The Development of a Preference for Cocaine over Food Identifies Individual Rats with Addiction-Like Behaviors

Rationale

Cocaine dependence is characterized by compulsive drug taking that supercedes other recreational, occupational or social pursuits. We hypothesized that rats vulnerable to addiction could be identified within the larger population based on their preference for cocaine over palatable food rewards.

Objectives

To validate the choice self-administration paradigm as a preclinical model of addiction, we examined changes in motivation for cocaine and recidivism to drug seeking in cocaine-preferring and pellet-preferring rats. We also examined behavior in males and females to identify sex differences in this “addicted” phenotype.

Methods

Preferences were identified during self-administration on a fixed-ratio schedule with cocaine-only, pellet-only and choice sessions. Motivation for each reward was probed early and late during self-administration using a progressive-ratio schedule. Reinstatement of cocaine- and pellet-seeking was examined following exposure to their cues and non-contingent delivery of each reward.

Results

Cocaine preferring rats increased their drug intake at the expense of pellets, displayed increased motivation for cocaine, attenuated motivation for pellets and greater cocaine and cue-induced reinstatement of drug seeking. Females were more likely to develop cocaine preferences and recidivism of cocaine- and pellet-seeking was sexually dimorphic.

Conclusions

The choice self-administration paradigm is a valid preclinical model of addiction. The unbiased selection criteria also revealed sex-specific vulnerability factors that could be differentiated from generalized sex differences in behavior, which has implications for the neurobiology of addiction and effective treatments in each sex.     

Acute Phase IL-10 Plasma Concentration Associates with the High Risk Sources of Cardiogenic Stroke

Background

Etiological assessment of stroke is essential for accurate treatment decisions and for secondary prevention of recurrence. There is evidence that interleukin-10 (IL-10) associates with ischemic stroke. The aim of this prospective study was to assess the levels of IL-10 in ischemic stroke with unknown or suspected cardiogenic etiology, and evaluate the correlation between IL-10 plasma concentration and the number of diagnosed high risk sources for cardioembolism.

Methods

A total of 141 patients (97 males; mean age 61±11 years) with acute ischemic stroke with unknown etiology or suspected cardiogenic etiology other than known atrial fibrillation (AF) underwent imaging investigations to assess high risk sources for cardioembolic stroke established by the European Association of Echocardiography (EAE). IL-10 was measured on admission to the hospital and on a three month follow-up visit.

Results

Acute phase IL-10 concentration was higher in patients with EAE high risk sources, and correlated with their number (p<0.01). In patients with no risk sources (n = 104), the mean IL-10 concentration was 2.7±3.1 ng/L (range 0.3–16.3 ng/L), with one risk source (n = 26) 3.7±5.5 ng/L (0.3–23.6 ng/L), with two risk sources (n = 10) 7.0±10.0 ng/L (1.29–34.8 ng/L) and with three risk sources (n = 1) 37.2 ng/L. IL-10 level was not significantly associated with cerebral infarct volume, presence of previous or recent myocardial infarction, carotid/vertebral artery atherosclerosis, paroxysmal AF registered on 24-hour ECG Holter monitoring or given intravenous thrombolytic treatment.

Conclusion

IL-10 plasma concentration correlates independently with the number of EAE cardioembolic risk sources in patients with acute stroke. IL-10 may have potential to improve differential diagnostics of stroke with unknown etiology.     

Flagellin Treatment Prevents Increased Susceptibility to Systemic Bacterial Infection after Injury by Inhibiting Anti-Inflammatory IL-10+ IL-12- Neutrophil Polarization

Severe trauma renders patients susceptible to infection. In sepsis, defective bacterial clearance has been linked to specific deviations in the innate immune response. We hypothesized that innate immune modulations observed during sepsis also contribute to increased bacterial susceptibility after severe trauma. A well-established murine model of burn injury, used to replicate infection following trauma, showed that wound inoculation with P. aeruginosa quickly spreads systemically. The systemic IL-10/IL-12 axis was skewed after burn injury with infection as indicated by a significant elevation in serum IL-10 and polarization of neutrophils into an anti-inflammatory (“N2”; IL-10⁺ IL-12⁻) phenotype. Infection with an attenuated P. aeruginosa strain (ΔCyaB) was cleared better than the wildtype strain and was associated with an increased pro-inflammatory neutrophil (“N1”; IL-10⁻IL-12⁺) response in burn mice. This suggests that neutrophil polarization influences bacterial clearance after burn injury. Administration of a TLR5 agonist, flagellin, after burn injury restored the neutrophil response towards a N1 phenotype resulting in an increased clearance of wildtype P. aeruginosa after wound inoculation. This study details specific alterations in innate cell populations after burn injury that contribute to increased susceptibility to bacterial infection. In addition, for the first time, it identifies neutrophil polarization as a therapeutic target for the reversal of bacterial susceptibility after injury.     

