熊脱氧胆酸对小鼠结肠癌抑制作用及机制

目的 探讨熊脱氧胆酸(UDCA)对1,2-二甲肼(DMH)所致小鼠结肠癌抑制作用及可能机制.方法 ICR小鼠喂养1周后,按体重随机分为3组,其中2组腹腔注射DMH,剂量30mg/(kg.bw),每周1次,连续6周诱导结肠癌模型,另一组为空白对照组.从第7周开始在一组(UDCA组)饲料中添加UDCA,剂量3g/kg;另一组(DMH组)饮食不做处理.所有各组均喂食标准AIN-93饲料,28周后处死小鼠,取结肠粘膜进行小鼠碱性鞘磷脂酶(alk-SMase)的活性表达分析.结果 与DMH组相比,给予UDCA组小鼠结肠肿瘤数目明显减少(t=2.77,P<0.05),病理检查肿瘤恶性程度也显著低于DMH组;alk-SMase活性检测中,UDCA组结肠粘膜及内容物alk-SMase活性分别为22.56%和28.97%,其中结肠内容物活性UDCA组比DMH组提高了近14倍;蛋白免疫印迹试验时,UDCA组alk-SMase蛋白表达明显强于DMH组.结论 UDCA对DMH所致小鼠结肠癌有抑制作用,其可能的机制是通过上调小鼠结肠粘膜alk-SMase活性及表达.     

SH2-B β在肥胖小鼠下丘脑和肺内表达及作用

目的探讨高脂饮食诱导肥胖小鼠下丘脑及肺内SH2-Bβ表达与肥胖和炎症之间关系。方法c57BL/6小鼠45只,随机分为对照组和肥胖组,对照组20只,肥胖组25只;高脂饮食制备肥胖模型。利用免疫组织化学法,测定各组小鼠肺内SH2-Bβ表达变化;western blot检测下丘脑SH2-Bβ蛋白变化;应用小鼠肺功能仪检测气道阻力变化。结果肥胖小鼠肺内可见大量炎性细胞浸入,气道上皮及炎性细胞均高表达SH2-Bβ,肥胖组小鼠肺内SH2-Bβ平均光密度值为(0.685±0.025),明显高于对照组的(0.127±0.019)(t=56.19,P<0.01),下丘脑SH2-Bβ免疫阳性产物平均光密度值为(0.686±0.016),明显低于对照组的(2.487±0.014)(t=267.88,P<0.01);肥胖组小鼠气道阻力较对照组明显增高(P<0.01)。结论高脂饮食可使小鼠下丘脑内SH2-Bβ表达下调近而导致肥胖;肺内气道上皮和炎性细胞SH2-Bβ过表达使气道阻力增加。     

Pathways for Memory,Cognition and Emotional Context: Hippocampal,Subgenual Area 25, and Amygdalar Axons Show Unique Interactions in the Primate Thalamic Reuniens Nucleus

The reuniens nucleus (RE) is situated at the most ventral position of the midline thalamus. In rats and mice RE is distinguished by bidirectional connections with the hippocampus and medial prefrontal cortex (mPFC) and a role in memory and cognition. In primates, many foundational questions pertaining to RE remain unresolved. We addressed these issues by investigating the composition of the rhesus monkey RE in both sexes by labeling for GABA, a marker of inhibitory neurons, and for the calcium-binding proteins parvalbumin (PV), calbindin (CB), and calretinin (CR), which label thalamic excitatory neurons that project to cortex. As in rats and mice, the macaque RE was mostly populated by CB and CR neurons, characteristic of matrix-dominant nuclei, and had bidirectional connections with hippocampus and mPFC area 25 (A25). Unlike rodents, we found GABAergic neurons in the monkey RE and a sparser but consistent population of core-associated thalamocortical PV neurons. RE had stronger connections with the basal amygdalar complex than in rats or mice. Amygdalar terminations were enriched with mitochondria and frequently formed successive synapses with the same postsynaptic structures, suggesting an active and robust pathway to RE. Significantly, hippocampal pathways formed multisynaptic complexes that uniquely involved excitatory projection neurons and dendrites of local inhibitory neurons in RE, extending this synaptic principle beyond sensory to high-order thalamic nuclei. Convergent pathways from hippocampus, A25, and amygdala in RE position it to flexibly coordinate activity for memory, cognition, and emotional context, which are disrupted in several psychiatric and neurologic diseases in humans.SIGNIFICANCE STATEMENT The primate RE is a central node for memory and cognition through connections with the hippocampus and mPFC. As in rats or mice, the primate RE is a matrix-dominant thalamic nucleus, suggesting signal traffic to the upper cortical layers. Unlike rats or mice, the primate RE contains inhibitory neurons, synaptic specializations with the hippocampal pathway, and robust connections with the amygdala, suggesting unique adaptations. Convergence of hippocampal, mPFC, and amygdalar pathways in RE may help unravel a circuit basis for binding diverse signals for conscious flexible behaviors and the synthesis of memory with affective significance in primates, whereas disruption of distinct circuit nodes may occur in psychiatric disorders in humans.     

