1,3-dichloro-2-propanol induced lipid accumulation in HepG2 cells through cAMP/protein kinase A and AMP-activated protein kinase pathways via Gi/o-coupled receptors

1,3-dichloro-2-propanol (1,3-DCP) is a food born hepatoxic chloropropanol contaminant that has been detected in a wide range of foods. In the present study, we investigated the effects and mechanisms of 1,3-DCP on lipid accumulation in HepG2 cells. The data showed 1,3-DCP significantly increased intracellular content of triglyceride (TG) and total cholesterol (TC) at 0.5–2 μg/mL. Further results showed that 1,3-DCP greatly decreased cyclic AMP (cAMP) level. In addition, 1,3-DCP inhibited PKA and AMPK signaling pathway, but had no influence on intracellular calcium and regulated proteins. Moreover, Gi/o protein inhibitor PTX significantly inhibited 1,3-DCP induced decrease of cAMP, p-PKA and p-AMPK expression. Furthermore, 1,3-DCP significantly decreased GPR41 and GPR43 expression, but had no effect on GPR109B.Thus, we concluded that 1,3-DCP induced lipid accumulation in HepG2 cells through cAMP/PKA and AMPK signaling pathways via Gi/o-coupled receptor.     

Ginsenoside Rg3 attenuates ovariectomy-induced osteoporosis via AMPK/mTOR signaling pathway

Ginsenoside Rg3, a ginsenoside isolated from Panax ginseng, can regulate autophagy via AMP-activated protein kinase/mammalian target of rapamycin (AMPK/mTOR) signaling pathway. AMPK/mTOR signaling and autophagy have been reported to be involved in osteogenesis. Here, the effect of Rg3 on ovariectomy (OVX)-induced osteoporosis is explored. In vivo, rats were treated with 20 mg/kg Rg3 after OVX and the body weight (BW) was monitored. Bone mineral density (BMD), hematoxylin–eosin staining of femur tissues, osteogenesis, autophagy, and AMPK/mTOR signaling were analyzed. In vitro, MC3T3-E1 cells were treated with 0, 1, 5, 10, 20, and 100 μmol/L Rg3. 10 and 20 μmol/L Rg3, which had no significant effect on cell viability and significantly affected AMPK/mTOR signaling, were chosen for further analysis. Then osteogenic differentiation was induced with Rg3 or/and AMPK inhibitor (Compound C). AMPK/mTOR signaling, autophagy, osteogenic differentiation, and mineralization by Alizarin Red staining were analyzed. The expression or activity of AMPK/mTOR signaling-related proteins, autophagy markers, and osteogenesis markers was measured by western blotting or commercial kits, and cell viability by cell counting kit-8 assay kits. Rg3 significantly alleviated OVX-induced BW increases, BMD declines and histological changes of femur tissues, promoted osteogenesis, autophagy, and AMPK signaling, but inhibited mTOR signaling in vivo. Moreover, Rg3 significantly enhanced AMPK signaling, autophagy, osteogenic differentiation, and mineralization, but suppressed mTOR signaling in vitro. However, Compound C significantly reversed Rg3-induced alterations in vitro, indicating that Rg3 regulated autophagy, osteogenic differentiation, and mineralization via AMPK/mTOR signaling. Hence, it was speculated that Rg3 might attenuate OVX-induced osteoporosis via AMPK/mTOR signaling pathway.     

AMPK/mTOR信号通路在肿瘤中的研究现状

肿瘤是信号传递过程中发生紊乱,导致细胞无限增生而形成的恶性结果.针对异常传递通路的深入研究,以发现可用的高效作用靶点是目前关于肿瘤治疗的研究热点.单磷酸腺苷活化蛋白激酶(AMPK)/雷帕霉素靶蛋白(mTOR)信号通路在细胞和个体水平维持能量及氧化还原平衡方面起着举足轻重的作用,信号传递异常可能打破这种平衡而引发肿瘤.该文将对AMPK/mTOR信号通路及其激动剂在肿瘤中的研究现状进行综述.     