Magnetic Resonance Imaging Determined Visceral Fat Reduction Associates with Enhanced IL-10 Plasma Levels in Calorie Restricted Obese Subjects

Background

Obesity is characterized by a low grade chronic inflammation state. Indeed circulating pro-inflammatory cytokines, such as TNF-α and IL-6, are elevated in obese subjects, while anti-inflammatory cytokines, such as IL-10, appear to be reduced. Cytokines profile improves after weight loss, but how visceral or subcutaneous fat loss respectively affect pro- or anti-inflammatory cytokines plasma levels has not been precisely assessed. Therefore in the present study we correlated changes in circulating cytokine profile with quantitative changes in visceral and subcutaneous adipose tissue depots measured by an ad hoc Magnetic Resonance Imaging (MRI) protocol before and after weight loss.

Materials and Methods

In 14 obese subjects, MRI determination of visceral and subcutaneous fat and plasma glucose, insulin, TNF-α IL-6, and IL-10 measurements were performed before and after a caloric restriction induced weight loss of at least 5% of the original body weight.

Results

Weight loss improved insulin sensitivity (QUICKI Index: 0.35±0.03 vs 0.37±0.04; P<0.05), increased IL-10 (3.4±1.9 vs 4.6±1.0 pg/mL; P<0.03), and reduced TNF-α and IL-6 plasma levels (2.5±1.3 vs 1.6±1.5 pg/mL, P<0.0015, 2.3±0.4 vs 1.6±0.6 pg/mL, P<0.02 respectively). A significant correlation was observed between the amount of visceral fat loss and the percentage reduction in both TNF-α (r = 0.56, p<0.05) and IL-6 (r = 0.19 p<0.05) plasma levels. In a multiple regression analysis, the amount of visceral fat loss independently correlated with the increase in IL-10 plasma levels.

Conclusion

The reduction in visceral adipose tissue is the main driver of the improved inflammatory profile induced by weight loss.     

IL-10基因多态性与子宫内膜异位症易感性的相关性研究

目的:探究白细胞介素-10(IL-10)基因多态性与子宫内膜异位症(EMs)易感性的相关性。方法:选取87例经病理组织学证实为EMs患者,对照组为100例健康女性,应用聚合酶链反应-限制性片段长度多态性(PCR-RFLP)分析方法,对两组妇女IL-10-1082、-819和-592位点的基因行多态性分析。结果:与对照组相比,EMs组-1082G/A位点等位基因及基因频率无差异(P0.05),-819 T/C和-592A/C位点等位基因或基因型频率较高(P0.05);与Ⅰ-Ⅱ期EMs患者相比,Ⅲ-Ⅳ期EMs患者-819T/C和-592A/C位点等位基因或基因型频率显著较高(P0.01)。结论:IL-10基因在-819T/C以及-592A/C位点的多态性与EMs的易感性有显著相关性。     

Plasma Cytokine Profile in Tropical Endomyocardial Fibrosis: Predominance of TNF-a,IL-4 and IL-10

Background

The participation of immune/inflammatory mechanisms in the pathogenesis of tropical endomyocardial fibrosis (EMF) has been suggested by the finding of early blood and myocardial eosinophilia. However, the inflammatory activation status of late-stage EMF patients is still unknown.

Methodology/Principal findings

We evaluated pro- and anti-inflammatory cytokine levels in plasma samples from late stage EMF patients. Cytokine levels of Tumor Necrosis Factor (TNF)-α, Interferon (IFN)-γ, Interleukin (IL)-2, IL-4, IL-6, and IL-10 were assayed in plasma samples from 27 EMF patients and compared with those of healthy control subjects. All EMF patients displayed detectable plasma levels of at least one of the cytokines tested. We found that TNF-α, IL-6, IL-4, and IL-10 were each detected in at least 74% of tested sera, and plasma levels of IL-10, IL-4, and TNF-α were significantly higher than those of controls. Plasma levels of such cytokines positively correlated with each other.

