Introduction:
This study aimed to investigate the preventive and therapeutic effects of crocetin (Cro) on ischaemic stroke in cell and animal models.

Material and methods:
A cell model of oxygen and glucose deprivation (OGD) and a rat model of middle cerebral artery occlusion were established to simulate ischaemic stroke. The infarct volume was measured by TTC assay, and the apoptotic cell number was counted by TUNEL. Relative protein and gene expression levels in the rats were measured by immunohistochemical and RT-qPCR assays. The apoptosis rate and relative protein and gene expression levels were determined by flow cytometry, WB and RT-qPCR assay, respectively.

Results:
Compared with those in the normal control (NC) group, the brain tissue injury and apoptotic cell number significantly increased (p < 0.001) and the miR-145-5p gene expression significantly decreased in the cell and animal experiments. In the animal experiment, the infarct volume, apoptotic cell number and pathological status improved in the Cro-treated groups. In the cell experiment, the apoptosis rates significantly depressed in the Cro-treated groups (p < 0.05). However, the cell apoptosis rate significantly increased after miR-145-5p inhibitor transfection (p < 0.001). The protein and gene expression levels of Toll-like receptor 4, myeloid differentiation factor 88 and nuclear factor (NF)-κB (p65) significantly decreased (p < 0.05). In addition, p-NF-κB(p65) nuclear volume significantly decreased (p < 0.05).

Conclusions:
Crocetin improved ischaemic stroke by regulating the miR145-5p/TLR4 axis in cell and animal experiments.