Minor role of lipid peroxidation in acute bleomycin toxicity in rats

The Chemical Reactivity of Membrane Lipids

It is well-known that aqueous dispersions of phospholipids spontaneously assemble into bilayer structures. These structures have numerous applications across chemistry and materials science and form the fundamental structural unit of the biological membrane. The particular environment of the lipid bilayer, with a water-poor low dielectric core surrounded by a more polar and better hydrated interfacial region, gives the membrane particular biophysical and physicochemical properties and presents a unique environment for chemical reactions to occur. Many different types of molecule spanning a range of sizes, from dissolved gases through small organics to proteins, are able to interact with membranes and promote chemical changes to lipids that subsequently affect the physicochemical properties of the bilayer. This Review describes the chemical reactivity exhibited by lipids in their membrane form, with an emphasis on conditions where the lipids are well hydrated in the form of bilayers. Key topics include the following: lytic reactions of glyceryl esters, including hydrolysis, aminolysis, and transesterification; oxidation reactions of alkenes in unsaturated fatty acids and sterols, including autoxidation and oxidation by singlet oxygen; reactivity of headgroups, particularly with reactive carbonyl species; and E/Z isomerization of alkenes. The consequences of reactivity for biological activity and biophysical properties are also discussed.

Exploring breath biomarkers in BLM-induced pulmonary fibrosis mice with associative ionization time-of-flight mass spectrometry

Pulmonary fibrosis (PF) is a common but fatal disease that threatens human health worldwide. Developing effective diagnostic methods is of great importance for the early detection of PF in patients. In this study, bleomycin (BLM) was used in mice to mimic idiopathic pulmonary fibrosis (IPF). The exhaled breath of BLM-induced PF, PF plus DDAH1 overexpression, and healthy control mice were analyzed in real-time using a newly developed associative ionization time-of-flight mass spectrometry method (AI-TOFMS), which is uniquely sensitive, especially to oxygenated volatile organic compounds (VOCs). Multivariate data analyses and discriminant modeling analyses revealed that four exhaled compounds, i.e., acrolein, ethanol, nitric oxide, and ammonia, had a strong correlation with PF symptoms. An Orthogonal Partial Least Square Discriminant Analysis (OPLS-DA) score plot showed an excellent separation between these three groups. The area under the receiver operating characteristic (ROC) curve for these four compounds distinguished PF mice from healthy controls at 0.989. In addition, the degrees of acute inflammation and fibrosis were assessed with Hematoxylin and Eosin (H&E) staining and Masson's Trichrome staining. Finally, combined with pathological characteristics and mRNA expression levels, the formation of the above-mentioned volatile compounds was explored. The obtained experimental results indicated that these four breath compounds, acrolein, ethanol, nitric oxide, and ammonia, were potential exhaled biomarkers for pulmonary fibrosis.

Bleomycin-induced trans lipid formation in cell membranes and in liposome models

Bleomycin–iron complexes cause lipidcis–transisomerisation through thiyl radical formation and reactivity with unsaturated phospholipids, revealing membranes as a relevant and novel site of drug effect.

Reduction of bleomycin-induced acute DNA injury in the rat lung by the 21-aminosteroid, U-74389G

OBJECTIVE

To determine whether pretreatment with a 21-aminosteroid, U-74389G, can prevent subsequent DNA injury in bleomycin-exposed lungs.

SUBJECTS

Thirty-six adult male Sprague-Dawley rats.

DESIGN

Controlled animal laboratory investigation of DNA injury in vivo.

INTERVENTIONS

Animals were treated with 21-aminosteroid (10 mg/kg) or vehicle and subsequently received intratracheal instillation of bleomycin (1.75 U) or normal saline.

MEASUREMENTS AND MAIN RESULTS

Twenty-four hours after bleomycin exposure, the 21-aminosteroid-treated animals had decreased evidence of DNA injury, expressed as percentage of DNA fragmentation normalized to the control group (113.5 +/- 6 [SEM] vs. 132 +/- 3.9%, p < or = .05), and activity of the DNA repair enzyme poly ADP-ribose synthetase (3.4 +/- 0.2 vs. 5.6 +/- 0.9 pmol nicotinamide adenine dinucleotide/min/mg protein, p < or = .05). Only bleomycin-exposed (+ vehicle) animals demonstrated significant evidence of increased DNA injury vs. the intratracheal saline-exposed control groups.

CONCLUSIONS

The 21-aminosteroid pretreatment decreases subsequent pulmonary DNA injury induced by bleomycin exposure. This finding is likely due to the 21-aminosteroid's iron-chelating and cell-permeating abilities, and suggests that these agents may be effective in other diseases where iron-dependent free radical reactions occur.

Effects of intratracheal administration of bleomycin on GSH-shuttle enzymes, catalase, lipid peroxidation, and collagen content in the lungs of hamsters

Intratracheal administration of one unit of bleomycin increased significantly the glucose-6-phosphate dehydrogenase activity to 147, 135, 163, 207, 278, and 148% of the control at 1, 2, 4, 7, 14, and 21 days post-treatment, respectively. The glutathione peroxidase activity was significantly increased to 147 and 124% of the control at 7 and 14 days post-treatment, respectively. The glutathione reductase and catalase activities were significantly elevated to 132, 174, and 145% of the control in the former and 160, 213, and 160% of the control in the latter case at 7, 14, and 21 days post-treatment, respectively. The amount of thiobarbituric acid reacting products as an index of lipid peroxidation was found to be significantly increased to 251, 248, and 253% of the control at 4, 7, and 14 days after treatment, respectively. The amount of total lung collagen in treated hamsters was significantly increased to 140, 197, and 245% of the control at 7, 14, and 21 days post-treatment, respectively. These findings indicate that the increases in the activities of antioxidant enzymes in lungs of bleomycin-treated hamsters result from the multiple cyto-dynamic events such as infiltration of inflammatory cells, and reparative and proliferative processes which generally follow lung injury caused by any oxidant.