Conclusions/Significance

The mixed pro- and anti-inflammatory/Th2circulating cytokine profile in EMF is consistent with the presence of a persistent inflammatory stimulus. On the other hand, the detection of increased levels of TNF-α may be secondary to the cardiovascular involvement observed in these patients, whereas IL-4 and IL-10 may have been upregulated as a homeostatic mechanism to buffer both production and deleterious cardiovascular effects of pro-inflammatory cytokines. Further studies might establish whether these findings play a role in disease pathogenesis.     

Mechanisms Involved in the Anti-Inflammatory Action of a Polysulfated Fraction from Gracilaria cornea in Rats

The anti-inflammatory mechanisms of the sulfated polysaccharidic fraction obtained from red marine alga Gracilaria cornea (Gc-FI) were investigated using a paw edema model induced in rats by different inflammatory agents (carrageenan, dextran, serotonin, bradykinin, compound 48/80 or L-arginine). Gc-FI at the doses of 3, 9 or 27 mg/kg, subcutaneously - s.c., significantly inhibited rat paw edema induced by carrageenan and dextran, as confirmed by myeloperoxidase and Evans’ blue assessments, respectively. Gc-FI (9 mg/kg, s.c.) inhibited rat paw edema induced by histamine, compound 48/80 and L-arginine. Additionally, Gc-FI (9 mg/kg, s.c.) inhibited Cg-induced edema in animals with intact mast cells but did not inhibit that with degranulated mast cells by compound 48/80, revealing a protective role on mast cell membranes. Gc-FI down-regulated the IL-1β, TNF-α and COX-2 mRNA and protein levels compared with those of the carrageenan group, based on qRT-PCR and immunohistochemistry analyses. After inhibition with ZnPP IX, a specific heme oxygenase-1 (HO-1) inhibitor, the anti-inflammatory effect of Gc-FI was not observed in Cg-induced paw edema, suggesting that the anti-inflammatory effect of Gc-FI is, in part, dependent on the integrity of the HO-1 pathway. Gc-FI can target a combination of multiple points involved in inflammatory phenomena.     

清胰汤对大鼠急性坏死性胰腺炎IL-6,IL-10及肠道通透性影响

目的：探讨清胰汤改善大鼠急性坏死性胰腺炎（acute necrotizing pancreatitis）ANP炎症反应及肠道通透性功能的治疗效果及机制。方法：将72只雄性SD大鼠随机分为3组,其中2组大鼠采用从胰腺被膜下多点缓慢均匀注入3.8%牛黄胆酸钠（0.5ml/100g）建立大鼠急性坏死性胰腺炎模型,再分为急性坏死性胰腺炎常规治疗组（A组）、清胰汤干预治疗组（B组）,其他24只大鼠为假手术组（S组）,每组再随机分为24h、48h、72h组。各组于12h后给于肠内营养,B组肠内营养后给于2次清胰汤2.5ml/100g,A组、S组给于同等剂量生理盐水。各组于建模后24h、48h、72h处死,腹腔动脉取血检测血清淀粉酶浓度、IL-6、IL-10、D-乳酸水平。结果：48h时点B组IL-10水平较A组高（P〈0.05）;72时点B组血清淀粉酶水平较A组低（P〈0.01）,IL-6水平较A组低（P〈0.01）,IL-10水平较A组高（P〈0.01）,D-乳酸水平较A组低（P〈0.01）。结论：清胰汤可以上调IL-10改善大鼠急性胰腺炎炎症反应从而降低肠道通透性。     

清胰汤对大鼠急性坏死性胰腺炎IL-6,IL-10 及肠道通透性影响

目的:探讨清胰汤改善大鼠急性坏死性胰腺炎(acute necrotizing pancreatitis)ANP炎症反应及肠道通透性功能的治疗效果及机制。方法:将72只雄性SD大鼠随机分为3组,其中2组大鼠采用从胰腺被膜下多点缓慢均匀注入3.8%牛黄胆酸钠(0.5ml/100g)建立大鼠急性坏死性胰腺炎模型,再分为急性坏死性胰腺炎常规治疗组(A组)、清胰汤干预治疗组(B组),其他24只大鼠为假手术组(S组),每组再随机分为24h、48h、72h组。各组于12h后给于肠内营养,B组肠内营养后给于2次清胰汤2.5ml/100g,A组、S组给于同等剂量生理盐水。各组于建模后24h、48h、72h处死,腹腔动脉取血检测血清淀粉酶浓度、IL-6、IL-10、D-乳酸水平。结果:48h时点B组IL-10水平较A组高(P<0.05);72时点B组血清淀粉酶水平较A组低(P<0.01),IL-6水平较A组低(P<0.01),IL-10水平较A组高(P<0.01),D-乳酸水平较A组低(P<0.01)。结论:清胰汤可以上调IL-10改善大鼠急性胰腺炎炎症反应从而降低肠道通透性。     

