3.1 SARS-CoV-2 induces changes in oxidative stress markers in blood samples of COVID-19 patients.
Different markers of oxidative damage, including hydrogen peroxide and nitric oxide formation and also some major toxic side effect were analyzed such as protein carbonyl levels, were determined in the plasma of COVID-19-patients. The amount of H2O2was assessed as an index of oxidative stress total, are shown in Fig. 1A. In control patients, baseline H2O2levels was 712.7 ± 186.2 ng/mL, while in plasma from COVID-19-patients there were less increases in H2O2formation of 28.9% in the viremia group and significant increases of 46.4% in the MODS group (p<0.05), above control (919.3±151.6 and 1044±125.4; respectively). On the other hand, the peroxide levels in the non-positive MODS COVID-19 group were similar to the control group (11% above control).
In regard to NO production are shown in Fig. 1B, baseline levels in control group were found around 34.91± 4.463 µmol of NO2/mg protein. The COVID-19-induced increases in nitrites accumulation were found around 370 % in viremia (p<0.01) and 216 % in sepsis whit MODS (p<0.05), above control (164.2± 12.60 and 110.4± 13.39; respectively). In addition, non-positive MODS COVID-19 group showing higher levels of nitric oxide (p<0.01).
The levels of protein oxidation (expressed as the formation of protein carbonyl as a marker of proteostasis-loss) from all experimental groups are shown in Fig. 1C. Basal levels were 3.238±0.2746 nmol/mg protein. COVID-19 produced changes in protein carbonyl when compared with control group values at any of all times tested in 61.8% in the viremia group and 102% in the MODS group; statistical significance was set at p<0.05 (5.240±0.4537) and p<0.01 (6.542±0.3925) respectively. The MODS not COVID-19 group, showed the highest protein carbonyl levels (p<0.01). Whereas Fig. 1D presents the correlation between peroxide levels and proteins carbonyl content found in blood of COVID-19-patients. Noteworthy a correlation between parameters was found of r = 0.88