益肾排毒丸调节AMPK/ACC信号通路对db/db小鼠肝损伤的保护作用研究

目的：探究益肾排毒丸（YSPDW）对db/db小鼠肝损伤的保护作用及其对脂代谢通路的影响机制。方法：C57BL/6小鼠作为空白对照组、8周龄的db/db小鼠分为非酒精性脂肪肝（non-alcoholic fatty liver disease,NAFLD）模型组、益肾排毒丸治疗组和二甲双胍阳性对照组。给药8周后检测小鼠肝脏系数、随机血糖、肝功能（丙氨转氨酶ALT、谷草转氨酶AST）、血脂（总胆固醇TC、三酰甘油TG、高密度脂蛋白胆固醇HDL-C、低密度脂蛋白胆固醇LDL-C）、肝脏脂质（TC、TG）、肝脏抗氧化因子（谷胱甘肽过氧化物酶GSH-Px、谷胱甘肽GSH、超氧化物歧化酶SOD、丙二醛MDA、过氧化氢酶CAT）、肝脏炎性因子（TNF-α、IL-6、IL-1β、MCP-1）等指标的变化。HE和PAS染色评估小鼠肝脏形态变化、脂肪变性和糖原沉积。Western blot检测脂代谢AMPK/ACC信号通路相关蛋白表达。结果：与模型组相比,益肾排毒丸给药组和二甲双胍组小鼠随机血糖和肝脏系数显著降低。生化指标检测结果显示益肾排毒丸可显著降低NAFLD模型小鼠血清AST、ALT、TC、TG水平和肝组织TC、TG、MDA水平,升高HDL-C含量,发挥肝保护作用;ELISA结果表明益肾排毒丸能明显升高NAFLD小鼠肝组织GSH-Px、GSH和SOD活性,显著降低肝脏炎性细胞因子TNF-α、IL-6、IL-1β和MCP-1的水平,表明益肾排毒丸可增加机体抗氧化能力,抑制炎症因子释放。HE和PAS结果显示益肾排毒丸可明显减轻肝组织脂肪变性和炎症细胞浸润,改善肝细胞的结构和形态完整。Western blot结果表明,益肾排毒丸能激活AMPK/ACC信号通路,显著增加模型小鼠肝脏p-AMPK和p-ACC蛋白表达。结论：益肾排毒丸可能通过促进AMPK/ACC信号通路来改善肝脏氧化应激、炎性反应,减少脂质合成,从而改善NAFLD的肝损伤。     

Nicotine-produced relearning deficit in C57BL/6J and DBA/2J mice

Acute nicotine administration has been shown to influence the acquisition and retention of learning tasks. In order to investigate the many possible behavioral and pharmacological effects of nicotine, a modified 2×2 statedependent learning design was used to assess nicotine's effects on active avoidance learning. Male and female mice of the C57BL/6J (C57) and DBA/2J (DBA) inbred strains were injected with a control solution or with 0.5, 1.0, or 2.0 mg/kg nicotine 5 min before the start of training and, following a 24-h period, 5 min before retraining. Nicotine had no effect on the acquisition of the learning task but, depending on strain and sex, did have an effect on relearning. Relearning in the C57 males was unaffected by nicotine injection, whereas the most prominent effect of nicotine in the C57 females and the DBA males and females was a retrieval deficit. The prevalence of a nicotine-induced retrieval deficit in the present experiment suggests that those mechanisms underlying the retrieval of previously learned information are, in part, mediated or modulated by perturbations within nicotine-sensitive areas of the central nervous system.     

槲皮素对胃癌相关p53/AMPK/mTOR信号通路的影响

目的　探讨槲皮素（QE）对胃癌相关p53/AMPK/mTOR信号通路的影响。方法　将胃癌细胞分为QE组和溶剂组,QE组以DMSO为溶剂按配制QE浓度分别为0.02、0.04、0.06及0.08 mmol/L,对细胞进行干预,分别为QEA、QEB、QEC、QED组,溶剂组加入等量不含QE的溶剂。MTT实验检测槲皮素对胃癌细胞增殖的影响;MDC染色法检测槲皮素对胃癌细胞自噬的影响;双染法检测槲皮素对胃癌细胞凋亡的影响;实时荧光定量聚合酶链反应检测细胞内p53、AMPK及mTOR的mRNA相对表达水平;Western blot检测细胞内LC3Ⅱ/LC3Ⅰ、P53、AMPK、mTOR蛋白表达差异。结果　与溶剂组相比,QE各剂量组胃癌细胞的自噬程度和凋亡率均显著增加,细胞中LC3Ⅱ/Ⅰ蛋白表达量上调,p53、AMPK mRNA和蛋白水平均上调,mTOR的mRNA和蛋白表达量均下调（P＜0.05）,且呈剂量依赖性。结论　QE可以抑制胃癌细胞增殖,诱导其发生自噬、促进其凋亡,其作用机制可能与p53/AMPK/mTOR信号通路有关。     

