The inhibitory effect of PNS on brain 3-NT formation in vitro

XIAO Chen; SUN Li; CAO Shan-shan; LIANG Hao; CHENG Yan

doi:10.11958/20161334

Abstract：Objective To study the inhibitory effect of panax notoginseng saponins (PNS) on 3-nitrotyrosine (3-NT) formation in brain induced by heme/NO2 -/H2O2 or ONOO - pathways in vitro. Methods According to the two major pathways of 3-NT formation in vivo, the models of protein nitration induced by heme/NaNO2/H2O2 or ONOO-system were established, respectively, in vitro. Bovine serum albumin (BSA)/rat plasma protein or rat brain homogenate protein were utilized as reactive substrates in both systems. Samples were divided into blank-control group, 3-NT group and PNS group (including low-, medium-and high-concentration subgroups). In 3-NT group, samples were exposed to heme/NaNO2/H2O2 or ONOO-system, respectively, at 37℃for 30 min, whereas in PNS group, samples were pre-incubated with PNS (at final concentrations of 50 mg/L, 100 mg/L, and 200 mg/L) at 37℃for 5 min before the nitrating system exposure. The 3-NT level in each group was detected by Western blot assy. Results Compared with the blank-control group, both heme/NaNO2/H2O2 and ONOO-system can induce significant 3-NT generation in BSA/rat plasma protein or rat brain homogenate protein (P<0.05). Compared with model group, PNS pre-treatment markedly inhibited 3-NT expression in BSA/rat plasma protein in a dose-dependent manner (P<0.05), the inhibitory effect of low intervention on the level of 3-NT in rat brain homogenate protein was not significant (P>0.05). Medium- and high-concentrations of PNS pre-treatment markedly inhibited 3-NT accumulation, with maximum effect at the concentration of 200 mg/L (P<0.05). Conclusion Medium- and high-concentrations of PNS can inhibit 3-NT formation in brain tissue mediated by either heme/NO2-/H2O2 or ONOO-pathways, implying that potential neuroprotective action against 3-NT involves pathological conditions, like trauma, stroke, and neurodegenerative diseases.