shown to play an important role in the regulation of cell growth. The principal intracellular reductant is NADPH, which is mainly produced by the pentose phosphate pathway through the actions of glucose-6-phosphate dehydrogenase (G6PD), the rate-limiting enzyme of the pentose phosphate pathway, and by 6-phosphogluconate dehydrogenase. Previous research has suggested that an increase in G6PD activity is important for cell growth. In this article, we suggest that G6PD activity plays a critical role in cell growth by providing NADPH for redox regulation. The results show the following: 1) inhibition of G6PD activity abrogated growth factor stimulation of [3H]thymidine incorporation in all cell lines tested; 2) overexpression of G6PD stimulated cell growth, as measured by an increase in [3H]thymidine incorporations as compared with cells transfected with vector alone; 3) inhibition of G6PD caused cells to be more susceptible to the growth inhibitory effects of H2O2; 4) inhibition of G6PD led to a 30-40% decrease in the NADPH/NADP ratio; and 5) inhibition of G6PD inhibited cell anchorage and significantly decreased the growth-related stimulation of tyrosine phosphorylation.

Free radical-mediated lung response to the monofunctional sulfur mustard butyl 2-chloroethyl sulfide after subcutaneous injection

Vesicant-induced pathogenesis is initiated by rapid alkylation and cross-linking of DNA purine bases causing strand breaks leading subsequently to NAD depletion and cell death. We postulated that vesicants may also be associated with free radical-mediated oxidative stress distal to the site of exposure. To test this postulate in the lung, we injected 3 groups (n = 8) of 5-month-old, male, athymic, nude mice, weighing 30-35 g with a single subcutaneous (s.c.) injection (5 microliters/mouse) of butyl 2-chloroethyl sulfide (BCS), a monofunctional sulfur mustard analog. After 1, 24 and 48 h, we euthanized the treated mice along with 2 untreated control mice at each time point. We then pooled the control mice in one group (n = 6) and analyzed the lungs for biochemical indices of oxidative stress. We found that total lung weight was not altered after treatment, but wet/dry weight ratio decreased 18% (P less than 0.05) and hemoglobin content increased 50% and 36% at 1 and 24 h, respectively. The activity of glucose-6-phosphate dehydrogenase increased significantly, 40% at 1 and 24 h and 84% at 48 h and that of glutathione S-transferases was 60%, P less than 0.05 greater at all time points. Lipid peroxidation (estimated by the thiobarbituric acid test) and total protein content increased 3-fold and 2-fold, at 1 and 24 h, respectively. Total and oxidized glutathione contents were significantly elevated, 38% at 1 h and 64% at 24 h for the former and 45% at 24 h and 56% at 48 h for the latter. Because these changes are consistent with the cellular response to oxidative stress, we conclude that BCS injected subcutaneously, can cause changes in the lung possibly via a free radical-mediated mechanism.