Abstract:

Objective

To investigate the protective effect of curcumol against apoptosis and its mechanism of action on cortical cells after post-traumatic stress disorder （PTSD） in rats.

Methods

Twelve healthy male SD rats were divided into blank control group， SPS group and curcumin group according to the randomized numerical table method， and the curcumin group was divided into a low concentration group （2.0 mg/kg） and a high concentration group （4.0 mg/kg） according to different concentrations， with three rats in each group. The SPS group and the curcumol group were subjected to single prolonged stress to establish the SPS model， and the conditioned fear test for the fearfulness of the rats was performed on the 7^th day. The curcumol group was injected continuously intraperitoneally［2.0 and 4.0 mg/（kg·d）］ 7 d after SPS modeling， while the SPS group was only intraperitoneally injected with physiological saline， the control group did not receive any treatment. Cerebral cortex tissue specimens were collected from rats after execution. Western blotting was used to detect the effects of drug intervention on the protein expression levels of phosphorylation of the eukaryotic initiation factor 2 （p-eif2a）， the eukaryotic initiation factor 2 （eif2a）， C/EBP-homologous protein （CHOP）， and β-actin； Use an enzyme-linked immunosorbent assay kit to detect changes in the expression levels of inflammatory factors interleukin （IL）-1β， IL-6， and tumor necrosis factor α （TNF-α）； TUNEL cell apoptosis staining was used to detect the apoptosis of cells in the medial prefrontal cortex of rats；Pharmacotoxicity of curcumol on neuroglia was detected by live-dead cell staining and flow cytometry.

Results

After 7 d of SPS modelling， the results of the conditional fear box test showed that the freezing time percentage of the SPS group rats was significantly higher than that of the control group， and the freezing time percentage of curcumin group was significantly lower than that of the SPS group， with statistical significance （P＜0.05）. The Western blotting results showed that the levels of p-eif2a and CHOP proteins in the SPS group were significantly higher than those in the control group， while the levels of p-eif2a and CHOP proteins in the low concentration and high concentration groups of curcumin were significantly lower than those in the SPS group， with statistical significance （P＜0.05）. The ELISA detection results showed that the levels of IL-1β， IL-6， and TNF-α in the SPS group were significantly increased compared to the control group， while the levels of IL-1β， IL-6， and TNF-α in the high concentration group of curcumin were significantly decreased compared to the SPS group， with statistical significance （P＜0.05）. The apoptosis rate of cells in the SPS group was significantly higher than that in the control group， while the apoptosis rate of cells in the high concentration group of curcumin was significantly lower than that in the SPS group， and the differences were statistically significant （P＜0.05）.CCK-8 detection showed that after co culturing with 2 μg/mL curcumin solution for 0， 3， 6， 12， and 24 h，there was no significant change in the activity of microglia at each time point， and no obvious dead cells were observed.

Conclusions

Curcumol was able to inhibit the fear freezing state in rats after PTSD，exerting neuroprotective effects and inhibiting neuroinflammation， and its mechanism of action may be related to the inhibition of the expression of the eif2a-CHOP endoplasmic reticulum stress pathway and the inhibition of apoptosis by curcumol.

Key words: Post-traumatic stress disorder, Curcumol, Apoptotic, Endoplasmic reticulum stress