Mechanisms by Which Physical Activity Modulates the Wnt/β-catenin Pathway to Alleviate Anxiety-like Depression

Abstract

This study aimed to explore the effect of treadmill exercise on anxiety in rats. Thirty SPF male rats aged 2 months with a body mass of (225±25) g were randomly divided into control group (CG, n=10), chronic sleep deprivation group (CSD, n=10) and sleep deprivation exercise group (CSD+E, n=10) after adaptive feeding for 1 week. The CSD model of rats in CSD group and CSD+E group was made by multi platform water environment method. Sleep deprivation of 18 h per day (from 12:00 pm. to 6:00 am. the next day) for 8 weeks. The effect of running on the anxiety-like behaviour of CSD rats was examined in the open field test (OFT) and the elevated plus maze (EPM) experiment. Hematoxylin-eosin (HE) staining, Annexin V/PI flow cytometry, immunofluorescence staining, Western blot, RT-qPCR and other methods were used to detect the effects of treadmill exercise on the morphology of hippocampus, apoptosis related factors caspase-12, Bax, Bcl-1, inflammatory factors (IL-6, TNF-a), Wnt β- catenin, p- β-catenin. The results of HE staining showed that the brain tissue of the control rats was structurally intact, with thick layers of cone cells, relatively dense, neatly arranged and compact, the cell edge structures were intact and clearly visible, with no obvious abnormal changes. The cone cell layer of brain tissue in the chronic sleep deprivation group was thin, with relatively low cell density, disorganized and sparse arrangement, and blurred cell edges. The symptoms of the above pathological changes in brain tissue of rats in sleep deprivation exercise group gradually alleviated. OFT results showed that compared with CG group, the number of activities in the central region of CSD group was significantly reduced (P<0.01), and the total distance of exercise was significantly shortened (P<0.01). EPM results showed that compared with CG group, OT and CE in CSD group decreased significantly (P<0.01). CCK-8 results showed that compared with CG group, the activity of neurons in CA1 area of hippocampus in CSD group was significantly decreased (P<0.01), while that in CSD+E group was significantly increased (P<0.01); Annexin V/PI flow cytometry results showed that compared with CG group, the apoptosis of neurons in CA1 area of hippocampus in CSD group increased (P<0.01), and that in CSD+E group decreased significantly (P<0.01);Western blot results showed that caspase-12, Bax, IL-6, IL-1β and TNF-a were highly expressed and Bcl-1 was lowly expressed in hippocampal tissues of rats in the CSD group compared with the CG group (P<0.01), Wnt, β-catenin and p-β-catenin were lowly expressed in hippocampal tissues of rats in the CSD group, and Gsk-3βprotein expression was significantly higher (p<0.01). The results of RT-qPCR showed that caspase-12 mRNA, Bax mRNA, IL-6 mRNA, TNF-a mRNA and IL-1β mRNA were highly expressed and Bcl-1 mRNA was lowly expressed in hippocampal tissues of rats in the CSD group compared with the CG group (P<0.01). Compared with the CG group, Wnt mRNA and β-catenin mRNA were significantly lowly expressed and Gsk-3βmRNA was significantly highly expressed in hippocampal tissue of CSD rats (P<0.01). Our findings indicated that 8 weeks of aerobic exercise significantly improved anxiety-like depression in CSD rats by increasing neuronal activity, inhibiting apoptosis, reducing the inflammatory response and activating the Wnt/β-catenin pathway.