Differential responsiveness to cocaine in C57BL/6J and DBA/2J mice

 The present study compared cocaine-induced hyperlocomotion and cocaine IV self-administration in DBA/2J and C57BL/6J mice. In the locomotor activity experiment, these strains were tested for hyperlocomotion after IP cocaine injection (0–60.0 mg/kg), using a Digiscan Animal Activity Monitoring System. In the cocaine IV self-administration experiment, they were compared for their ability to acquire and maintain cocaine self-administration in operant chambers with levers as the manipulanda. Animals were first trained to respond for food as a reinforcer (condensed milk solution); they were then submitted to surgical IV insertion of an indwelling catheter, and required to respond for IV cocaine (0.25–4.0 mg/kg per injection) as a reinforcer. DBA/2J mice showed significantly higher maximal cocaine-induced hyperlocomotion, more rapid acquisition of cocaine self-administration, and significantly lower rates of cocaine self-administration. Cocaine concentration in the brains of DBA/2J and C57BL/6J mice failed to differ following IP injection, suggesting that distribution factors were not involved in the differential responses to cocaine. Although not conclusive, this pattern of effects may suggest that cocaine has greater reinforcing efficacy in DBA/2J mice, confirming genetic make-up as a determinant factor in cocaine taking behavior. Received: 6 October 1997 / Final version: 4 January 1998     

Alginate oligosaccharide alleviates senile osteoporosis via the RANKL–RANK pathway in D-galactose-induced C57BL/6J mice

Osteoporosis is a systemic skeletal disorder characterized by reduced bone mineral density (BMD) and bone quality and increased bone porosity, which increase the risk of bone fracture. Inflammation, one of the important mechanisms related to aging, is associated with osteoporosis. Treatment with anti-inflammatory agents is effective for alleviating senile osteoporosis. Alginate oligosaccharide (AOS) can prevent and treat diseases related to inflammation, oxidative stress, and immunity. This study evaluates the effect of AOS on osteoporosis and investigates the underlying mechanism. Osteoporosis model was induced by D-galactose (D-gal) (200 mg kg^?1 day^?1) for eight weeks. Three groups were administered via AOS (50, 100, and 150 mg kg^?1 day^?1) for four weeks, while a control group received sterile water (5 ml kg^?1 day^?1) for 8 weeks. The results showed that AOS improved bone density and bone microstructure in D-gal-induced osteoporosis mice. AOS inhibited osteoclast proliferation, probably through the suppression of receptor activator of nuclear factor-kappa B ligand (RANKL)-associated nuclear factor kappa B (NF-κB) and c-Fos signaling pathway. AOS also increased osteoprotegerin (OPG) expression and competitively inhibited the binding between RANK and RANKL in senile osteoporosis. Further, AOS decreased the secretion of serum osteocalcin and reduced bone conversion. Together, these results demonstrate the anti-osteoporosis activity of AOS in mice with osteoporosis.     

Comparison of 2,3,7,8-tetrachlorodibenzo-p-dioxin-mediated hepatotoxicity in C57BL/6J and DBA/2J mice

The toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) was examined by clinical chemistry and liver histopathology in Ah-responsive C57BL/6J (C57) and Ah-nonresponsive DBA/2J (DBA) mice. Hepatotoxicity was assessed at 1, 3, and 7 d following a single ip injection of TCDD at doses that maximally induce hepatic aryl hydrocarbon hydroxylase (AHH) activity (3 micrograms/kg for C57 and 30 micrograms/kg for DBA mice) and at doses approaching the LD50 (150 micrograms/kg for C57 and 600 micrograms/kg for DBA mice). Histological examination of liver sections was found to be a more sensitive detection method for TCDD-induced hepatic changes than clinical chemistry analyses. Dramatic differences in the development and type of liver injury were observed between TCDD-treated C57 and DBA mice. C57 mice given 3 micrograms TCDD/kg developed mild to moderate hepatic lipid accumulation in the absence of both inflammation and necrosis. Severe fatty change and mild inflammation and necrosis occurred in C57 mice that received 150 micrograms TCDD/kg. In contrast, DBA mice exposed to 30 micrograms TCDD/kg developed hepatocellular necrosis and inflammation without any fatty change. Only slight hepatic lipid accumulation occurred with some necrosis and inflammation in DBA mice given 600 micrograms TCDD/kg. The Ah locus may play a role in determining the sensitivity of C57 mice to the steatotic effects of TCDD.     

Ethanol preexposure increases ethanol self-administration in C57BL/6J and DBA/2J mice

Genetic variables are thought to interact with environmental factors, such as alcohol exposure history, to produce individual differences in alcohol abuse and alcoholism. The objective of this study was to test the potential interaction between genetic predisposition to consume alcohol and alcohol pretreatment on subsequent self-administration. To accomplish this goal, four groups of mice from the ethanol-avoiding DBA/2J (D2) and ethanol-preferring C57BL/6J (B6) inbred strains were exposed to saline, acute ethanol (2 g/kg), or chronic intermittent ethanol (1 or 2 g/kg) intraperitoneal (i.p.) injections. Locomotor activity was monitored after each injection. After preexposure, animals were given a two-bottle choice test with various concentrations of ethanol/sucrose vs. sucrose or ethanol vs. water for 4 days at each concentration. Then, all animals were challenged with a 2.0 g/kg ethanol i.p. injection and locomotor activity was assessed. Acute and chronic ethanol pretreatment increased locomotor activity in response to a challenge dose of ethanol (2 g/kg) in D2 mice but had no effect on B6 mice. Prior exposure to ethanol altered the amount of ethanol consumed in a mouse strain-dependent manner. D2 mice showed a positive relationship between ethanol intake and dose or duration of ethanol preexposure. B6 mice preexposed to ethanol consumed more ethanol than naive animals, independent of dose or duration of exposure. During the last phase of self-administration testing, D2 mice exposed to chronic ethanol (2 g/kg) consumed as much ethanol as B6 from the same pretreatment condition. After a history of ethanol self-administration, saline control mice from the D2 strain showed equal locomotor activation as compared to D2 mice that were pretreated with ethanol injections. B6 mice showed no change in locomotor activity after ethanol self-administration or injection. These results demonstrate that genetic predisposition to avoid alcohol (D2 mice) can be modified by a history of preexposure and that a predisposition to prefer alcohol (B6 mice) may be also amenable to influence by drug history. In general, the results of this study suggest that genetic factors may interact with previous exposure to ethanol to modify ethanol self-administration.     

Effect of mercury on aryl hydrocarbon receptor-regulated genes in the extrahepatic tissues of C57BL/6 mice

The individual toxic effects of aryl hydrocarbon receptors (AhR) ligands such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) or heavy metals typified by mercury (Hg²⁺) has been previously demonstrated. However, little is known about the combined toxic effects of TCDD and Hg²⁺in vivo. Therefore, we examined the effect of exposure to Hg²⁺ (2.5 mg/kg) in the absence and presence of TCDD (15 μg/kg) on the AhR-regulated genes using C57Bl/6 mice. Hg²⁺ alone did not affect kidney, lung, or heart Cyp1a1/1a2/1b1 mRNA levels. On the contrary, Hg²⁺ alone significantly induced kidney Cyp1a1/1a2/1b1 and lung Cyp1b1 protein and catalytic activities. Hg²⁺ also induced Nqo1, Gsta1, and HO-1 at the mRNA, protein, and activity levels in the kidney and heart but not in the lung. Upon co-exposure to Hg²⁺ and TCDD, Hg²⁺ significantly potentiated the TCDD-mediated induction of kidney and lung Cyp1a1/1a2/1b1 mRNA levels, while it decreased their kidney protein and catalytic activity and it increased their lung protein. In addition, Hg²⁺ potentiated the TCDD-mediated induction of Nqo1, Gsta1, and HO-1 at mRNA, protein and activity levels in all tissues. The present study demonstrates that Hg²⁺ modulates the constitutive and TCDD-induced AhR-regulated genes in a time-, tissue- and, AhR-regulated enzyme genes manner.     

