The main finding of this study is that RMT and n-3 PUFAs synergistically reverses oxidative and neuro-inflammatory pathophysiology and protects the neuronal cells from further oxidative stress damage. To our knowledge, this is the first report to demonstrate the underlying synergistic mechanism of RMT and n-3 PUFAs EPA and DHA counter acting by preventing and rescuing the neurons from the pathogenic effect of oxidative stress.
Consistent with the previous studies 51,52, cell viability of SH-SY5Y cells was likely not affected with lower concentrations of H2O2; on the other hand, high-level H2O2 initiated cell death. In addition, our finding from the cell viability assay infers significant synergism existing between RMT and EPA by stimulating viability and providing an additional insight on their preventive and therapeutic effects. Several studies ascertain the specific mode of action of EPA promoting neuronal survival, which further supports our finding 53-55. Interestingly, the present data also shows that DHA in combination with FLX were able to improve the viability in the rescue group through inhibition of apoptosis. DHA treatment is found to be differentially affecting the viability with different cell lines 56-58. Previous studies have shown protective actions of DHA 59-61 and FLX 62,63 against neuronal injury by various mechanisms supporting our results.
Generally, the fate of the neuronal cells, directly and indirectly, is modulated by the accumulation of ROS during oxidative stress. In our study, a significant decrease in ROS was observed with the cells pretreated with RMT and EPA demonstrates their ROS inhibitory effect. This initial blockage of ROS generation might offer significant protection of neurons by RMT and EPA indicates their anti-inflammatory and anti-oxidative effects. Interestingly, DHA showed ROS inhibiting effect with the rescue group which may elucidate its neuroprotective nature. However, we still do not know precisely the therapeutic dynamics of RMT and n-3 PUFAs integrated into ROS inhibition involved in cell survival. On the other hand, an increased ROS level was seen with H2O2 pretreatment followed by FLX and with combination of n-3 PUFAs, needs further experiments to investigate this paradoxical effect.