Lipid peroxidation of mitochondrial membrane induced by D1: an organic solvent extractable component isolated from a crude extract of burn eschar.
D1, an organic solvent extractable component of an extract from burn eschar was characterized and the mechanism of its inhibitory effect on mitochondrial respiratory functions was investigated. Using silicic acid column chromatography, it was found that D1 consisted of two parts: a toxic simple lipid and a non-toxic complex lipid. Six subunits were obtained by further silicic acid column chromatography, among them, the no. 4 and no. 6 were toxic. Infrared spectrometric studies showed that no. 4 consisted of esters, while no. 6 were peroxides. D1 also contained large amounts of malonaldehyde (MDA) and lipid hydroperoxides (ROOH). Vitamin E was found to prevent the inhibitory action of D1 on mitochondrial function and to reduce the amount of MDA produced. However, if vitamin E was introduced after the addition of D1 the inhibition could not be prevented, although there was still a reduction in MDA production; therefore, MDA per se was probably not the cause of the inhibition. D1 induced ROOH formation in mitochondrial membranes. Cumene hydroperoxide, an organic hydroperoxide, was capable of inhibiting the mitochondrial function. This inhibitor action was blocked by vitamin E. It is speculated that ROOH in D1 is probably the element that inhibits mitochondrial function. That D1 caused lipid peroxidation of membrane lipid was also proved by analysing the fatty acid composition of mitochondrial membranes before and after treatment with D1. It was found that the amount of polyunsaturated fatty acids decreased and that of saturated fatty acids increased after incubation with D1, a direct proof that lipid peroxidation has occurred. Lipid peroxidation of the membrane lipid was the result of the action of oxygen free radicals. This process was best shown by a chemiluminescence study. In this experiment, D1 induced chemiluminescence which was dose-dependently related to the amount of D1 used. This was probably the most direct proof that D1 caused lipid peroxidation of membrane lipid resulting in damage of the mitochondria.
Chen
Z
Z
Department of Radiation Medicine, School of Preventive Medicine, Third Military Medical College, PLA, Chongqing, Sichuan, People's Republic of China.
Xiong
Y
Y
Lou
S
S
Shu
C
C
D002056:Burns; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D002845:Chromatography; D002921:Cicatrix / Q000378:metabolism; D046508:Culture Techniques; D004347:Drug Interactions; D006801:Humans; D015227:Lipid Peroxidation / Q000187:drug effects*; D008163:Luminescent Measurements; D008928:Mitochondria / Q000187:drug effects* / Q000378:metabolism; D012997:Solvents / Q000494:pharmacology*; D014810:Vitamin E / Q000494:pharmacology*
D012997:Solvents; D014810:Vitamin E