Gene therapy reduces ethanol intake in an animal model of alcohol dependence

Background:  Some gene polymorphisms strongly protect against the development of alcoholism. A large proportion of East Asians carry a protective inactivating mutation in aldehyde dehydrogenase (ALDH2*2). These subjects display high levels of blood acetaldehyde when consuming alcohol, a condition that exerts a 66 to 99% protection against alcohol abuse and alcoholism. Present knowledge allows the incorporation of therapeutic genes that can modify the expression of disease predisposing genes, an effect that can last from months to years. In line with the above, we have tested if inhibiting the expression of the aldehyde dehydrogenase gene ( ALDH2 ) by an anti- Aldh2 antisense gene can curtail the drive of alcohol-dependent animals to consume alcohol.
Methods:  Wistar-derived rats bred as high alcohol drinkers (UChB; Universidad de Chile Bibulous) were rendered alcohol dependent by a 2-month period of voluntary ethanol (10%) intake, subjected to a 3-day withdrawal period and further allowed access to 10% ethanol for only 1 hour each day. This condition results in a high ethanol intake (1.2 g/kg/60 min) which is 10 times higher than that of naïve UChB rats.
Results:  The single intravenous administration of an anti- Aldh2 antisense gene carried by an adenoviral vector reduced liver ALDH2 activity by 85% ( p  < 0.002) and inhibited voluntary ethanol intake by 50% (ANOVA p  < 0.005) for 34 days.
Conclusions:  This proof-of-principle study indicates that gene therapy approaches can be employed to achieve a long-term reduction of alcohol intake in alcohol-dependent animals and suggests that gene vectors may be developed as long-lasting therapeutic adjuncts for the treatment of alcoholism.     

Effects of alcohol consumption on the allergen-specific immune response in mice

Background:  There is evidence that chronic alcohol consumption impairs the T-helper 1 (Th1) lymphocyte-regulated cell-mediated immune response possibly favoring a Th2 deviation of the immune response. Moreover, a few epidemiological studies have linked alcohol consumption to allergen-specific IgE sensitization.
Objective:  To investigate the effects of alcohol consumption on the allergen-specific immune response in mice.
Methods:  BALB/cJBomTac mice were immunized intraperitoneally with ovalbumin (OVA) using a low dose sensitization protocol. Throughout the experiment, mice were kept on isocalorical liquid diets containing 0 to 6.2% ethanol. Evaluation of immunomodulatory effects of ethanol was based on measurements of total serum IgE, as well as OVA-specific IgE, IgG1, and IgG2a. Furthermore, levels of OVA-induced interleukin (IL)-4 and interferon- γ were determined in ex vivo splenocyte cultures.
Results:  Alcohol intake decreased the level of OVA-specific IgG2a in a dose-dependent manner, whereas high levels of alcohol markedly increased the level of total IgE, but not OVA-specific IgE. Th1 suppression was supported by the cytokine profile.
Conclusions:  Alcohol consumption induced a marked decrease in markers of the Th1-type allergen-specific immune response and an increase in total serum IgE. In this model, there was no effect of alcohol on OVA-specific IgE. Studies using other routes of immunization may be warranted.     

De novo cholesterol synthesis in three different animal models of diabetes

Summary Recent studies have demonstrated that cholesterol synthesis is increased two to threefold in the intestines of streptozotocin-induced diabetic rats. Cholesterol synthesis in tissues other than the intestines, including the liver, was not significantly altered by diabetes. In diabetic Chinese hamsters, cholesterol synthesis was increased 2.5-fold in both the small and large intestine. These observations are similar to our findings in diabetic rats and suggest that a stimulation of intestinal cholesterogenesis may be a uniform phenomenon in insulinopenic diabetes. In db/db mice, cholesterol synthesis was increased in both the liver and intestines but quantitatively the increase in hepatic cholesterogenesis was of much greater magnitude. Cholesterol feeding, which markedly inhibited hepatic cholesterol synthesis in both control and db/db mice, did not obliterate this difference in hepatic cholesterol synthesis. In ob/ob mice, the severity of the metabolic disturbances was less than that observed in db/db mice and no abnormalities in cholesterol synthesis were observed in animals ingesting a low cholesterol diet. However, in ob/ob mice fed a high cholesterol diet, hepatic cholesterol synthesis was increased. These observations suggest that in obese insulin resistant diabetic animals of milder severity, the abnormality in hepatic cholesterol synthesis manifests itself only when the animals are ingesting a high cholesterol diet. The results of this and previous studies suggest that in insulinopenic diabetes there is a stimulation of cholesterol synthesis that is localized to the intestines, whereas in obese, insulin-resistant diabetic animals, cholesterol synthesis is altered in the liver.     

