Targeted metabolomics of neurotransmitters and tryptophan reveal neuroprotective effect of Dl-3-n-butylphthalide in cerebral ischemia-reperfusion mice

BACKGROUND: To explore the effect of Dl-3-n-butylphthalide (NBP) on metabolite profiles of neurotransmitters and tryptophan using a mouse model of cerebral ischemia-reperfusion (I/R). MATERIALS AND METHODS: Cerebral I/R was induced by occlusion of the middle cerebral artery in the mouse model. Mice were allocated into three groups: Sham, I/R + Saline (Saline) and I/R + NBP (NBP). Liquid chromatography with tandem mass spectrometry-based targeted metabolomics were employed to detect differential metabolites of neurotransmitters and tryptophan in cerebral tissue and plasma across three groups. RESULTS: The NBP group exhibited significantly improved neurological function. By screening the overlapping differential metabolites between the saline versus sham groups and NBP versus saline groups, we have identified four differential metabolites of neurotransmitters. Specifically, glutamine, 3,4-dihydroxyphenylacetic acid (DOPAC), and homogentisic acid (HGA) were detected in the plasma of sham group but were absent in saline group. Treatment of NBP, however, led to a marked elevation of these three metabolites in plasma relative to saline group. In comparison with sham group, saline group exhibited an upregulation of Xanthurenic acid (XA) in plasma, yet were markedly suppressed following NBP treatment. Additionally, targeted metabolomics of tryptophan metabolites revealed the consistent trend in XA plasma levels across three groups. These observations imply that the neuroprotective action of NBP could be mediated through its influence on the concentrations of these critical metabolites. CONCLUSION: NBP significantly upregulated the levels of glutamine, DOPAC, and HGA in plasma while downregulating the level of XA in cerebral I/R mice, providing novel insights into the neuroprotective mechanisms of NBP.