Diet-induced obesity and cardiovascular regulation in C57BL/6J mice

1. In the present study, we determined the effect of diet-induced obesity on cardiovascular and metabolic regulation in mice at standard laboratory temperatures (ambient temperature (Ta) = 22 degrees C) and during exposure to thermoneutrality (Ta = 30 degrees C). 2. Male C57BL/6J (B6) mice fed a high-fat diet (HFF; n = 17) or chow (CHW; n = 14) for 15 weeks were surgically instrumented with telemetry devices, housed in metabolic chambers and assigned to either control or atenolol treatment (25 mg/kg per day in drinking water) to determine the effects of obesity on baseline cardiovascular function and on the responses to thermoneutrality and 24 h fasting. Mean arterial pressure (MAP), heart rate (HR), arterial pressure and HR variability (time and frequency domain), oxygen consumption (VO2) and locomotor activity were determined. 3. The HFF mice exhibited increased bodyweight (+10.6 +/- 4.1 g), moderate light period hypertension (+8.6 +/- 2.6 mmHg), no difference in HR and increased HR variability at standard laboratory temperature compared with CHW controls. Atenolol produced less of a decrease in HR in HFF mice (-42 +/- 10 b.p.m.) compared with CHW controls (-73 +/- 15 b.p.m.). Acute exposure to thermoneutrality (Ta = 30 degrees C) reduced HR similarly in both HFF and CHW mice (approximately 175 b.p.m.), but reduced MAP less in HFF than in CHW mice (-7.3 +/- 2.5 and -15.2 +/- 1.0 mmHg), respectively. Atenolol treatment had only minor effects on the HR response to thermonuetrality (-114 +/- 13 and -129 +/- 8 b.p.m. in HFF and CHW mice, respectively). The HFF mice displayed greater fasting-induced reductions in light period MAP than did CHW mice (-10.0 +/- 1.1 vs-3.1 +/- 3.5 mmHg, respectively), whereas HR was decreased equally in both groups. Fasting-induced increases in HR variability were attenuated in HFF mice. 4. We conclude that diet-induced obesity produced generally minor changes in cardiovascular regulation in B6 mice at baseline, some of which are distinct from the effects of diet-induced obesity in larger animal models. In contrast, acute variations in Ta or caloric availability produce pronounced alterations in cardiovascular function in either lean or obese mice, which are generally evident after atenolol and, thus, presumably not due exclusively to variation in cardiac sympathetic activity. Interestingly, the degree of obesity induced hypertension was augmented when mice were studied at thermonuetrality. The results suggest an important unrecognized role for vagal tone in the regulation of cardiovascular function in mice and support the need for considerable caution when using mouse models of obesity to examine regulation of cardiovascular function. We argue that mouse physiology studies should be performed in thermoneutral conditions.     

Ethanol vapor self-administration in adult C57BL/6J male mice

To determine if ethanol vapor is reinforcing, chambers with two nose-poke devices were used. First, C57BL/6J mice were trained to nose-poke at one (FR port) and then to hold a nose-poke for at least 1 s at the second (reward port) for 10% sucrose reinforcement. When mice held reward port nose-pokes for > or = 1 s on 95% of session trials, ethanol vapor (0.05%, w/v) or clean air replaced sucrose. In experiment 1, the FR requirement at the FR port was incremented from 1 to 8. Ethanol vapor (n=3) or clean air (n=3) was delivered for 1 s following a single nose-poke at the reward port after completing response requirements at the FR port. Nose-pokes at the FR port increased with increasing FR to maintain ethanol vapor intake, while clean air intake and its associated responding extinguished. In experiment 2, mice (n=4) controlled the duration of ethanol vapor delivery by providing vapor for as long as the mouse held a single poke in the reward port after completing response requirements at the FR port. Nose-pokes at the FR port increased with increasing FR to maintain ethanol vapor intake at the reward port. These findings indicate that ethanol vapor is reinforcing in adult C57BL/6J male mice.     