Deletion of the fyn-kinase gene alters behavioral sensitivity to ethanol

BACKGROUND: An earlier study showed that deletion of the fyn-kinase gene enhanced sensitivity to ethanol's sedative hypnotic effects and suggested that this was associated with diminished fyn-kinase phosphorylation of NMDA receptors. The authors of that study speculated that this resulted in an inability of the null mutants to develop acute tolerance to ethanol, leading to the longer ethanol-induced sleep times. However, in vivo acute tolerance to ethanol was not examined directly. METHODS: To address the role of fyn-kinase in mediating acute tolerance, as well as sensitivity to several other behavioral effects of ethanol, we studied an independently generated population of fyn null mutant and wild-type mice. RESULTS: Homozygous mutants exhibited longer ethanol sleep times that could not be attributed to differences in initial sensitivity, and impaired acute tolerance to the motor incoordinating effects of ethanol as measured by using the stationary dowel, but not the rotarod. Fyn-kinase null mutants were more sensitive to the anxiolytic effects of ethanol when tested using the elevated plus maze, and males displayed a lower preference for ethanol in a two-bottle choice paradigm. Finally, mutant and wild-type mice did not differ in sensitivity to the hypothermic effects of ethanol. The genotypes also did not differ in blood-ethanol clearance, eliminating a metabolic explanation for these behavioral differences. CONCLUSIONS: These results show that fyn-kinase modulates acute tolerance to ethanol and suggest a role for fyn in mediating ethanol's anxiolytic and reinforcing properties.     

Sources of plasma glucose and liver glycogen in fasted ob/ob mice

Abstract Alterations in intrahepatic carbohydrate fluxes in ob/ob mice and the effects of acute leptin administration were studied in vivo by use of a dual-isotope tracer infusion. Metabolic sources of plasma glucose (gluconeogenesis (GNG) and glycogenolysis) and hepatic glycogen (GNG, direct synthesis and pre-existing) were determined in 20-h-fasted mice infused with [2-13C1]glycerol and [U13C6]glucose for 3 h. Total glucose output (TGO) and the rate of appearance (Ra) of plasma glycerol were measured by isotope dilution. GNG, the direct pathway of hepatic glycogen synthesis and hepatic triose-phosphate flux were determined by mass isotopomer distribution analysis (MIDA). Serum glucose, insulin, leptin and liver glycogen concentrations were also measured. After a 24-h fast, ob/ob mice had 2-fold higher TGO, 2.5-fold elevated liver glycogen content and markedly higher glycogenolytic flux to glucose, absolute GNG and direct glycogen synthesis rates (10-fold increased) compared to the control group. Ob/ob mice also had elevated triose-phosphate flux compared to controls (40 vs. 22 mg/kg lean body mass/min). A model of intrahepatic flux distributions in control and ob/ob mice is presented. In summary, elevated fasting plasma glucose concentrations are due to increased TGO in ob/ob mice, which is maintained by both increased GNG and increased glycogenolysis. Furthermore, the ob/ob mice have major alterations in fasting hepatic carbohydrate fluxes into triose-phosphate pools and glycogen. We support the model that actions of leptin on hepatic glucose metabolism require insulin or other factors.     

