DMPO (5,5-dimethyl-1-pyrroline-N-oxide) is a water-soluble nitric oxide spin trap that can be used to measure oxygen-centered free radicals in biological systems at room temperature using electron spin resonance (ESR) [1]. The spin trap reacts with free radicals to form stable adducts that can be further studied [2]. DMPO is water-soluble, rapidly permeates lipid bilayers, has low toxicity, and can be used in vitro and in vivo [3, 4].
In vitro, DMPO (50 mM) treatment of RAW 264.7 macrophages for 24 h showed anti-inflammatory activity, reduced inducible nitric oxide synthase (iNOS) expression, inhibited the phosphorylation of MAPK, Akt and IκBα, and reduced NF-κB p65 translocation[5].
In vivo, DMPO (10-100 mg/kg, intraperitoneal injection) had an analgesic effect on formalin-induced hyperalgesia in rats[6].
References:
[1] Wang P, Zweier J L. Measurement of nitric oxide and peroxynitrite generation in the postischemic heart: evidence for peroxynitrite-mediated reperfusion injury[J]. Journal of Biological Chemistry, 1996, 271(46): 29223-29230.
[2] Bačić G, Spasojević I, Šećerov B, et al. Spin-trapping of oxygen free radicals in chemical and biological systems: new traps, radicals and possibilities[J]. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2008, 69(5): 1354-1366.
[3]West M B, Rokosh G, Obal D, et al. Cardiac myocyte–specific expression of inducible nitric oxide synthase protects against ischemia/reperfusion injury by preventing mitochondrial permeability transition[J]. Circulation, 2008, 118(19): 1970-1978.
[4]Qin X, Wu C, Niu D, et al. Peroxisome inspired hybrid enzyme nanogels for chemodynamic and photodynamic therapy[J]. Nature Communications, 2021, 12(1): 5243.
[5]Zhai Z, Gomez-Mejiba S E, Zhu H, et al. The spin trap 5, 5-dimethyl-1-pyrroline N-oxide inhibits lipopolysaccharide-induced inflammatory response in RAW 264.7 cells[J]. Life sciences, 2012, 90(11-12): 432-439.
[6]Chung W S, Go Y G, Lee W H. Antinociceptive effect of intraperitoneally administered 5, 5-dimethyl-1-pyrroline N-oxide on formalin induced nociception in rats[J]. Korean J Anesthesiol, 2008, 54(3).
DMPO（5,5-二甲基-1-吡咯啉-N-氧化物）是一种水溶性一氧化氮自旋捕获剂，可利用电子自旋共振（ESR）在室温下测量生物系统中以氧为中心的自由基[1]。自旋捕获剂与自由基反应，形成可进一步研究的稳定加合物[2]。DMPO是水溶性的，快速渗透脂质双层，毒性低，可在体外和体内使用[3, 4]。
在体外，DMPO（50 mM）处理RAW 264.7巨噬细胞24h，显示出抗炎活性，降低了诱导型一氧化氮合酶（iNOS）表达，抑制了MAPK、Akt和IκBα的磷酸化，并减少NF-κB p65易位[5]。
在体内，DMPO（10-100 mg/kg，腹腔注射）对福尔马林诱导的痛觉过敏大鼠具有镇痛作用[6]。