Agomelatine, venlafaxine, and running exercise effectively prevent anxiety- and depression-like behaviors and memory impairment in restraint stressed rats.

Several severe stressful situations, e.g., natural disaster, infectious disease out break, and mass casualty, are known to cause anxiety, depression and cognitive impairment, and preventive intervention for these stress complications is worth exploring. We have previously reported that the serotonin-norepinephrine-dopamine reuptake inhibitor, venlafaxine, as well as voluntary wheel running are effective in the treatment of anxiety- and depression-like behaviors in stressed rats. But whether they are able to prevent deleterious consequences of restraint stress in rats, such as anxiety/depression-like behaviors and memory impairment that occur afterward, was not known. Herein, male Wistar rats were pre-treated for 4 weeks with anti-anxiety/anti-depressive drugs, agomelatine and venlafaxine, or voluntary wheel running, followed by 4 weeks of restraint-induced stress. During the stress period, rats received neither drug nor exercise intervention. Our results showed that restraint stress induced mixed anxiety- and depression-like behaviors, and memory impairment as determined by elevated plus-maze, elevated T-maze, open field test (OFT), forced swimming test (FST), and Morris water maze (MWM). Both pharmacological pre-treatments and running successfully prevented the anxiety-like behavior, especially learned fear, in stressed rats. MWM test suggested that agomelatine, venlafaxine, and running could prevent stress-induced memory impairment, but only pharmacological treatments led to better novel object recognition behavior and positive outcome in FST. Moreover, western blot analysis demonstrated that venlafaxine and running exercise upregulated brain-derived neurotrophic factor (BDNF) expression in the hippocampus. In conclusion, agomelatine, venlafaxine as well as voluntary wheel running had beneficial effects, i.e., preventing the restraint stress-induced anxiety/depression-like behaviors and memory impairment

Differential effects of Fe2+ and Fe3+ on osteoblasts and the effects of 1,25(OH)2D3, deferiprone and extracellular calcium on osteoblast viability under iron-overloaded conditions.

One of the potential contributing factors for iron overload-induced osteoporosis is the iron toxicity on bone forming cells, osteoblasts. In this study, the comparative effects of Fe3+ and Fe2+ on osteoblast differentiation and mineralization were studied in UMR-106 osteoblast cells by using ferric ammonium citrate and ferrous ammonium sulfate as Fe3+ and Fe2+ donors, respectively. Effects of 1,25 dihydroxyvitamin D3 [1,25(OH)2D3] and iron chelator deferiprone on iron uptake ability of osteoblasts were examined, and the potential protective ability of 1,25(OH)2D3, deferiprone and extracellular calcium treatment in osteoblast cell survival under iron overload was also elucidated. The differential effects of Fe3+ and Fe2+ on reactive oxygen species (ROS) production in osteoblasts were also compared. Our results showed that both iron species suppressed alkaline phosphatase gene expression and mineralization with the stronger effects from Fe3+ than Fe2+. 1,25(OH)2D3 significantly increased the intracellular iron but minimally affected osteoblast cell survival under iron overload. Deferiprone markedly decreased intracellular iron in osteoblasts, but it could not recover iron-induced osteoblast cell death. Interestingly, extracellular calcium was able to rescue osteoblasts from iron-induced osteoblast cell death. Additionally, both iron species could induce ROS production and G0/G1 cell cycle arrest in osteoblasts with the stronger effects from Fe3+. In conclusions, Fe3+ and Fe2+ differentially compromised the osteoblast functions and viability, which can be alleviated by an increase in extracellular ionized calcium, but not 1,25(OH)2D3 or iron chelator deferiprone. This study has provided the invaluable information for therapeutic design targeting specific iron specie(s) in iron overload-induced osteoporosis. Moreover, an increase in extracellular calcium could be beneficial for this group of patients

Extracellular Fe2+ and Fe3+ modulate osteocytic viability, expression of SOST, RANKL and FGF23, and fluid flow-induced YAP1 nuclear translocation

Abstract Iron overload negatively affects bone mass and strength. However, the impact of iron excess on osteocytes—important bone cells for mechanotransduction and remodeling—is poorly understood. Herein, we examined the effects of iron exposure on osteocytes during their maturation process. We discovered that iron overload caused apoptosis of osteocytes in early and late stages of differentiation. Notably, the expression of key proteins for iron entry was downregulated during differentiation, suggesting that mature osteocytes were less susceptible to iron toxicity due to limited iron uptake. Furthermore, iron overload also enriched a subpopulation of mature osteocytes, as indicated by increased expression of Dmp1, a gene encoding protein for bone mineralization. These iron-exposed osteocytes expressed high levels of Sost, Tnfsf11 and Fgf23 transcripts. Consistently, we demonstrated that exogenous FGF23 stimulated the formation and survival of osteoclasts, suggesting its regulatory role in bone resorption. In addition, iron overload downregulated the expression of Cx43, a gene encoding gap junction protein in the dendritic processes, and impaired YAP1 nuclear translocation in response to fluid flow in differentiated osteocytes. It can be concluded that iron overload induces cellular adaptation in differentiating osteocytes, resulting in insensitivity to mechanical stimulation and potential disruption of the balance in bone remodeling

Expression of brain-derived neurotrophic factor (BDNF) in stressed rats pre-treated with drugs and exercise.

<p>Hippocampal BDNF protein expression normalized by β-actin in 4-week stressed rats subjected to agomelatine (Ago) or venlafaxine (Vlx) treatment or voluntary wheel running (Ex) as determined by Western blot analysis. <i>Inset</i>: representative electrophoresis bands of BDNF and β-actin. Numbers of animals are noted in parentheses. ^†<i>p</i> < 0.05, ^†††<i>p</i> < 0.001 compared with vehicle (Veh)-treated group.</p

Time-dependent changes in the stress-induced anxiety-like behaviors in rats as determined by EPM and ETM.

<p>(A) Percent open arm entry, (B) percent open arm time, (C) percent closed arm entry, (D) percent closed arm time, and (E) total number of entries in 1-, 4-, and 8-week stressed male rats, as determined by elevated plus-maze (EPM). (F) One-way escape latency, (G) baseline time, (H) avoidance 1, and (I) avoidance 2 in stressed rats, as determined by elevated T-maze (ETM). Numbers of animals are noted in parentheses. *<i>p</i> < 0.05, **<i>p</i> < 0.01, ***<i>p</i> < 0.001 stress vs. control.</p

Effects of pharmacological treatments and voluntary wheel running on anxiety-like behaviors in stressed rats.

<p>(A) Percent open arm entry, (B) percent open arm time, (C) percent closed arm entry, (D) percent closed arm time, and (E) total arm entries in stressed rats subjected to agomelatine (Ago) or venlafaxine (Vlx) treatment or voluntary wheel running (Ex), as determined by elevated plus-maze (EPM). (F) One-way escape latency, (G) baseline, (H) avoidance 1, and (I) avoidance 2 in stressed rats as determined by elevated T-maze (ETM). Numbers of animals are noted in parentheses. ^†<i>p</i> < 0.05, ^†††<i>p</i> < 0.001 compared with vehicle (Veh)-treated group.</p