Distribution and excretion of 2,3,7,8-tetrachlorodibenzofuran in C57BL/6J and DBA/2J mice

The distribution and excretion of the toxic pollutant, 2,3,7,8-tetrachlorodibenzofuran (TCDF), was studied in male C57BL/6J and DBA/2J mice (22–29 g). [¹⁴C]TCDF was administered iv at a dose of 0.1 μmmol/kg. The liver was the major site of TCDF accumulation, with more TCDF in the livers of C57BL/6J mice compared to DBA/2J mice. TCDF had a half-life of approximately 1.8 days in the livers of both strains. At 7 hr and 1 day, respectively, radioactivity was redistributed to adipose tissue of C57BL/6J mice and DBA/2J mice. The terminal $\text{T}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ of TCDF in adipose tissue of C57BL/6J mice was 1.1 days, whereas it was 6.8 days in DBA/2J mice; the sixfold longer half-life in DBA/2J mice may be related to the approximately 36% greater adipose tissue content of this strain which may sequester more TCDF. More than 80 and 55% of the dose was excreted in the feces of C57BL/6J and DBA/2J mice, respectively, within 10 days as polar metabolites. The whole body half-life of TCDF was 2 days in C57BL/6J and 4 days in DBA/2J mice. Thus, DBA/2J mice sequester more of the TCDF dose in adipose tissue, accounting for a relatively slower rate of clearance and lower concentrations of TCDF at the putative target site(s) for toxic action.     

Genetic differences in intravenous cocaine self-administration between C57BL/6J and DBA/2J mice

In experiment 1, two different strains of mice [C57BL/6J (B6) and DBA/2J (D2)] were allowed to nosepoke for 5 µl intravenous (IV) infusions during 2-h daily sessions. Two nosepoke holes were available, only one of which was reinforced on an FR-3 schedule with a 10-s time-out indicated by a light inside the reinforced nosepoke hole. During the first nine sessions, infusions were saline. On subsequent sessions, mice acquired nosepoking for 0.5 mg/kg cocaine. Finally, all mice were extinguished by again receiving only saline infusions. Cocaine acted as a reinforcer in both strains. In experiment 2, different mice from the same two strains were allowed to acquire nosepoking for IV cocaine at one of three unit doses (0.5, 1.0, or 2.0 mg/kg). Although there were no effects of unit dose on rate of acquisition, B6 mice were faster in acquiring self-administration behavior than were D2 mice. Experiment 3 assessed behavior in the same mice, after acquisition had occurred. D2 mice nosepoked at a lower rate at asymptote than did B6 mice, but with a higher preference for the cocaine reinforced hole. Unit doses of cocaine were then manipulated within subjects, from 0.125 to 2.0 mg/kg per infusion. Higher doses yielded lower response rates than lower doses, both between and within subjects. Behavior in D2 mice relative to B6 mice also appeared to be shifted to the left of the dose-response curve measured within-subjects. Together, these findings indicate that although cocaine serves as a reinforcer in both strains, there are genetic differences in the pattern of cocaine self-administration between these two mouse strains.     

Genetic differences in 2-aminofluorene pharmacokinetics between intact C57BL/6J and A/J mice

Studies of genetically determined differences in arylamine acetylation with the model carcinogen 2-aminofluorene in C57BL/6J and A/J inbred mouse strains showed that individual differences in the pharmacokinetics of 2-aminofluorene were dependent on differences in 2-aminofluorene N-acetyltransferase activity in liver and blood. Elimination rates of 2-aminofluorene from blood of mice administered a single ip dose of 30, 50, or 100 mg/kg of 2-aminofluorene were dose-dependent in both strains. At a dose of 100 mg/kg, the average rate of 2-aminofluorene elimination was approximately three times faster in rapid acetylator (C57BL/6J) mice than in slow acetylator (A/J) mice (0.36 +/- 0.02 hr-1 vs. 0.12 +/- 0.02 hr-1), and that in B6AF1 mice was intermediate (0.24 +/- 0.02 hr-1) to the parental lines. These results support previous observations that acetylation of arylamines is controlled by intermediate dominant inheritance of two major alleles at a single locus. Comparison of the average rate of elimination of 2-aminofluorene from blood of the congenic mouse line, A.B6-NATr, (0.27 +/- 0.05 hr-1) which has the rapid acetylator allele placed on the A/J background provided evidence that modifying genes of the A/J mouse significantly reduced the effect of the rapid acetylator allele on the rate of 2-aminofluorene elimination. A trend was observed toward a greater apparent volume of distribution for 2-aminofluorene in A/J than in C57BL/6J mice.     

