Sulfur dioxide derivatives attenuates consolidation of contextual fear memory in mice.

Post-traumatic stress disorder (PTSD) is characterized by an enhancement of traumatic memory. Intervention strategies based on the different stages of memory have been shown to be effective in the prevention and control of PTSD. The endogenous gaseous molecule, sulfur dioxide (SO2), has been reported to significantly exert neuromodulatory effects; however, its regulation of learning and memory remains unestablished. This study aimed to investigate the effects of exogenous SO2 derivatives administration on the formation, consolidation, reconsolidation, retention, and expression of contextual fear memory. Behavioral results showed that both intraperitoneal injection (50 mg/kg, ip) and hippocampal infusion (5 µg/side) of SO2 derivatives (a mixture of sodium sulfite and sodium bisulfite, Na2SO3/NaHSO3, 3:1 M/M) significantly impaired consolidation but had no effect on reconsolidation and retention of contextual fear memory. These findings suggest that the attenuating effects of SO2 on the consolidation of fear memory involves, at least partially, the region of the hippocampus. The findings of this study provide direct evidence for the development of new strategies for PTSD prevention and treatment involving the use of gaseous SO2.

Repeated arctigenin treatment produces antidepressant- and anxiolytic-like effects in mice.

Depression is the root of various diseases. It is one of the most debilitating conditions globally. Antidepressant drugs are usually the first-line of depression treatment. Arctigenin (ARC), one of active ingredient of Arctium lappa L, has been found to exert neuroprotective, anti-decrepitude, and anti-inflammatory activities. Thus, the aim of this study was to investigate the potential antidepressant- and anxiolytic-like effects of ARC using acute and chronic mild stress (CMS) mice model. ICR mice model received acute stress or chronic mild stress assessed by open field test (OFT), novelty suppressed feeding (NSF), sucrose preference test (SPT), forced-swimming test (FST), and tail suspension test (TST). After the final test, blood was collected to detect the serum levels of angiogenin (ANG), thrombopoietin (TPO), and vascular endothelial growth factor (VEGF) by enzyme-linked immunosorbent assay (ELISA). The behavioral results showed that repeated ARC (10, 30 mg/kg) administration significantly relieved the antidepressant- and anxiolytic-like effects. And repeated ARC administration at the dose of 10 and 30 mg/kg could significantly block depressive- and anxiety-like behaviors caused by CMS. Finally, ELISA results showed that ARC administration increased the serum levels of angiogenin (ANG), thrombopoietin (TPO), and vascular endothelial growth factor (VEGF). Results showed that chronic ARC administration produces antidepressant- and anxiolytic-like effects, which provides direct evidence for the first time that ARC may be a novel strategy for the treatment of depression and even stress-related disorders. The present data supports further exploration for developing ARC administration as a novel therapeutic strategy for depression and even stress-related disorders.

Methylene blue exerts rapid neuroprotective effects on lipopolysaccharide-induced behavioral deficits in mice.

Depression is a recurrent neuropsychiatric disorder accompanied with other behavioral deficits, including memory impairment. A few studies have shown that methylene blue (MB) could promote cortical neurogenesis and exert neuroprotective effects on various brain diseases, including bipolar disorder. However, the potential antidepressant effects of MB have not been fully investigated. The present study was designed to investigate the effects of MB pretreatment on behavioral deficits and the underlying mechanisms in a lipopolysaccharide (LPS)-induced depression mouse model. Mice were given saline (5 mL/kg) or MB (5, 20 mg/kg) intraperitoneally (i.p.) 30 min prior to lipopolysaccharide (LPS, 800 µg/kg, i.p.) or the following behavioral tests. Thereafter, serum heme oxygenase 1(HO1) were determined by ELISA. The results showed that LPS significantly induced body weight loss and behavioral deficits that included increased floating time in the forced swimming test, increased immobility time in the tail suspension test, decreased sucrose preference in the sucrose preference test, and memory impairment in the novel object recognition (all p < 0.05) when compared with that of LPS-free mice. MB treatment significantly blocked most of these behavioral deficits induced by LPS when compared with that of mice in LPS-exposed groups. Furthermore, MB pretreatment prevented the LPS-induced decrease in serum level of HO1. These findings suggested that MB exerts rapidly neuroprotective effects in an LPS-induced depression mouse model, which may be involved in its regulation on the peripheral HO system.

Serum 25-hydroxyvitamin D and breast cancer risk: a meta-analysis of prospective studies.

There were some case-control studies, nested case-control studies, and cohort studies with controversial results on the association between serum 25-hydroxyvitamin D [25(OH)D] and breast cancer risk. Case-control studies are prone to selection bias, which limit the strength and quality of the evidence. To overcome the shortcoming of the case-control studies, the meta-analysis of prospective studies including nested case-control studies and cohort studies was conducted. PubMed, Embase, and Web of Science databases were searched, and the last retrieval date was March 24, 2013. For the highest versus the lowest level of serum 25(OH)D, the relative risks (RRs) and its 95% confidence intervals (CIs) from each study were used to estimate summary RR and its 95% CI. Subgroup analyses by geographic region, menopausal status, and adjusted status of RR were also performed, respectively. A dose-response association between serum 25(OH)D concentration and breast cancer risk was assessed. Fourteen articles with 9,110 breast cancer cases and 16,244 controls were included in the meta-analysis. Overall, serum 25(OH)D levels were inversely significantly associated with breast cancer risk (RR = 0.845, 95% CI = 0.750-0.951). Inversely statistically significant associations were observed in North American studies, postmenopausal women, and studies with adjusted and unadjusted RR, respectively. No statistically significant associations were observed in European studies and premenopausal women, respectively. Dose-response analysis showed that every 10 ng/mL increment in serum 25(OH)D concentration was associated with a significant 3.2% reduction in breast cancer risk. This meta-analysis provides evidence of a significantly inverse association between serum 25(OH)D concentration and breast cancer risk.