Maternal consumption of ɷ3 attenuates metabolic disruption elicited by saturated fatty acids-enriched diet in offspring rats

Background and aimsHigh-fat diet (HFD) intake during gestation and lactation has been associated with an increased risk of developing cardiometabolic disorders in adult offspring. We investigated whether metabolic alterations resulting from the maternal consumption of HFD are prevented by the addition of omega-3 (?3) in the diet.Methods and resultsWistar rat dams were fed a control (C: 19% of lipids and ?6:?3 = 12), HF (HF: 33% lipids and ?6:?3 = 21), or HF enriched with ?3 (HFω3: 33% lipids and ?6:?3 = 9) diet during gestation and lactation, and their offspring food consumption, murinometric measurements, serum levels of metabolic markers, insulin and pyruvate sensitivity tests were evaluated. The maternal HFD increased body weight at birth, dyslipidemia, and elevated fasting glucose levels in the HF group. The enrichment of ?3 in the maternal HFD led to lower birth weight and improved lipid, glycemic, and transaminase biochemical profile of the HFω3 group until the beginning of adulthood. However, at later adulthood of the offspring, there was no improvement in these biochemical parameters.ConclusionOur findings show the maternal consumption of high-fat ?3-rich diet is able to attenuate or prevent metabolic disruption elicited by HFD in offspring until 90 days old, but not in the long term, as observed at 300 days old of the offspring.     

大补元煎通过上调BDNF/TrkB/CREB信号通路改善APP/PS1双转基因痴呆小鼠海马突触可塑性

目的:观察大补元煎对APP/PS1痴呆小鼠海马突触可塑性及脑源性神经营养因子(BDNF)/酪氨酸蛋白激酶受体B(TrkB)/环磷酸腺苷反应元件结合蛋白(CREB)信号通路的作用,并探讨其改善突触可塑性的可能机制。方法:将APP/PS1小鼠36只分为模型组、多奈哌齐组(6.5×10~(-4)g·kg~(-1)·d~(-1))和大补元煎组(13.2 g·kg~(-1)·d~(-1)),野生鼠12只设为正常组,正常组和模型组给予等体积生理盐水,各组连续灌胃30 d。应用Morris水迷宫检测各组小鼠的学习记忆能力,应用尼氏染色和高尔基染色观察海马区神经元和突触的病理形态变化,应用免疫荧光(IF)观察海马突触后致密蛋白95(PSD95)及突触素(SYN)的蛋白表达水平,采用蛋白免疫印迹法(Western blot)检测海马中BDNF,TrkB,CREB及磷酸化CREB(p-CREB)的蛋白表达水平。结果:与空白组比较,模型组小鼠平台潜伏期和游泳总路程增加(P0.01),穿越平台次数和目标象限停留时间减少(P0.01),小鼠海马CA3区神经元胞内尼氏体减少或消失,小鼠海马CA3区神经元及树突分支数量、树突棘密度减少(P0.01),小鼠海马SYN,PSD95,BDNF,TrkB及p-CREB的蛋白表达水平减少(P0.01)。与模型组比较,多奈哌齐组和大补元煎组小鼠平台潜伏期和游泳总路程减少(P0.05,P0.01),穿越平台次数和目标象限停留时间增加(P0.05,P0.01),小鼠海马CA3区神经元胞内尼氏体数量增多,小鼠海马CA3区神经元及树突分支数量,树突棘密度增加(P0.05,P0.01),小鼠海马SYN,PSD95,BDNF,TrkB及p-CREB的蛋白表达水平增加(P0.05,P0.01)。结论:大补元煎改善APP/PS1双转基因小鼠突触可塑性的机制可能与其上调小鼠海马中BDNF/TrkB/CREB信号通路有关。     

Chronic brain stimulation rewarding experience ameliorates depression-induced cognitive deficits and restores aberrant plasticity in the prefrontal cortex

Background

Major depressive disorder (MDD) is a multifactorial disease which often coexists with cognitive deficits. Depression-induced cognitive deficits are known to be associated with aberrant reward processing, neurochemical and structural alterations. Recent studies have shown that chronic electrical stimulation of brain reward areas induces a robust antidepressant effect. However, the effects of repeated electrical self-stimulation of lateral hypothalamus - medial forebrain bundle (LH-MFB) on depression-induced cognitive deficits and associated neurochemical and structural alterations in the prefrontal cortex (PFC) are unknown.