Expression of TLR2 and TLR5 in distal ileum of mice with obstructive jaundice and their role in intestinal mucosal injury

IntroductionThe aim was to investigate the expression of TLR2 and TLR5 in the distal ileum of mice with obstructive jaundice (OJ) and their role in intestinal mucosal injury.Material and methodsA total of 100 male C57BL/6J mice were randomly assigned to two groups: (I) sham operation (SH); (II) bile duct ligation (BDL). The mice were respectively sacrificed before operation and on the 1^st, 3^rd, 5^th and 7^th days after operation to collect specimens. Various indicators were detected by PCR, immunohistochemistry and other methods.ResultsTLR2 was increased gradually with the extension of OJ time in the BDL group (p < 0.05). However, the changes in the expression of TLR5 were not obvious at different time points. The amount of Bifidobacteria and Lactobacillus showed downward trends in intestinal tract of the BDL group. Furthermore, the amount of Escherichia coli was increased in intestinal tract of the BDL group. The pathological score of intestinal mucosa and the expression of NF-κB increased gradually in the BDL group with the extension of OJ time. There were positive correlations between the pathological score of intestinal mucosa and expressions of TLR2(r = 0.767, p < 0.05) and NF-κB (r = 0.817, p < 0.05) in BDL group. NF-κB expression was positively correlated with TLR2 expression(r = 0.706, p < 0.05).ConclusionsDisturbance of intestinal flora caused by OJ could increase the expression of NF-κB via up-regulating the expression of TLR2 to activate the downstream signaling pathway, thus aggravated the injury of intestinal mucosa.     

转录因子FoxO1、FoxO3a在KKAy胰岛素抵抗糖尿病小鼠肌肉和肝组织中的表达

目的研究FoxO1和FoxO3 a在胰岛素抵抗糖尿病动物模型KKAy小鼠肌肉和肝中的表达,了解它们在胰岛素抵抗机制中所起的作用。方法对照组为16周龄C57BL小鼠7只,实验组为KKAy糖尿病小鼠7只;小鼠4周龄开始普通饲料喂养至12周龄,随后高脂饲料喂养4周,连续2次随机血糖≥16.7 mmol/L诊断为糖尿病。取股四头肌和肝加上组织裂解液B radford法测定蛋白浓度,W estern B lot方法检测肌肉和肝组织中FoxO1和FoxO3 a蛋白的表达。结果KKAy糖尿病小鼠FoxO1肝和肌肉中表达显著高于对照组小鼠;FoxO3 a肝表达对照组和糖尿病组之间没有差别,肌肉组织表达在糖尿病组显著高于对照组。结论FoxO1和FoxO3 a在胰岛素抵抗和糖尿病状态下表达显著增加,可能在胰岛素抵抗和糖尿病的发病机制中起重要作用。     