Accumbens Homer2 overexpression facilitates alcohol-induced neuroplasticity in C57BL/6J mice.

Homer proteins are integral components of the postsynaptic density that are necessary for alcohol-induced neuroplasticity within the nucleus accumbens (NAC). In this report, we describe the effects of chronic alcohol consumption upon NAC Homer expression and investigate the functional consequences of mimicking the alcohol-induced changes in Homer expression vis-à-vis alcohol-induced changes in NAC neurochemistry and behavior. Chronic alcohol consumption under continuous access (3 months; daily intake approximately 11.2+/-1.5 g/kg/day) produced a robust increase in NAC Homer2 protein levels that was apparent at 2 days, 2 weeks, and 2 months following withdrawal from alcohol drinking. The increased Homer2 expression was accompanied by a less enduring elevation in total mGluR1 and NR2b levels that were evident at 2 days and 2 weeks but not at the 2-month time point. Mimicking the alcohol-induced increase in Homer2 levels by viral transfection of NAC neurons in alcohol-preferring C57BL/6J inbred mice enhanced behavioral output for alcohol reinforcement and increased alcohol intake under both preprandial and postprandial conditions. Moreover, NAC Homer2 overexpression facilitated the expression of an alcohol-conditioned place preference, as well as the development of motor tolerance. Finally, NAC Homer2 overexpression facilitated NAC glutamate and dopamine release following an acute alcohol injection and augmented alcohol-induced dopamine and glutamate sensitization, but did not affect NAC gamma-aminobutyric acid levels. Thus, an upregulation in NAC mGluR-Homer2-N-methyl-D-aspartic acid receptor signaling appears to be an important molecular adaptation to alcohol that promotes neuroplasticity facilitating motivational drive for alcohol and the development of alcoholism-related behaviors.     

Decabromodiphenyl ether-induced PRKACA hypermethylation contributed to glycolipid metabolism disorder via regulating PKA/AMPK pathway in rat and L-02 cells

BDE-209 is the most prevalent congener of polybrominated diphenyl ethers and has high bioaccumulation in humans and animals. BDE-209 has been reported to disrupt glycolipid metabolism, but the mechanisms are still unclear. In this study, we found that BDE-209 induced liver tissue injury and hepatotoxicity, increased the glucose and total cholesterol levels in the serum of rats, and increased glucose and triglyceride levels in L-02 cells. BDE-209 exposure changed the PKA, p-PKA, AMPK, p-AMPK, ACC, and FAS expression in rats’ liver and L-02 cells. Moreover, BDE-209 induced PRKACA-1 hypermethylation in L-02 cells. AMPK activator (AICAR) inhibited the changes of p-AMPK, ACC, and FAS expression and elevation of glucose and triglyceride levels induced by BDE-209. DNA methylation inhibitor (5-Aza-CdR) reversed BDE-209 induced alters of PKA/AMPK/ACC/FAS signaling pathway. These results demonstrated that BDE-209 could disrupt the glycolipid metabolism by causing PRKACA-1 hypermethylation to regulate the PKA/AMPK signaling pathway in hepatocytes.     

C57BL/6J小鼠颈动脉粥样硬化斑块模型的建立

目的 探讨一种经济快速制作颈动脉粥样硬化斑块的方法.方法 30只C57BL/6J小鼠随机分为实验组(A组,24只)和对照组(C组,6只).A组采用颈动脉硅胶圈植入法建立颈动脉粥样硬化斑块模型.术后0、2、4、6周,检测甘油三酯(TG)、血清总胆固醇(TC)、低密度脂蛋白(LDL)及高密度脂蛋白(HDL)水平,HE染色检测颈动脉病理形态学的变化.结果 与C组相比,A组小鼠TC及LDL水平升高(P＜0.05),HDL水平降低(P＜0.05),小鼠淋巴细胞广泛浸润,内膜、中膜增厚,颈动脉斑块形成.结论 采用颈动脉硅胶圈植入法可快速制作C57BL/6J小鼠颈动脉粥样硬化斑块模型.