Vitamin D and 17β-estradiol upregulate each other's receptors and regulating the AMPK/NF-κB pathway to relieve depressive-like behaviors in female ovariectomized rats

Abstract Background: A deficiency of vitamin D (VD) or 17β-estradiol (E2) is associated with increased risk of mood disorders such as depression in menopausal females, but the mechanism underlying is still elusive. The present study aims to evaluate whether vitamin D and 17β-estradiol could relieve a depressive-like state through neuroinflammatory regulation in ovariectomized (OVX) rats. Methods: Female SD rats were randomly divided into four groups, namely, control (SHAM), OVX, OVX+VD, and OVX+E2. The treatment procedure was performed for 10 weeks until sacrifice. Results: The chronic administration of vitamin D and 17β-estradiol showed anti-depressive-like activity in the OVX rats. Additionally, vitamin D and 17β-estradiol upregulated each other's receptors, including VDR, ERα, and ERβ in the hippocampus of OVX rats. Vitamin D and 17β-estradiol showed neuroprotective effects by decreasing OVX-induced apoptosis and neuronal damage, regulating the AMPK/NF-κB signaling pathway, and reducing the proinflammatory cytokines (IL-1β, IL-6, and TNFα), as well as iNOS and COX-2 in the hippocampus of OVX rats. Conclusions: The present study demonstrated that vitamin D and 17β-estradiol could upregulate each other's receptors and regulate the AMPK/NF-κB pathway to relieve the OVX-induced depressive-like state. The results should stimulate translational research towards the vitamin D potential for prevention or treatment of menopause-related depression.