Effects of neuropeptide Y on sucrose and ethanol intake and on anxiety-like behavior in high alcohol drinking (HAD) and low alcohol drinking (LAD) rats

BACKGROUND: In a previous study, neuropeptide Y (NPY) administered into the lateral ventricles decreased ethanol intake in alcohol-preferring (P) rats but not in alcohol-nonpreferring (NP) or unselected Wistar rats. The purpose of the present investigation is to extend these findings in selectively-bred high-alcohol-drinking (HAD)1 and low-alcohol-drinking (LAD)1 rats by examining the effects of intracerebroventricularly administered NPY on the elevated plus maze test of anxiety and on ethanol and sucrose intake. METHODS: Female HAD1 and LAD1 rats were surgically implanted with cannula into the lateral ventricle. Following recovery, a test of anxiety was conducted in which the rats (n = 12-13/group) received either artificial cerebrospinal fluid (aCSF) or NPY (10 microg) 10 min prior to a 5-min test on an elevated plus maze. Following anxiety testing, 11 HAD and 11 LAD rats were trained to self-administer ethanol (8% w/v), and 5 HAD and 8 LAD rats were trained to self-administer sucrose (2.5%) during daily 2-hr sessions. A within-subject design was used in which the rats were pretreated once a week with aCSF, 5 microg NPY, or 10 microg NPY prior to the drinking sessions. RESULTS: HAD and LAD rats treated with aCSF did not differ in time spent in open arms of the plus maze. NPY increased time spent on the open arms to similar degrees in both rat lines. HAD rats consumed more ethanol and sucrose than LAD rats. NPY increased sucrose intake in both rat lines. However, the same doses of NPY reduced ethanol intake in HAD but not in LAD rats. CONCLUSION: The plus maze results indicated that selective breeding for high and low alcohol preference in the HAD1 and LAD1 rats, respectively, did not yield differences in anxiety-like behavior and in response to the anxiolytic effects of NPY. The increases in sucrose intake were consistent with the known orexigenic effects of NPY. The decreased ethanol intake following NPY administration in HAD rats was similar to previous observations with P rats and is consistent with the hypothesis that ethanol intake and NPY activity may be inversely related.     

Pharmacological profiles of a novel protein tyrosine phosphatase 1B inhibitor,JTT‐551

Aim: Protein tyrosine phosphatase 1B (PTP1B), a negative regulator of insulin signalling, is a novel therapeutic target for type 2 diabetes mellitus. We evaluated in vitro and in vivo the pharmacological profiles of a new PTP1B inhibitor, JTT‐551: monosodium ({[5‐(1,1‐dimethylethyl)thiazol‐2‐yl]methyl} {[(4‐{4‐[4‐(1‐propylbutyl)phenoxy]methyl}phenyl)thiazol‐2‐yl]methyl}amino)acetate. Methods: PTP1B inhibitory activity and the inhibition mode were assayed with p‐nitrophenyl phosphate as a substrate, and the selectivity of JTT‐551 against other PTPs, including T‐cell protein tyrosine phosphatase (TCPTP), CD45 protein tyrosine phosphatase (CD45) and leucocyte common antigen‐related protein tyrosine phosphatase (LAR), was evaluated. Glucose uptake with JTT‐551 treatment was evaluated in L6 rat skeletal myoblasts (L6 cells). In the in vivo study, we investigated the effects on insulin receptor (IR) phosphorylation and blood chemical parameters with JTT‐551 administration in ob/ob mice and db/db mice. Results: JTT‐551 showed an inhibitory effect on PTP1B with a Ki value of 0.22 µM, and a mixed‐type inhibition mode. Ki values of TCPTP, CD45 and LAR were 9.3, 30 or higher and 30 or higher µM, respectively, and JTT‐551 exhibited clear selectivity against the other PTPs. Moreover, JTT‐551 increased the insulin‐stimulated glucose uptake in L6 cells. A single administration of JTT‐551 in ob/ob mice enhanced the IR phosphorylation of liver and reduced the glucose level. In db/db mice, chronic administration showed a hypoglycaemic effect without an acceleration of body weight gain. Conclusions: JTT‐551, a newly developed PTP1B inhibitor, improves glucose metabolism by enhancement of insulin signalling and could be useful in the treatment of type 2 diabetes mellitus.     

