Vitamin D partially reverses the increase in p‐NF‐κB/p65 immunocontent and interleukin‐6 levels, but not in acetylcholinesterase activity in hippocampus of adult female ovariectomized rats

Effects of irisin on ovariectomy-induced depression, anxiety, and bodyweight growth in female mice

Hormone replacement therapy (HRT) for postmenopausal syndrome (PMS) carries high risks of undesirable side effects. This study explores irisin as a potential alternative to HRT and investigates the underlying mechanisms. Ovariectomized (OVX) female mice was used as an animal model. The experimental mice were divided into sham, OVX, OVX + irisin (1, 3 μg/kg), OVX+ estradiol (0.5 mg/kg), and OVX + irisin + compound C (AMPK inhibitor) groups. Results showed that OVX induced depression, anxiety, and bodyweight growth in female mice. These OVX-induced abnormalities were reversed by irisin treatment, while AMPK inhibitor abolished irisin's function, indicating that irisin's therapeutic effects on OVX mice were achieved by activating AMPK. Moreover, irisin could increase pAMPK levels and ameliorate the overexpression of NF-κB and its downstream factors including inflammatory factors (IL-1β, IL-6, and TNF-α) and neurotoxic mediators (COX-2 and iNOS) in the hippocampus, frontal cortex, and serum of the OVX mice. However, irisin did not affect hypothalamus pAMPK level or food intake. These findings indicate that irisin's therapeutic effects on depression and anxiety may be linked to its inhibition of inflammatory factors and neurotoxic mediators in the serum and brain, occurring through the AMPK/NF-κB pathway. Additionally, irisin's effect of reducing bodyweight may be associated with an increase in serum pAMPK level, rather than a direct impact on food intake. Further mechanistic exploration revealed that the beneficial effects of irisin, including both the attenuation of bodyweight gain and the improvement of neurological deficits, are attributed to the activation of αVβ5 receptors.

Serum Vitamin D Level Correlates Significantly With Leptin and Tumor Necrosis Factor-Alpha in Overweight Postmenopausal Women With Hypertension

Background

Association of serum vitamin D (vitD) with leptin (Lep) and tumor necrosis factor-alpha (TNF-α) is not precisely known in overweight hypertensive (OW-HT) postmenopausal (PMP) women. Hence, the present study was carried out to investigate the body mass index (BMI)-based correlation of serum vitD with Lep and TNF-α in OW-HT PMP women.

Methods

Women subjects in their early PMP (n = 346, age: 51 - 60 years) categorized into three groups had main inclusion criteria of specified range of age, BMI and blood pressure (BP). Enzyme-linked immunosorbent assay (ELISA) and other kit methods were employed to investigate the role of various variables in three subject groups (normal weight normotensive (NW-NT, n = 116, BMI (kg/m2): 22 - 24.9), normal weight hypertensive (NW-HT, n = 115, BMI: 22 - 24.9) and OW-HT (n = 115, BMI: 25 - 29.9) PMP women).

Results

A significant negative linear correlation of vitD with serum Lep and TNF-α, and a significant positive linear correlation of BMI with Lep and TNF-α in OW-HT PMP women were obtained. Significantly higher levels of serum Lep, TNF-α and interleukin-6 (IL-6) were found in OW-HT PMP women, as compared to NW-HT PMP women.

Conclusions

The present study suggests that decreased serum vitD levels correlate with the Lep and TNF-α in OW-HT PMP women. However, further studies may help understand the impact of vitD in cardiovascular events and the influencing factors in OW-HT PMP women.

Profiling inflammatory mechanisms, hyperphosphorylated tau of hippocampal tissue and spatial memory following vitamin D3 treatment in the mice model of vascular dementia

BACKGROUND

The aim of this study was to investigate the effect of vitamin D3 (VitD3) on inflammatory mechanisms, hyperphosphorylated tau (p-tau) in the hippocampus, and cognitive impairment of the mouse model of vascular dementia (VaD).

METHODS

In this study, 32 male mice were randomly assigned to the control, VaD, VitD3 (300 IU/Kg/day), and VitD3 (500 IU/Kg/day) groups. VaD and VitD3 groups were gavaged daily for 4 weeks with a gastric needle. For biochemical assessments, blood samples and the hippocampus were isolated. IL-1β and TNF-α were analyzed by ELISA, and p-tau and other inflammatory molecules were measured by western blot.

RESULTS

VitD3 supplements significantly (P < 0.05) decreased the level of inflammatory factors in the hippocampus and prevented apoptosis. However, regarding p-tau in hippocampal tissue, this decrease was not statistically significant (P > 0.05). The results of behavioral assessments showed that VitD3 significantly improved the spatial memory of treated mice.

CONCLUSION

These results suggest that the neuroprotective effects of VitD3 are mainly associated with their anti-inflammatory effects.