Functional Fiber Reduces Mice Obesity by Regulating Intestinal Microbiota

Obesity may cause metabolic syndrome and has become a global public health problem, and dietary fibers (DF) could alleviate obesity and metabolic syndrome by regulating intestinal microbiota. We developed a functional fiber (FF) with a synthetic mixture of polysaccharides, high viscosity, water-binding capacity, swelling capacity, and fermentability. This study aimed to investigate the effect of FF on obesity and to determine its prevention of obesity by modulating the gut microbiota. Physiological, histological, and biochemical parameters, and gut microbiota composition were investigated in the following six groups: control group (Con), high-fat diet group (HFD), low-fat diet group (LFD, conversion of HFD to LFD), high-fat +8% FF group (8% FF), high-fat +12% FF group (12% FF), and high-fat +12% FF + antibiotic group (12% FF + AB). The results demonstrated that 12% FF could promote a reduction in body weight and epididymal adipocyte area, augment insulin sensitivity, and stimulate heat production from brown adipose tissue (BAT) (p < 0.05). Compared with the HFD, 12% FF could also significantly improve the intestinal morphological integrity, attenuate systemic inflammation, promote intestinal microbiota homeostasis, and stabilize the production of short-chain fatty acids (SCFAs) (p < 0.05). Consistent with the results of 12% FF, the LFD could significantly reduce the body weight and epididymal adipocyte area relative to the HFD (p < 0.05), but the LFD and HFD showed no significant difference (p > 0.05) in the level of inflammation and SCFAs. Meanwhile, 12% FF supplementation showed an increase (p < 0.05) in the abundance of the Bifidobacterium, Lactococcus, and Coprococcus genus in the intestine, which had a negative correlation with obesity and insulin resistance. Additionally, the treatment with antibiotics (12% FF + AB) could inhibit the effect of FF in the HFD. The Kyoto Encyclopedia of Genes and Genomes (KEGG) function prediction revealed that 12% FF could significantly inhibit the cyanogenic amino acid metabolic pathway and decrease the serum succinate concentration relative to the HFD group. The overall results indicate that 12% FF has the potential to reduce obesity through the beneficial regulation of the gut microbiota and metabolites.     

HBV转基因小鼠肝脏NKT细胞功能与PD1、CD28表达分析

目的研究HBV转基因小鼠肝脏中NKT细胞的功能与表面PD1、CD28表达的关系。方法分离小鼠肝脏、脾脏、胸腺和腹膜淋巴结单个核细胞,利用流式细胞检测技术,分别检测其淋巴细胞中NKT细胞的频率,同时检测肝脏NKT细胞PD1、CD28的表达及IFN-γ、IL-4的分泌功能,比较肝脏、脾脏、胸腺和腹膜淋巴结这几个主要免疫组织淋巴细胞中NKT细胞所占的比例,并分析肝脏NKT细胞PD1、CD28的表达与细胞功能的关系。结果与正常同品系小鼠比较,HBV转基因小鼠肝脏、脾脏、胸腺和腹膜淋巴结NKT细胞数量明显减少(P<0.05),与脾脏、胸腺和腹膜淋巴结相比,肝脏淋巴细胞中含有大量的NKT细胞;与正常同品系小鼠比较,HBV转基因小鼠肝脏NKT细胞PD1的表达明显增多(P<0.05),CD28的表达明显减少(P<0.05),肝脏NKT细胞IFN-γ、IL-4的分泌功能明显降低(P<0.05)。结论肝脏中含有大量的NKT细胞,HBV转基因小鼠肝脏NKT细胞的功能存在明显的缺陷,并提示PD1的增加和CD28的降低可能与NKT细胞功能的下调密切相关。     

Rhodiola rosea polysaccharides promote the proliferation of bone marrow haematopoietic progenitor cells and stromal cells in mice with aplastic anaemia

ContextThe effects of Rhodiola rosea L. (Crassulaceae) polysaccharides (RRPs) on haematopoiesis are poorly understood.ObjectiveTo determine the effects of RRPs on haematopoiesis in mice with aplastic anaemia.Materials and methodsAplastic anaemia was induced in Kunming mice by ⁶⁰Coγ (2.0 Gy) irradiation and cyclophosphamide administration (50 mg/kg/day for 3 consecutive days; intraperitoneal injection). The in vivo effects of RRPs (10, 20, and 40 mg/kg; intraperitoneal injection) on haematopoiesis were analyzed using peripheral blood tests, histopathological examination of haematopoietic tissues, culture of haematopoietic progenitors and bone marrow stromal cells (BMSCs), and Western blotting of Fas and Fas ligand (FasL). The in vitro effects of RRPs on bone-marrow haematopoietic progenitors and BMSCs were also evaluated.ResultsCompared to anaemic controls, high-dose RRPs (40 mg/kg) significantly increased red blood cells (8.21 ± 0.57835 versus 6.13 ± 1.34623 × 10¹²/L), white blood cells (5.11 ± 1.6141 versus l.54 ± 1.1539 × 10⁹/L), and BMSCs (10.33 ± 1.5542 versus 5.87 ± 3.1567 × 10¹²/L) in mice with aplastic anaemia (all p < 0.01). High-dose RRPs significantly increased the formation of colony-forming unit-granulocyte macrophage (CFU-GM), burst-forming unit-erythroid (BFU-E), and colony-forming unit-erythroid (CFU-E; p < 0.01). Fas and FasL protein expression in BMSCs decreased after RRPs administration. Especially at the high dose, RRPs (150 μg/mL) significantly promoted in vitro CFUs-E, BFUs-E, and CFUs-GM formation. RRPs (150–300 μg/mL) also promoted BMSC proliferation.Discussion and conclusionsRRPs helped to promote haematopoietic recovery in mice with aplastic anaemia, facilitating haematopoietic tissue recovery. This study indicated some mechanisms of the haematopoietic regulatory effects of RRPs. Our findings provide a laboratory basis for clinical research on RRPs.     