Laboratory tests for acute alcohol consumption: results of the WHO/ISBRA Study on State and Trait Markers of Alcohol Use and Dependence

BACKGROUND: The WHO/ISBRA Study on State and Trait Markers of Alcohol Use and Dependence aimed partly to evaluate the overall performance and cross-national validity of traditional and new biological markers of alcohol use and abuse. This article focused on the sensitivity and specificity of ethanol and methanol concentrations in plasma, and the 5-hydroxytryptophol (5HTOL) to 5-hydroxyindole-3-acetic acid (5HIAA) ratio in urine, as laboratory tests to identify acute alcohol consumption. Comparison was made with self-reported drinking levels. METHODS: Subjects were recruited in Australia, Brazil, Canada, Finland, and Japan. They were interviewed thoroughly about their alcohol consumption habits, by using the standardized WHO/ISBRA Interview Schedule, and were classified into four categories: nondrinkers, light/moderate drinkers, heavy drinkers (> or =210 g ethanol/week for men, and > or =140 g/week for women), or patients who were receiving treatment for alcohol dependence. Ethanol and methanol determinations in plasma were carried out by headspace gas chromatography. Urinary concentrations of 5HTOL and 5HIAA were determined by using gas chromatography-mass spectrometry and high-performance liquid chromatography, respectively. RESULTS: The baseline levels (in nondrinkers) for methanol and the 5HTOL/5HIAA ratio did not differ markedly between the five populations, except for a considerably higher, but probably artifactual, methanol level in the Finnish plasma samples. Moreover, there were no apparent age or sex differences. The urinary 5HTOL/5HIAA ratio was the most, and ethanol the least, sensitive indicator of recent alcohol consumption, and this was true for the different drinking categories as well as for the five study populations. The highest frequency of elevated test results was observed among those classified as heavy drinkers (e.g., 38% were positive for 5HTOL/5HIAA). However, elevated values also were obtained in nondrinkers and in drinking subjects who denied any intake of alcohol within 2 days before the interview and blood/urine sampling, which suggested a low accuracy of self-reports of alcohol consumption in certain individuals. CONCLUSIONS: The present investigation demonstrated that plasma ethanol and methanol and urinary 5HTOL/5HIAA provide useful exclusion markers for any study of biological parameters that are affected by previous acute ethanol intoxication. The major advantage of methanol and 5HTOL/5HIAA over ethanol is that they can detect recent alcohol consumption even several hours after the ethanol is no longer measurable. The results suggest that the cutoff limits to be used for these markers are not dependent on the country or population to be studied.     

Hybrid C57BL/6J x FVB/NJ mice drink more alcohol than do C57BL/6J mice

BACKGROUND: From several recent strain surveys (28 strains: Bachmanov et al., personal communication; 22 strains: Finn et al., unpublished), and from data in >100 other published studies of 24-hr two-bottle ethanol preference, it is known that male C57BL/6 (B6) mice self-administer about 10-14 g/kg/day and that female B6 mice self-administer about 12-18 g/kg/day. No strain has been found to consume more ethanol than B6. In one of our laboratories (Texas), we noted a markedly greater intake of ethanol in an F1 hybrid of B6 and FVB/NJ (FVB) mice. METHODS: To confirm and extend this finding, we repeated the study at another site (Portland) using concentrations up to 30% ethanol and also tested B6xFVB F1 mice in restricted access drinking procedures that produce high levels of alcohol intake. RESULTS: At both sites, we found that B6xFVB F1 mice self-administered high levels of ethanol during two-bottle preference tests (females averaging from 20 to 35 g/kg/day, males 7-25 g/kg/day, depending on concentration). F1 hybrids of both sexes drank significantly more 20% ethanol than both the B6 and FVB strains. Female F1 hybrids also drank more 30% ethanol. In the restricted access tests, ethanol consumption in the F1 hybrids was equivalent to that in B6 mice. CONCLUSIONS: These data show that this new genetic model has some significant advantages when compared to existing inbred strains, and could be used to explore the genetic basis of high ethanol drinking in mice.     