Acquired semi-squamatization during chemotherapy suggests differentiation as a therapeutic strategy for bladder cancer

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基于突触可塑性探讨电针改善大脑中动脉闭塞大鼠运动障碍的作用机制

目的：基于突触可塑性观察电针曲池、足三里对大脑中动脉闭塞（MCAO）大鼠运动障碍的改善。方法：将60只雄性SD大鼠随机分为假手术组、模型组、穴位组、非穴组，每组15只。采用Zea Longa线拴法制备MCAO大鼠模型，电针曲池、足三里，干预14 d。通过神经功能评分判断大鼠的神经功能缺损情况；CatWalk步态分析比较各组大鼠运动功能，TTC染色观察脑梗死体积，透射电镜观察突触超微结构和数量，免疫荧光检测缺血侧运动皮层突触相关因子突触后致密物-95（PSD-95)、突触蛋白的表达情况。结果：干预14 d后，与模型组比较，穴位组大鼠神经功能评分降低(P<0.05)；步行速度提高、双足支撑时间缩短(P<0.05)；脑梗死体积减少(P<0.05)；突触超微结构改善明显，突触数量增加(P<0.05)，突触相关因子突触蛋白、PSD-95表达上调(P<0.05)。Catwalk步态参数、脑梗死体积与突触超微结构改善有一致性。结论：电针曲池、足三里穴可改善MCAO大鼠运动障碍，其机制可能与上调突触相关因子的表达，改善突触可塑性有关。     

From the Cover: Echolocating bats rely on an innate speed-of-sound reference

Animals must encode fundamental physical relationships in their brains. A heron plunging its head underwater to skewer a fish must correct for light refraction, an archerfish shooting down an insect must “consider” gravity, and an echolocating bat that is attacking prey must account for the speed of sound in order to assess its distance. Do animals learn these relations or are they encoded innately and can they adjust them as adults are all open questions. We addressed this question by shifting the speed of sound and assessing the sensory behavior of a bat species that naturally experiences different speeds of sound. We found that both newborn pups and adults are unable to adjust to this shift, suggesting that the speed of sound is innately encoded in the bat brain. Moreover, our results suggest that bats encode the world in terms of time and do not translate time into distance. Our results shed light on the evolution of innate and flexible sensory perception.

Every organism must reliably sense its environment in order to survive and reproduce (1). Some sensory systems are innate and unalterable (2), allowing for efficient use even by naïve newborn animals (3–5). Others require learning or experience-dependent development—usually during a critical period during ontogeny (6, 7), though sometimes retained through adulthood (8), allowing for adapting sensing to changing environments (9, 10). The ability to accurately estimate distances with sub-centimeter accuracy is a hallmark of bat echolocation (11–13). Bats achieve this accuracy by means of delay-tuned neurons—neurons that are activated by specific call–echo time delays, supposedly encoding target distance (14–19), although it should be noted that some work suggests that the tuning width of delay-tuned neurons might not allow the accuracy that bats exhibit in delay perception (20). Though delay tuning has been shown to be (at least partially) innate at the neural level (21), this has never been tested behaviorally. Namely, when a newborn bat takes off for the first time, does its brain correctly translate time delays into distance?Translating time into distance relies on a reference of the speed of sound (SOS). This physical characteristic of the environment is not as stable as it may seem. The SOS may change considerably due to various environmental factors such as humidity, altitude, and temperature (22). Bats (Chiroptera) are a specious and widely distributed order of highly mobile and long-lived animals. They therefore experience a range of SOSs (with more than 5% variation, see below) between species, among species, and even within the life of a single individual. We therefore speculated that the reference of the SOS may not be innate to allow for the environmentally dependent SOS experienced by each animal.To test this, we examined the acquisition of the SOS reference by exposing neonatal bats to an increased SOS environment from birth (Materials and Methods). We reared two groups of bats from birth to independent flight in two flight chambers: six bats in normal air (henceforth: “air pups”) and five bats in a helium-enriched air environment (Heliox), where the speed of sound was 15% higher (henceforth: “Heliox pups”). Notably, Heliox pups were never active and did not echolocate in non-Heliox environment (Materials and Methods). This 15% shift is higher than the ecological range and was chosen because it is high enough to enable us to document behavioral changes but low enough so as to allow the bats to function (that is, to fly despite the change in air density). In order to feed, the bats had to fly to a target positioned 1.3 m away from their wooden slit roost. Once the bats learned to fly to the target independently (after ca. 9 wk), we first documented their echolocation in the environment where they were brought up, and we then moved them to the other treatment for testing (Materials and Methods). Because bats adjust their echolocation parameters to the distance of the target, before and during flight (23), we used their echolocation to assess the bats’ target range estimates. If the SOS reference is learned based on experience, the bats raised in Heliox should have learned a faster reference, so that when they flew in normal air, they would have perceived the target as farther than it really was. We also ran the same experiments on adult bats to test adult plasticity.     

