2003 Fiscal Year Final Research Report Summary
Development for measuring the concentration of hydrogen peroxide in vivo using ESR equipment
| Project/Area Number |
14572044
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Physical pharmacy
|
|---|
| Research Institution | National Institute of Radiological Sciences |
|---|
Principal Investigator |
UEDA Jun-ichi National Institute of Radiological Sciences, Redox Regulation Research Group, Team Leader, 放射線安全研究センター・レドックス制御研究グループ, チームリーダー (90160168)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
TAKESHITA Keizo National Institute of Radiological Sciences, Redox Regulation Research Group, Senior Researcher, 放射線安全研究センター・レドックス制御研究グループ, 主任研究員 (70175438)
|
|---|
| Project Period (FY) |
2002 – 2003
|
| Keywords | hydrogen peroxide / free radical / in vivo ESR / in vitro ESR / L-band / surface-coil-type resonator |
|---|
| Research Abstract |
In order to measure quantitatively the amount of hydrogen peroxide (H_2O_2) generated by phagocytes or irradiation of ionizing radiation in whole body, a cation radical formed by the reaction of H_2O_2 with 2,2-azino-bis(3-ethylbenzthiazoline)-6-sulfonic acid (ABTS) in the presence of peroxidase (HRP) was measured using L-band ESR with surface-coil-type resonator. The amount of H_2O_2 may be related to signal intensity of the ESR spectrum of ABTS cation radical, where H_2O_2 reacts with HRP, resulting in the production of compound I, and then the compound I oxidized ABTS to yield ABTS cation radical.
Liposomes (1.24 mol ABTS/mol phospholipid (DMPC : cholesterol : stearylamine=1:1:0.1)) containing ABTS and HRP (ABTS-HRP-liposome) were prepared. However, the liposomes were not used for further analysis.
A solution of pre-formed ABTS cation radical solution produced by mixing an ABTS-HRP solution with various concentrations of H_2O_2,was intraperitoneally injected into mouse and measured using a L-band ESR spectrometer to elucidate sensitivity of the L-band ESR. The L-band ESR signal of ABTS cation radical was observed in the presence of H_2O_2 more than 2 ? mol, suggesting that the lowest limiting concentration of H_2O_2 is probably 2 ? mol.
On the other hand, the ABTS-HRP solution was intraperitoneally injected into mouse, followed by the injection of a large amount of H_2O_2 into mouse. As a result, the L-band ESR spectrum of ABTS cation radical was obtained. On the contrary, the injection of LPS, which should cause the generation accumulation of phagocytes in the peritoneal cavity, gave no ESR spectrum.
|