Anxiety and sensitivity to ethanol and pentobarbital in alcohol withdrawal seizure-prone and withdrawal seizure-resistant mice

BACKGROUND: Withdrawal Seizure-Prone (WSP) and Withdrawal Seizure-Resistant (WSR) mice were selectively bred for high and low handling-induced convulsions, respectively, after chronic ethanol treatment. Withdrawal severity is one factor that may contribute to the development of alcoholism and/or substance abuse, and anxiety is another. We sought to explore whether these factors are genetically related. METHODS: WSP and WSR mice of two replicate pairs of selected lines were tested for anxiety-related behaviors on the canopy stretched-attend-posture apparatus 20 min after intraperitoneal injection of ethanol (2 g/kg, 20% v/v), pentobarbital (20 mg/kg), or an equivalent volume of saline. Dependent measures of anxiety included number of stretched attend postures (SAP) and time spent in the exposed area of the apparatus. Number of line crossings, which measures overall activity, was also scored. RESULTS: WSP mice given saline exhibited more SAP than WSR mice given saline, which indicated greater baseline anxiety. Ethanol and pentobarbital both reduced SAP and increased time spent in the exposed area of the apparatus, which indicated that both drugs exerted an anxiolytic effect. Despite baseline differences in SAP between selected lines, both anxiolytic drugs reduced SAP to similar levels in WSP and WSR mice. CONCLUSIONS: These results support the hypothesis that WSP mice are more sensitive than WSR mice to the anxiety-reducing effects of ethanol and pentobarbital. Some genes that influence this difference are likely to be the same as those that influence ethanol withdrawal severity. Thus, higher basal anxiety and greater genetic sensitivity to anxiolytic drug effects may relate to a greater genetic predisposition to the development of severe alcohol withdrawal signs.     

Factors influencing elevated ethanol consumption in adolescent relative to adult rats

BACKGROUND: Many teenagers report frequent alcohol use during the adolescent period. Animal models may be an important tool for exploring factors that contribute to alcohol consumption during this critical period. METHODS: Using a 24-hour, free-access, two-bottle-choice procedure between water and a sweetened solution with or without ethanol in nondeprived rats, the present series of experiments examined the contribution of a variety of contextual and experimental variables (i.e., isolate-housing versus pair-housing, type of sipper tube, caloric value of solution, prior experimental perturbations) on alcohol consumption in both adolescent and adult Sprague-Dawley rats. RESULTS: Ethanol consumption was particularly magnified among adolescent rats using ball bearing-containing ball-point (BP) sipper tubes, with this exacerbated intake not due to caloric content of the ethanol solution. Isolation housing for 12 days did not alter ethanol consumption of adolescents relative to their socially housed counterparts while suppressing consumption of isolated adults. An examination of differences in the relative magnitude of adolescent ethanol consumption across experiments in this series revealed that ethanol intake among adolescents was elevated not only by the inclusion of BP sipper tubes but also by staggering the timing of isolate housing relative to the presentation of the novel ethanol solution. CONCLUSIONS: The results of this experimental series demonstrate that adolescent animals consume significantly more ethanol than adult animals under a variety of home cage continuous-access circumstances, with the relatively greater intake of adolescents further magnified by a number of test conditions. Subtle experimental details often thought to be innocuous can have a substantial impact on overall amount of voluntary ethanol consumption observed in both adolescent and adult animals.     

大黄酸对db/db小鼠糖尿病肾病疗效的观察

目的 :探讨大黄酸对 2型糖尿病模型db/db小鼠糖尿病肾病的疗效及可能机制。　 方法 :以C5 7BL/KsJdb/db糖尿病小鼠为研究对象 ,以db/m小鼠为正常对照 ,大黄酸 12 0mg/ (kg·d)灌胃 ,连续 12周。定期观察血糖、血生化及血胰岛素变化 ,同时测定 2 4h尿白蛋白排泄量。实验结束时 ,宰杀小鼠 ,留取肾组织 ,作病理形态学检查、免疫组化及定量分析。　 结果 :db/db小鼠在实验开始时 ,已表现出明显肥胖 ,高血糖 ,高胰岛素及高脂血症 ,并出现白蛋白尿 ,随着病程延长 ,这些改变更加明显 ,并逐渐达到顶峰 ,胰岛素水平在实验后期迅速下降 ,同时肾功能受到损害 ,血肌酐明显上升。病理检查发现db/db小鼠未治疗组肾小球明显肥大 ,系膜区扩张 ,基膜增厚 ,细胞外基质 (ECM)合成增加 ,免疫球蛋白沉积增加。经大黄酸治疗 12周后 ,高脂血症被明显纠正 ,血糖轻微下降 ,2 4h尿白蛋白排泄量减少 ,肾功能得到保护。病理改变也明显减轻 ,ECM沉积减少 ,系膜区与丝球体面积比值明显减小 ,免疫球蛋白沉积被大部清除。　 结论 :大黄酸可以明显改善db/db小鼠糖尿病肾病的损害 ,延缓肾功能减退。     