Sexual dimorphism in Th17/Treg axis in lymph nodes draining inflamed joints in rats with collagen-induced arthritis

Collagen type II-induced arthritis (CIA) in Dark Agouti rats, a model of rheumatoid arthritis (RA), reproduces sexual dimorphism in the incidence and severity of the human disease. Th17 cells are central in the induction/propagation of autoimmune inflammation in CIA and RA. To assess mechanisms underlying this dimorphism in CIA rats, in lymph nodes draining inflamed joints and adjacent tissues (dLNs) from CIA rats of both sexes Th17/CD25+Foxp3+CD4+ T-regulatory cell (Treg) ratio, Th17 cell redifferentiation in functionally distinct subsets and Treg transdifferentiation into IL-17-producing cells (exTregs) were examined. In female rats (developing more severe CIA than their male counterparts) the higher frequency of all Th17 cells (reflecting partly their greater proliferation), followed by the higher frequency of highly pathogenic IFN-γ/GM-CSF-co-producing cells, but lower frequency of less pathogenic/immunoregulatory IL-10-producing cells among them was found. Additionally, compared with male rats, in female rats the lower frequency of Tregs was observed. Moreover, Tregs from female rats exhibited diminished proliferative and suppressive capacity (judging by PD-1 expression) and enhanced conversion into IL-17-producing cells. Given that TGF-β concentration was comparable in collagen-type II-stimulated dLN cell cultures from female and male rats, the shift in Th17/Treg ratio followed by augmented Th17 cell redifferentiation into IFN-γ/GM-CSF-co-producing cells and Treg transdifferentiation into IL-17-producing cells in female rats was associated with increased concentration of IL-6 in female rat dLN cell cultures, and the higher frequency of IL-1β- and IL-23-producing cells among their dLN cells. The lower frequency of IL-10-producing B cells, presumably B regulatory cells (Bregs) could also contribute to the shift in Th17/Treg ratio in female rat compared with male rat dLNs. Consistently, the lower expression of IL-35 (the cytokine promoting Treg expansion directly and indirectly, by favoring Breg expansion and conversion into IL-10/IL-35-producing cells) in female rat dLN cells was detected. Thus, the study identified putative cellular and molecular substrates of the sexual dimorphism in the immunopathogenesis and clinical outcome of CIA and suggested mechanisms to be targeted in females to improve control of Th17 response, and consequently clinical outcome of CIA, and possibly RA.     

Molecular mechanisms and cellular events involved in the neuroprotective actions of estradiol. Analysis of sex differences

Estradiol, either from peripheral or central origin, activates multiple molecular neuroprotective and neuroreparative responses that, being mediated by estrogen receptors or by estrogen receptor independent mechanisms, are initiated at the membrane, the cytoplasm or the cell nucleus of neural cells. Estrogen-dependent signaling regulates a variety of cellular events, such as intracellular Ca²⁺ levels, mitochondrial respiratory capacity, ATP production, mitochondrial membrane potential, autophagy and apoptosis. In turn, these molecular and cellular actions of estradiol are integrated by neurons and non-neuronal cells to generate different tissue protective responses, decreasing blood-brain barrier permeability, oxidative stress, neuroinflammation and excitotoxicity and promoting synaptic plasticity, axonal growth, neurogenesis, remyelination and neuroregeneration. Recent findings indicate that the neuroprotective and neuroreparative actions of estradiol are different in males and females and further research is necessary to fully elucidate the causes for this sex difference.