pachymic-acid and Brain-Ischemia

Pachymic acid (PA) plays a neuroprotective role during cerebral ischemia/reperfusion. However, the protective mechanisms of PA in cerebral ischemia/reperfusion have been not fully determined. This investigation aims to explore the neuroprotective role of PA in ischemia/reperfusion via miR‑155/NRF2/HO‑1 axis. The N2a cell line was induced by hypoxia/reoxygenation (H/R) to simulate the neuronal damage that occurs during cerebral ischemia/reperfusion. PA was used to treat H/R‑induced N2a cells. An MTT assay was used to determine cell viability. The protein levels of Bcl‑2, Bax, heme oxygenase‑1 (HO‑1) and nuclear factor E2‑related factor 2 (NRF2) were measured via Western blot analysis. The level of apoptosis of N2a cells was determined by flow cytometry. The expression levels of miR‑155 and NRF2 were quantified by real‑time PCR. PA treatment inhibits the increase in apoptosis induced by H/R and also enhances the viability of cells exposed to H/R. PA reverses the increased expression of miR‑155 caused by H/R. Furthermore, H/R does not change the expression of HO‑1 and NRF2, but PA upregulates the expressions of HO‑1 and NRF2. Additionally, NRF2 is the target of miR‑155. Inhibiting miR‑155 contributes to increased cell viability and decreased apoptosis via targeting the NRF2/HO‑1 pathway. Overall, PA prevents neuronal cell damage induced by hypoxia/reoxygenation via miR‑155/NRF2/HO‑1 axis.

Topics: Apoptosis; Brain Ischemia; Heme Oxygenase-1; Humans; Hypoxia; MicroRNAs; NF-E2-Related Factor 2; Oxidative Stress; Signal Transduction; Triterpenes

Pachymic acid (PA) from medicinal fungus Poria cocos has a variety of pharmacological potentials. However, there are no reports of the effects of PA on cerebral ischemia/reperfusion (I/R) injury. The purpose of this study was to investigate the mechanisms of PA on cerebral I/R injury in rats. The effects of PA on cerebral infarction size, brain water content, neurological symptoms and cerebral blood flow were evaluated. Nissl staining was used to observe the damage of ischemic brain neurons after I/R in rats. Apoptosis of ischemic brain neurons after I/R was observed by TUNEL staining. The effect of PA on the expression of some components of PI3K/Akt was detected by Western blotting. PA significantly increased cerebral blood flow after I/R in rats, reduced infarct volume and brain water content, and downgrade neurological function scores, significantly reduced neuronal damage after I/R in rats, and significantly decreased neuronal apoptosis. The effect of PA on rat I/R can be eliminated by LY294002. In addition, PA significantly up-regulated the protein expression of p-PTEN (Ser380), p-PDK1 (Ser241), p-Akt (Ser473), pc-Raf (Ser259) and p-BAD (Ser136), and down-regulated Cleaved caspase protein expression. LY294002 can reverse the effect of PA on the expression of PI3K / Akt signaling pathway related protein in rats after I/R. PA had obviously neuroprotective effects on brain I/R injury and neuronal apoptosis, and its mechanism may be related to activation of PI3K / Akt signaling pathway.

Topics: Animals; Apoptosis; Brain Ischemia; Male; Neurons; Neuroprotective Agents; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Signal Transduction; Triterpenes