6-beta-naltrexol reduces alcohol consumption in rats

BACKGROUND: In humans, 6-beta-naltrexol is the major metabolite of naltrexone, and its effectiveness at suppressing alcohol consumption in any species has not been previously investigated. Naltrexone is an opiate antagonist that reduces excessive drinking in many species, including humans with alcohol dependence. Whether 6-beta-naltrexol is an active metabolite that contributes to the efficacy of naltrexone remains unknown. METHODS: Placebo and four doses of 6-beta-naltrexol were given by intraperitoneal injection to outbred Wistar rats and alcohol consumption was measured using a limited access model. RESULTS: 6-beta-Naltrexol reduced alcohol consumption in a dose-dependent manner. At doses 7.5, 12.5, and 25 mg/kg, 6-beta-naltrexol significantly decreased consumption of a 6% ethanol solution compared with saline control groups. CONCLUSIONS: These data suggest that there may be a potential clinical use for 6-beta-naltrexol in recovering alcoholics.     

Blockade of endothelin receptors markedly reduces atherosclerosis in LDL receptor deficient mice: role of endothelin in macrophage foam cell formation

OBJECTIVE: We evaluated the direct effects of long-term blockade of ET(A) and ET(B) receptors using a mixed endothelin (ET) receptor antagonist, LU224332, in the low density lipoprotein receptor (LDL-R) knockout mouse model of atherosclerosis. METHODS: Four groups of LDL-R deficient mice were studied: control mice fed normal chow (group I); mice fed a high cholesterol (HC, 1.25%) diet alone (group II), HC fed animals treated with LU224332 (group III); and mice fed normal chow treated with the LU compound (group IV). All treatments were continued for 8 weeks at which time the animals were sacrificed and the aortae were removed and stained with oil red O. Atherosclerotic area (AA) was determined by quantitative morphometry and normalized relative to total aortic area (TA). RESULTS: Cholesterol feeding resulted in a marked increased in total plasma cholesterol ( approximately 15 fold) and widespread aortic atherosclerosis (AA/TA: group I: 0.013+/-0.007; group II: 0.33+/-0. 11; P<0.001). Atherosclerotic lesions were characterized by immunohistochemistry as consisting mainly of macrophages which also showed high levels of ET-1 expression. Treatment with ET antagonist significantly reduced the development of atherosclerosis (AA/TA: group III: 0.19+/-0.07, P<0.01 vs. group II), without altering plasma cholesterol levels and blood pressure. The direct effect of LU224332 on macrophage activation and foam-cell formation was determined in vitro using a human macrophage cell line, THP-1. Treatment of the THP-1 cells with LU224332 significantly reduced cholesterol ester and triacylglycerol accumulation and foam-cell formation on exposure to oxidized LDL (P<0.01 and P<0.05, respectively). CONCLUSION: We conclude that a nonselective ET receptor antagonist substantially inhibited the development of atherosclerosis in a genetic model of hyperlipidemia, possibly by inhibiting macrophage foam-cell formation, suggesting a role for these agents in the treatment and prevention of atherosclerotic vascular disease.     

A technique for the isolation of highly viable pancreatic B-cells fromob/ob mice

Summary A method has been developed to prepare free islet cells in suspension from adultob/ob-mice. About 200 collagenase-isolated pancreatic islets were pooled in 4 ml of calcium-free Krebs-Ringer-HEPES buffer supplemented with 1 mM EGTA and 10 μg/ml DNAase. The islets were gently shaken in a water-bath for 10 min at 30°C. Then, the cell suspension was filtered through a nylon screen and centrifuged through ice-cold, dense albumin. The isolated cells, of which more than 99% were B-cells, appeared well preserved both in light- and electron-microscopy. Out of the isolated cells, 7.1±0.5% took up Evans Blue and were thus considered non-viable.     

