β-caryophyllene alleviates ischemic stroke injury by upregulating neuronal miR-183 expression in mice

Abstract

Objective To investigate the protective effect of β-caryophyllene (BCP) against ischemic stroke injury in mice and clarify whether such protective effects are associated with miR-183 and nuclear factor-κB (NF-κB) expression. Methods Ninety male C57BL/6 mice were randomized equally into 3 groups, namely the sham-operated group, ischemia-reperfusion (I/R) model group, and BCP (72 mg/kg) pretreatment group. The mice in the latter 2 groups were subjected to middle cerebral artery occlusion for 60 min followed by reperfusion for 24 h. The neurological deficits and infarct volume of the mice were measured, and the pathological changes in the brain tissues were observed using HE and Nissl staining. The expression of miR-183, NF-κB, p-NF-κB, interleukin-1β (IL-1β), and IL-6 in the brain were detected, and the targeting relationship between miR-183 and NF-κB was determined. In the in vitro experiment, the cortical neurons isolated from the brain of neonatal mice were divided into normal group, oxygen-glucose deprivation (OGD) group, and OGD group with 10 μmol/L BCP pretreatment. Immunofluorescence assay was employed for morphological observation of the neurons, and the cell injury was assessed with lactate dehydrogenase (LDH) leakage assay. The expression levels of miR-183, IL-1β, IL-6 and NF-κB in the neurons were measured. Results In the mouse models of ischemic stroke, BCP pretreatment significantly improved neurologic deficit score, reduced the infarct volume, lessened pathological changes of the brain tissue, and decreased the number of Nissl-positive cells in the cortex (P < 0.05). BCP pretreatment significantly upregulated the expression of miR-183 in the brain tissues of the mice (P < 0.05). In the in vitro experiment, BCP pretreatment produced obvious protective effect on neurons and significantly lowered neuronal death rate following OGD (P < 0.05). BCP treatment significantly upregulated the expression of miR-183, inhibited NF-κB activation and lowered the expressions of inflammatory factors in the neurons (P < 0.05). Conclusion BCP protects the brain tissues against ischemic stroke injury by upregulating the expression of miR-183, which inhibits NF-κB activation and lowers the release of inflammatory factors to alleviate inflammation in the brain.

Keywords

• β-caryophyllene
• mir-183
• ischemic stroke
• nuclear factor-κb