CD34+细胞在哮喘小鼠中的表达及布地奈德干预的实验研究

目的研究CD34 细胞在卵白蛋白(OVA)致敏小鼠、哮喘小鼠中的表达及布地奈德(BUD)吸入对哮喘小鼠CD34 细胞表达的影响。方法将雄性昆明小鼠随机分成致敏组、哮喘组、BUD干预组、正常对照组。用OVA进行致敏和激发,建立哮喘模型。常规检测骨髓、外周血中有核细胞总数,流式细胞仪检测CD34 细胞。结果致敏小鼠骨髓中CD34 细胞比例为(3.99±1.37)%,较正常小鼠[(2.33±1.27)%]明显增加;外周血中CD34 细胞比例为(1.58±0.63)%,与正常小鼠[(1.50±1.04)%]相比,未见明显变化。哮喘小鼠骨髓中CD34 细胞比例为(5.64±1.87)%,与致敏小鼠相比进一步升高;外周血中CD34 细胞比例为(2.91±1.27)%,与正常小鼠相比亦有明显增加;布地奈德吸入后,骨髓、外周血中CD34 细胞表达分别为(3.77±1.81)%和(1.76±1.06)%,均有明显下降。结论小鼠在OVA致敏状态下骨髓中CD34 细胞表达明显增强,OVA激发后哮喘状态下其表达进一步增强,同时,外周血中CD34 细胞比例也明显增高。布地奈德可以抑制哮喘小鼠骨髓、外周血中CD34 细胞的增殖表达。     

Regional distribution of heme oxygenase, HSP70, and glutathione in brain: relevance for endogenous oxidant/antioxidant balance and stress tolerance

It is generally recognized that lipid peroxides play an important role in the pathogenesis of several diseases and that sulfhydryl groups are critically involved in cellular defense against endogenous or exogenous oxidants. Recent evidence indicates that lipid peroxides directly participate in induction of cytoprotective proteins, such as heat shock proteins (Hsps), which play a central role in the cellular mechanisms of stress tolerance. Heme oxygenase (HO) is a stress protein that has been implicated in defense mechanisms against agents that may induce oxidative injury, such as endotoxins, cytokines and heme and its induction represents a common feature in a number of neurodegenerative diseases. In the present report we studied regional distribution of heme oxygenase (HO) activity and protein expression, together with that of Hps70, in brain of C57BL6 mice. Endogenous lipid peroxidation was investigated on the basis of the analysis of ultra weak chemiluminescence, hydro peroxides and lipid soluble fluorescent products, and compared to the regional distribution of thiols, antioxidant enzymes and trace metals. Our results show that levels of HO activity and expression of inducible Hsp70 and the ratio of GSH/GSSG in the different brain regions examined were positively correlated with the content of peroxides. Substantia Nigra was the brain area exhibiting the highest levels of HO-2, constitutive and inducible Hsp70, GSSG, peroxides, iron, and calcium, in contrast with the lowest content in GSH, GSH/GSSG ratio and glutathione reductase activity, compared to the other cerebral regions examined. Among these, cortex showed the lowest levels of HO-2, Hsp70, GSSG and peroxides that were associated with the highest levels of GSH and GSH/GSSG ratio. These data support the hypothesis that the glutathione redox state and basal peroxides can directly participate in the signaling pathways of heat shock protein expression and hence of stress tolerance.