大黄酸和苯那普利联合治疗db/db糖尿病小鼠的疗效观察

目的:观察大黄酸和苯那普利对糖尿病db/db小鼠肾脏损伤的保护作用,比较二者疗效的差别,同时探讨大黄酸联合苯那普利治疗2型糖尿病肾病的疗效。方法:8周龄的db/db和db/m小鼠分为五组:A:db/m正常小鼠对照组;B:db/db糖尿病小鼠对照组;C:db/db糖尿病小鼠大黄酸[150mg/(kg·d)]治疗组;D:db/db糖尿病小鼠苯那普利[10mg/(kg·d)]治疗组;E:大黄酸[150mg/(kg·d)]联合苯那普利[10mg/(kg·d)]治疗组。于不同治疗时间(4周、8周、12周)测定各组体重、血糖、血脂(胆固醇、三酰甘油、高密度脂蛋白、低密度脂蛋白)、血肌酐、24h尿白蛋白水平。肾组织病理切片行HE、PAS染色,采用图像分析软件对肾小球病理形态学改变进行定量分析。免疫病理观察肾组织转化生长因子(transforminggrowthfactor-β,TGF-β)以及纤维粘连蛋白(fibronectin,FN)的表达,并行半定量评分。结果:大黄酸组在治疗8周时体重、血糖、胆固醇、低密度脂蛋白、24h尿白蛋白排泄较糖尿病对照组均有明显下降(P<0·05),治疗12周时肾小球肥大、基质增生较糖尿病对照组明显改善,TGF-β、FN在肾小球中表达下调;苯那普利组治疗8周时24h尿白蛋白排泄较糖尿病对照组明显下降(P<0·05),治疗12周同样可减轻肾组织病变;大黄酸联合苯那普利组治疗第4周就能明显降低胆固醇、减轻尿白蛋白排泄,并且在治疗12周时血肌酐水平较糖尿病对照组明显下降(P<0·05),肾小球肥大以及基质增生较糖尿病对照组改善更为明显,同时TGF-β以及FN的表达下调更为显著。结论:大黄酸可改善db/db小鼠的肥胖程度、降低血糖、脂代谢紊乱,同时能降低尿白蛋白的排泄、改善肾功能,明显减轻db/db小鼠的肾脏病变;苯那普利同样可降低尿白蛋白排泄,改善肾功能,减轻肾组织病理改变。大黄酸和苯那普利联合治疗较单独用药更早的降低尿白蛋白排泄和改善血脂水平,同时改善肾功能和减轻肾组织病变的疗效也更加明显,大黄酸和苯那普利联合治疗疗效明显优于二者单独用药。     

Effects of alcohol deprivation on alcohol consumption using a sipper-tube procedure

BACKGROUND: When rats with prior experience drinking ethanol solutions are deprived of ethanol for various time periods, a transitory increase in alcohol consumption is observed when ethanol solutions are again made available. This has been termed the alcohol deprivation effect (ADE). The ADE has been observed in limited-access operant procedures in which small dippers of ethanol are presented following completion of a lever press requirement. However, it has not been determined if the effect occurs in an operant model of ethanol self-administration that separates the ethanol-seeking responding from the consummatory drinking (the sipper procedure). METHODS: Rats were initiated to drink ethanol from a sipper tube using the sucrose-substitution procedure. Once initiated, the rats had to make 30 lever presses to gain access to a sipper-tube containing the ethanol solution for 20 min. The effects of 2-3 days, 7 days, and 14 days of ethanol deprivation were examined on ethanol consumption and extinction responding (seeking response). RESULTS: There were no effects of deprivation on intake at any deprivation period examined. Contrary to expectations, the alcohol-seeking response as measured by extinction responding was decreased after 7 and 14 days of deprivation. CONCLUSIONS: The data from this study and others using the limited access operant procedures suggest that the ADE may be more related to consummatory control (i.e., loss of control) and not to ethanol-seeking behaviors (i.e., craving).     

