2-Chloroethyl ethyl sulfide (CEES) or half-mustard gas, a sulfur mustard (HD) analog, is a genotoxic agent that causes oxidative stress and induces both apoptotic and necrotic cell death. Sodium pyruvate induced a necrosis-to-apoptosis shift in HaCaT cells exposed to CEES levels ≥ 1.5 mmol/L and lowered markers of DNA damage, oxidative stress, and inflammation. This study provides a rationale for the future development of multicomponent therapies for HD toxicity in the skin. We hypothesize that a combination of pyruvates with scavengers/antioxidants encapsulated in liposomes for optimal local delivery should be therapeutically beneficial against HD-induced skin injury. However, the latter suggestion should be verified in animal models exposed to HD.

We have recently reported that antioxidant liposomes can be used as antidotes for mustard gas induced lung injury in guinea pigs. The maximum protection was achieved with a liposome composed of tocopherols (α, γ, δ) and N-acetylcysteine (NAC) when administered after 5 min of exposure of 2-chloroethyl ethyl sulfide (CEES), a half sulfur mustard gas. We also reported an association of mustard gas-induced lung injury with an activation of MAPK/AP-1 signaling pathway and cell proliferation. The objective of the present study was to investigate whether CEES-induced MAPKs/AP-1 signaling pathway is influenced by antioxidant liposome therapy. A single dose (200 μl) of the antioxidant liposome was administered intratracheally after 5 min of exposure of CEES (0.5 mg/kg). The animals were sacrificed after 1 h and 30 days of CEES exposure. Although the liposome treatment did not have any significant effect on the activation of the MAPKs family (ERK1/2, p38 and JNK1/2), it significantly counteracted the CEES-induced activation of AP-1 transcription factors and corresponding increase in the protein levels of Fos, ATF and Jun family members. The liposome treatment significantly blocked the CEES-induced increase in the protein levels of cyclin D1, a cell cycle protein and PCNA, a cell differentiation marker. Furthermore, it protected lung against CEES-induced inflammation and infiltration of neutrophils, eosinophils and erythrocytes in the alveolar space. This suggests that the protective effect of antioxidant liposome against CEES-induced lung damage is mediated via control of AP-1 signaling.

Zugl.: Magisterarb.

We reported earlier in a guinea pig model that exposure of 2-chloroethyl ethyl sulfide (CEES), a mustard gas analog, causes lung injury associated with the activation of tumor necrosis factor alpha (TNF-α), mitogen activated protein kinases (MAPK) signaling, and activator protein-1 (AP-1) transcription factor. Our earlier studies also revealed that antioxidant liposomes can be used as antidotes. Proinflammatory cytokines IL-1, IL-6, and TNF-α, either alone or in combination, can induce the activation of another group of transcription factors, namely SAF-1 (serum accelerator factor-1)/MAZ (Myc-associated zinc finger protein). Phosphorylation of SAF-1 via MAPK markedly increases its DNA-binding and transactivational potential. The objective of the present study was to investigate whether CEES exposure causes activation of IL-1β, IL-6, and SAF-1/MAZ and whether these effects can be prevented by antioxidant liposomes. A single dose (200 μL) of the antioxidant liposome mixture was administered intratracheally after 5 min of exposure of CEES (0.5 mg/kg). The animals were sacrificed either 1 h or 30 days after CEES exposure. CEES exposure caused an upregulation of proinflammatory cytokines IL-6 and IL-1β in the lung along with an increase in the activation of transcription factor SAF-1/MAZ. The antioxidant liposomes treatment significantly blocked the CEES-induced activation of IL-6, IL-1β, and SAF-1/MAZ. This might suggest that antioxidant liposomes might offer a potential therapeutic strategy against inflammatory diseases associated with activation of these bioactive molecules.

The purpose of this study was to develop antioxidant liposomes as an antidote for mustard gas-induced lung injury in a guinea pig model. Five liposomes (LIP-1, LIP-2, LIP-3, LIP-4, and LIP-5) were tested with differing levels of phospholipid, cholesterol, phosphatidic acid, tocopherol (α, γ, δ), N-acetylcysteine (NAC), and glutathione (GSH). A single dose (200 μL) of liposome was administered intratracheally 5 min or 1 h after exposure to 2-chloroethyl ethyl sulfide (CEES). The animals were sacrificed either 2 h after exposure (for lung injury study) or 30 days after exposure (for histology study). The liposomes offered 9%-76% protection against lung injury. The maximum protection was with LIP-2 (71.5% protection) and LIP-4 (75.4%) when administered 5 min after CEES exposure. Delaying the liposome administration 1 h after CEES exposure decreased the efficacy. Both liposomes contained 11 mM α-tocopherol, 11 mM γ-tocopherol, and 75 mM NAC. However, LIP-2 contained additionally 5mM δ-tocopherol. Overall, LIP-2 and LIP-4 offered significant protection by controlling the recruitment of neutrophils, eosinophils, and the accumulation of septal and perivascular fibrin and collagen. However, LIP-2 showed better protection than LIP-4 against the accumulation of red blood cells in the bronchi, alveolar space, arterioles and veins, and fibrin and collagen deposition in the alveolar space. The antifibrotic effect of the liposomes, particularly LIP-2, was further evident by a decreased level of lipid peroxidation and hydroxyproline in the lung. Thus, antioxidant liposomes containing both NAC and vitamin E are an effective antidote against CEES-induced lung injury.

Freie Univ., Diss u.d.T.: Jansen, Henry: Relationality and the concept of God--Amsterdam, 1995.