Analysis of the effects of xenobiotic free radicals on aging by using ESR microscopy technique.

在本课题中，我们利用体内低频电子自旋共振(ESR)谱研究了几种药物产生的异种自由基对小鼠衰老的影响。(1)利用体内电子自旋共振(ESR)自旋捕捉技术，检测了联氨和苯肼对大鼠体内5，5-二甲基-1-吡咯啉-N-氧化物(DMPO)/血红蛋白硫基自由基的形成。利用L波段电子自旋共振波谱仪观察到六条线强固定的大鼠血红蛋白硫基自由基的ESR波谱。(2)NO合酶产生的一氧化氮(NO)的无创检测：我们利用L波段微波频率的ESR监测的水溶性金属络合物N-甲基-D-葡糖胺二硫代氨基甲酸酯(MGD)和Fe(II)，进行了体内NO的直接、实时检测。产物[(MgD)_2-Fe(II)-NO]在脂多糖(LPS)处理的小鼠体内无创地获得了三条线的ESR谱。在注射脂多糖之前，苯基N-叔丁基硝酮(PBN)是一种诱导型一氧化氮合酶的表达抑制剂，显著抑制了光谱。(3)体内几个部位(从头到尾)的ESR测量表明，NO主要在靠近肝脏的上腹部产生。在肝脏中检测到的NO复合体的最大浓度约为100µM。

Although the existence of free radicals in drug metabolites can be inferred from end product analysis in our modern environment, no study on the effects of these xenobiotic free radicals on aging has been carried out.In this project, we have studied the effects of xenobiotic free radicals generated from several drugs on aging of mice using low-frequency in vivo electron spin resonance (ESR) spectroscopy.(1) We have employed the ESR spin trapping technique in vivo to detect the formation of the 5,5-dimethyl-1-pyrroline-N-oxide (DMPO)/hemoglobin thiyl free radical in rats following administration of either hydrazine or phenylhydrazine. Six line, strongly immobilized ESR spectra of hemoglobin thiyl radicals were observed in rats by L-band ESR spectrometer.(2) Non-invasive detection of nitric oxide (NO) which is generated by induced NO synthase : We have carried out direct, real-time, in vivo measurement of NO in mice using the water soluble metal chelator complex, N-methyl-D-glucamine dithiocarbamate (MGD), and Fe (II) as monitored by ESR at L-band microwave frequency. The three-line ESR spectrum from the product [(MGD)_2-Fe (II)-NO] was obtained non-invasively in lipopolysaccharide (LPS)-treated mice. The spectrum was markedly suppressed by the administration, prior to LPS injection, of phenyl N-tert-butyl nitrone (PBN), an inhibitor of the expression of induced no synthase.(3) In vivo ESR measurements of [(MGD)_2-Fe (II)-NO] at several regions in the body (from the head to the tail) indicated that the NO was generated mostly in the upper abdomen near the liver. The concentration of NO complex detected in the liver was about 100 mu M at maximum.