Neuroprotective effects of vitamin D and 17ß-estradiol against ovariectomy-induced neuroinflammation and depressive-like state: Role of the AMPK/NF-κB pathway

Estrogen replacement therapy (ERT) has been proven to relieve menopausal-related mental disorders including depression in postmenopausal women. However, the unsafety of ERT hinders its clinical use. In this study, we would evaluate whether vitamin D (VD), a hormone with optimal safety profile, could relieve the depressive-like symptom in ovariectomized (OVX) rats. Furthermore, we would determine whether vitamin D and 17β-estradiol (E2) exert neurological function through their immunomodulatory effect in OVX rats. Middle-aged female SD rats were randomly divided into four groups, namely, control (SHAM), OVX, OVX + VD, and OVX + E2. Vitamin D (calcitriol, 100 ng/kg) and 17β-estradiol (30 μg/kg) had been daily gavaged in the OVX + VD and OVX + E2 group, respectively. After 10-week administration, vitamin D and 17β-estradiol both showed anti-depressive-like activity in the OVX rats. Using the method of immunofluorescent staining and western blot, vitamin D and 17β-estradiol were demonstrated to upregulate each other's receptors, including VDR, ERα, and ERβ in the hippocampus of OVX rats. Additionally, the upregulation of VDR, calbindin-D28k, and calbindin-D9k suggested that the vitamin D signaling system was amplified by vitamin D and 17β-estradiol. 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. Collectively, 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 could stimulate translational research towards the vitamin D potential for prevention or treatment of menopause-related depression.

Intrastriatal Quinolinic Acid Administration Impairs Redox Homeostasis and Induces Inflammatory Changes: Prevention by Kynurenic Acid

Kynurenic acid (KYNA) and quinolinic acid (QUIN) are metabolites formed in the degradation of tryptophan (Trp). QUIN is a selective NMDA receptor antagonist and may exert neurotoxic effects, whereas KYNA is an agonist of glutamatergic and cholinergic receptors and presents antioxidant properties. KYNA/QUIN ratio is decreased in several central nervous system disorders, but the mechanisms involved are not well elucidated. In the present study, we try to determine the neuroprotective capacity of KYNA on the QUIN effects in redox homeostasis changes (H₂DCF oxidation, superoxide dismutase/catalase (SOD/CAT) ratio, glutathione peroxidase (GPx) activity, sulfhydryl content, and nitrite levels), as well as on inflammatory parameters (levels of TNF-α, IL-1β, and IL-6). KYNA and QUIN effects on the activities of Na⁺,K⁺-ATPase and acetylcholinesterase (AChE) were also evaluated. Thirty-day-old male Wistar rats underwent stereotactic surgery and received intrastriatal injections as follows: group 1-control (PBS-injected), group 2-KYNA (100 μM), group 3-QUIN (150 nM), and group 4-KYNA + QUIN (KYNA-injected followed QUIN-injected). Results demonstrated that the KYNA administration was able to prevent the increase in reactive oxygen species, SOD/CAT ratio, and pro-inflammatory cytokines (IL-1β and IL-6) and the decrease in GPx activity, sulfhydryl content, and nitrite levels caused by QUIN. KYNA was also able to partially prevent the decrease in Na⁺,K⁺-ATPase activity and the increase in AChE activity caused by QUIN. This study may help in the elucidation of neuroprotective effects of KYNA against oxidative and inflammatory insults caused by QUIN in the striatum of young male Wistar rats.

Changes in Inflammatory Response, Redox Status and Na+, K+-ATPase Activity in Primary Astrocyte Cultures from Female Wistar Rats Subject to Ovariectomy

Astrocytes are dynamic glial cells that maintain brain homeostasis, particularly metabolic functions, inflammatory response, and antioxidant defense. Since menopause may be associated with brain dysfunction, in the present study, we evaluated anti- and proinflammatory cytokine release in cortical and hippocampal astrocyte cultures obtained from adult female Wistar rats subjected to ovariectomy, a known experimental model of menopause. We also tested some parameters of metabolic functionality (Na⁺, K⁺-ATPase activity) and cellular redox status, such as antioxidant enzyme defenses (superoxide dismutase and catalase) and the intracellular production of reactive oxygen species in this experimental model. Female adult Wistar rats (180 days-age) were assigned to one of the following groups: sham (submitted to surgery without removal of the ovaries) and ovariectomy (submitted to surgery to removal of the ovaries). Thirty days after ovariectomy or sham surgery, we prepared astrocyte cultures from control and ovariectomy surgery animals. Ovariectomized rats presented an increase in pro-inflammatory cytokines (tumor necrosis factor α, interleukins 1β, 6, and 18) and a decrease in interleukin 10 release, an anti-inflammatory cytokine, in cortical and hippocampal astrocytes, when compared to those obtained from sham group (control). In addition, Na⁺,K⁺-ATPase activity decreased in hippocampal astrocytes, but not in cortical astrocyte cultures. In contrast, antioxidant enzymes did not alter in cortical astrocyte cultures, but increased in hippocampal astrocytes. In summary, our findings suggest that ovariectomy is able to induce an inflammatory response in vivo, which could be detected in in vitro astrocytes after approximately 4 weeks.