Role of genotype in the development of locomotor sensitization to alcohol in adult and adolescent mice: comparison of the DBA/2J and C57BL/6J inbred mouse strains

Background: Animal models that explore differential sensitivity to the effects of acute and repeated exposure of alcohol (ethanol) may be influenced by both the developmental and genetic profile of the population. Therefore, we sought to compare the influence of ontogeny on sensitivity to ethanol‐induced locomotor stimulation and on the induction of locomotor sensitization to this effect across 2 inbred strains of mice; the ethanol consuming C57BL/6J and the ethanol avoiding DBA/2J strains. Methods: C57BL/6J and DBA/2J adults (postnatal day [PD] 60 to 80) and adolescents (PD 30 ± 2) were assessed for basal activity, acute response to 2.0 g/kg ethanol, and the expression of locomotor sensitization following repeated administration of 2.5, 3.0, or 3.5 g/kg ethanol. Results: Basal activity was different across development for the C57BL/6J, but not DBA/2J, with adult B6 mice showing persistently greater baseline activity. Adolescents of both strains were more sensitive than adults to acute ethanol‐induced locomotor stimulation; adults exhibited a decrease in their acute response across the testing session. Adolescent DBA/2J mice developed less ethanol sensitization compared to adults, with significant sensitization observed only following repeated administration of the lowest ethanol dose (2.5 g/kg), whereas DBA/2J adults sensitized to all doses. Age did not influence the development of ethanol sensitization for the C57BL/6J strain, as both adults and adolescents displayed a sensitized response following all ethanol doses. Conclusions: These results suggest that the developmental pattern of locomotor sensitivity to ethanol is unique to the genotypic profile of the animal model.     

Ability of baclofen in reducing alcohol intake and withdrawal severity: I--Preclinical evidence

BACKGROUND: The similarities between the pharmacological effects of the gamma-aminobutyric acid receptor agonist, baclofen, and the alcohol-substituting agent, gamma-hydroxybutyric acid, led us to investigate whether baclofen was capable of reducing (a) ethanol withdrawal syndrome in ethanol-dependent rats and (b) voluntary ethanol intake in ethanol-preferring rats. METHODS: In experiment 1, Wistar rats were rendered physically dependent on ethanol by the repeated administration of intoxicating doses of ethanol for 6 consecutive days. Baclofen was acutely administered intraperitoneally at doses of 10, 20, and 40 mg/kg. In experiment 2, baclofen (0, 2.5, 5, and 10 mg/kg, intraperitoneally) was administered once a day for 14 consecutive days to ethanol-preferring sP rats that had continuous access to ethanol (10%, v/v) and water under the two-bottle free choice regimen. RESULTS: In experiment 1, baclofen dose-dependently decreased the intensity of ethanol withdrawal signs; furthermore, 20 mg/kg of baclofen protected from audiogenic seizures in ethanol-withdrawn rats. In experiment 2, baclofen selectively and dose-dependently reduced voluntary ethanol intake; a compensatory increase in water intake left total fluid intake virtually unchanged. CONCLUSIONS: These results are in close agreement with those of a preliminary clinical study and suggest that baclofen may constitute a novel therapeutic agent for alcoholism.     

Decreased deformability of erythrocytes in hyperglycaemic non-inbred ob/ob mice

Summary The deformability of erythrocytes from non-inbred ob/ob mice and lean controls was analyzed by filtration through Nuclepore polycarbonate under constant pressure. At the age of 1–2 months there was no difference in erythrocyte filtrability between the two types of mice, whereas from 3 months the ob/ob mouse erythrocytes exhibited a markedly decreased deformability. The filtrability of erythrocytes was sensitive to osmotic pressure (NaCl or glucose). However, the difference between normal and ob/ob mouse of erythroyctes was not due to acute osmotic effects of the hyperglycaemia in the ob/ob mice. When filtration was performed in the same glucose concentration as that recorded in the blood of the erythrocyte-donor animal, the difference in filtrability between adult normal and ob/ob mice remained large and significant (p < 0.01). Moreover, the most pronounced hyperglycaemia occurred in young ob/ob mice with normal erythrocyte filtrability. It is suggested that non-inbred ob/ob mice are a useful model for studying the damaging influence of diabetes on erythrocyte deformability.