Perillaldehyde pretreatment alleviates cerebral ischemia-reperfusion injury by improving mitochondrial structure and function via the Nrf2/Keap1/Trx2 axis

Background: Perilladehyde, an extract of perillae in the Labiatae family, can produce significant anti-inflammatory and antioxidant effects. Although literature evidences the favorable effect of perillaldehyde on ischemic stroke, the exact mechanism remains blurred.

Purpose: This study attempted to explore the impact of perillaldehyde on cerebral ischemia-reperfusion injury and the related action mechanism.

Methods: The rat tMCAO and neuronal OGD/R models were established to simulate cerebral ischemia-reperfusion injury. Lentiviruses were used to interfere with the expression of Nrf2 and Trx2 in neurons. The effects and action mechanisms of perillaldehyde were explored by various experimental methods, including chromatin immunoprecipitation assay, Western Blot, flow cytometry, dual-luciferase reporter gene assay, transmission electron microscopy, MRI, RNA-seq, and immunofluorescence staining.

Results: Perillaldehyde pretreatment effectively mitigated the tMCAO-induced brain injury in rats by reducing cerebral infarction, improving neuromotor function, and attenuating cell apoptosis in the ischemic penumbra. In vitro, perillaldehyde pretreatment alleviated cell death and excessive oxidative stress, preserved the mitochondrial membrane integrity, enhanced mitochondrial energy metabolism, and facilitated the restoration of mitochondrial ultrastructure after OGD/R. The mechanism probe revealed that perillaldehyde activated the Nrf2/Keap1/Trx2 signaling axis, thus promoting the transcription of Trx2 and improving mitochondrial structure and function. The aforementioned impacts of perillaldehyde were somewhat counteracted by disrupting the expression of Nrf2 and Trx2, suggesting that the neuroprotection of perillaldehyde partially involves the activation of the Nrf2/Keap1/Trx2 axis.

Conclusions: This study firstly demonstrates the existence of the Nrf2/Keap1/Trx2 signaling axis in cerebral ischemia-reperfusion injury and evidences that perillaldehyde pretreatment can promote the restoration of neuronal mitochondrial structure and function by activating the Nrf2/Keap1/Trx2 axis after cerebral ischemia-reperfusion injury. These findings signify that perillaldehyde holds great promises for clinical management of ischemic stroke.