Investigation Of Methods For Measuring Redox State In Body Fluid And The Determination Of Normal Range Of Redox State In Healthy People

The body needs a relatively constant redox status, as the way that a relatively constant balanced pH value is needed. Any shifting of such equilibrium would lead to damages of the system. But whether there is a justified index reflecting redox status, and a normal value range within healthy people are of importance in the field of homeostasis of body fluid.Methods: 200 healthy male and female blood samples, with different age groups, were collected. Oxidized and reduced glutathion, oxidized and reduced coenzyme II and apparent redox potential were measured to determine the ideal indices reflecting redox status of body fluid including serum, plasma and red blood cell lysis fluid. The purpose of this work was to determine: (1) what kind of redox item would accurately reflect redox status; (2) what was the most proper body fluid for determination; (3)what was the normal range of redox status in healthy people; (4)was there any impact of age or sex on normal range on redox status.Results: 1. among the three kinds of body fluid, plasma is the best sample for GSH/GSSG determination; while NADPH/NADP~+ should be measured in serum, and apparent potential better be determined in frozen-thawed serum. 2. there were no differences in redox status between sexes, while the comparison between young adults and old adults showed significantdifferences.3. the normal range of redox status of young adults with average age of 20.4±0.8ys was that:glutathion and glutathione disulfide in plasma :GSH concentration: 8.67 ± 1.9 u mol/L GSSG concentration: 0.08+0.39 u mol/LGSH/GSSG ratio: 8.72+2.53 GSH/GSSG potential: -216.92 + 3.94mV Coenzyme II in serum :NADPH concentration : 77.25 +4.46nmol/LNADP+ concentration: 3.73 ± 1.07nmol/LNADPH/NADP+ ratio: 22.56± 5.59NADPH/NADP+potential: -282.19 + 3.08mV Apparent potential in frozen-thaw serum: 90~ 120mV(l 05.06 + 13.73mV) 4. the normal range of redox status of old adults with average age of 57.6 ± 10.9ys was that: glutathion and glutathione disulfide in plasma :GSH concentration: 7.28 + 0.80 u mol/L; GSSG concentration: 1.19 ± 0.19 u mol/LGSH/GSSG ratio: 6.26 + 1.19 GSH/GSSG potential: -211.15 + 3.28mV Coenzyme II in serum :NADPH concentration : 60.73 ± 4.25nmoI/L NADP+ concentration: 6.26 ±1.19 nmol/L NADPH/NADP+ratio: 11.29 + 1.38 NADPH/NADP+potential: -265.66+6.51mVApparent potential in frozen-thawed serum: 105~135mV(120.85± 15.79) 5. The result of GSH/GSSG and NADPH/NADP+ showed a reduced status of healthy people under normal condition. The value of GSH/GSSG and NADPH/NADP+ was relatively stable in the healthy people and displayed normal distribution, and in consistent with the rule that electron is passed fromNADPH to GSSG. Correlation between GSH/GSSG and NADPH/NADP+ value was showed linear.6. The tendency of serum apparent potential increasing with age was in accordance with GSH/GSSG and NADPH/NADP+ results. However, the apparent potential value was positive, which need further study of its ability to reflect the redox status.Conclusion: 1: Serum and plasma were both suitable samples to measure the redox status. But the determination of GSH/GSSG was suggested to use plasma sample, while for NADPH/NADP+, serum sample was better than plasma sample.2. GSH/GSSG ratio and GSH/GSSG redox potential, NADPH/NADP+ ratio and NADPH/NADP+ redox potential were the ideal indices to observe the redox status. They showed an accurate reduced state of redox status under normal condition in healthy person, and they had significant correlation, too. Therefore, these items should be the ideal indices to reflect the redox status.3. The normal range of GSH/GSSG and NADPH/NADP+ in healthy people was determined. The normal range showed differenc with age, but there was no difference between sexes.4. the redox status of the aged shifted toward oxidative state, especially the NADPH/NADP+ ratio and NADPH/NADP+ redox potential, shifted much more, which suggested that the relationship of aging and redox imbalance.5. Serum apparent potential was positive. The serum potential from the aged increased 15% compared with young adults. The tendency of serum apparent potential increasing with age was in accordance with GSH/GSSG and NADPH/NADP+ results. However, the apparent potential value was positive, which was much more oxidized comparison GSH/GSSG potential and NADPH/NADP"1" potential. This needs further study of its ability to reflect the systemic redox status.