氧化苦参碱对哮喘大鼠肺组织IL-10 表达的影响

目的:观察不同浓度氧化苦参碱(Oxymatrinem,Oxy)对哮喘大鼠肺组织IL~(-1)0表达的影响,并探讨其作用机制。方法:构建哮喘大鼠模型,将40只清洁级健康雌性SD大鼠随机分成5组,每组8只:A:哮喘组(仅卵蛋白(Ovalbumin,OVA)致敏)、B:低浓度组(Oxy 50 mg/kg)、C:中浓度组(Oxy 100 mg/kg)、D:高浓度组(Oxy 150 mg/kg)、E:对照组(生理盐水),末次激发24 h后处死全部大鼠,取大鼠肺脏,HE染色观察肺组织病理改变,采用RT-PCR、Western Blot测定各组肺组织中IL~(-1)0基因及蛋白水平的表达。结果:HE结果显示,哮喘组可见大量炎症细胞浸润,气管平滑肌明显增厚。对照组肺泡壁薄且光滑,未见明显炎性细胞的浸润,不同浓度氧化苦参碱药物干预组其肺组织炎症细胞浸润及气管平滑肌病变程度随着用药浓度的增高呈逐渐减轻趋势。RT-PCR以及Western blot检测IL~(-1)0发现,哮喘组、氧化苦参碱低浓度组、氧化苦参碱中浓度组与对照组相比IL~(-1)0的表达均有所减低(P0.05),而氧化苦参碱高浓度组与对照组比较,IL~(-1)0的表达无统计学意义(P0.05);氧化苦参碱中浓度组、氧化苦参碱高浓度组与哮喘组相比IL~(-1)0的表达均有所增高(P0.05),氧化苦参碱低浓度组与哮喘组相比IL~(-1)0的表达无统计学意义(P0.05)。结论:氧化苦参碱抑制、控制哮喘发作可能与促进肺组织中IL~(-1)0基因、蛋白的表达相关,且促进程度在一定范围内与浓度呈正比。     

Differential Susceptibility of SD and CD Rats to a Novel Rat Theilovirus

Antibodies to rat theilovirus (RTV) have been detected in rats for many years because of their serologic crossreactivity with strains of Theiler murine encephalomyelitis virus (TMEV) of mice. Little information exists regarding this pathogen, yet it is among the most common viruses detected in serologic surveys of rats used in research. In the study reported here, a novel isolate of RTV, designated RTV1, was cultured from the feces of infected rats. The RTV1 genome contained 8094 nucleotides and had approximately 95% identity with another rat theilovirus, NSG910, and 73% identity with TMEV strains. In addition, the genome size of RTV1 was similar to those of TMEV strains but larger than that reported for NSG910. Oral inoculation of Sprague–Dawley (SD) and CD male rats (n = 10 each group) with RTV1 revealed that SD rats were more susceptible than CD rats to RTV1 infection. At 14 d postinoculation, 100% of SD rats shed virus in the feces, and 70% were positive for RTV serum antibodies. By 56 d postinoculation 30% of SD rats continued to have detectable virus in the feces, and 90% had seroconverted. In contrast, in inoculated CD rats RTV was detected only in the feces at 14 d postinoculation, at which time 40% of CD rats were fecal positive. By 56 d postinoculation only 20% of CD rats had detectable RTV serum antibodies. Our data provide additional sequence information regarding a rat-specific Cardiovirus and indicate that SD rats are more susceptible than CD rats to RTV1 infection.Abbreviations: RACE, rapid amplification of cDNA ends; RTV, rat theilovirus; SD, Sprague Dawley; TMEV, Theiler murine encephalomyelitis virusFor decades it has been known that rats used in research can develop antibodies to a Cardiovirus that is antigenically similar to Theiler murine encephalomyelitis virus (TMEV) of mice.^{4,6,10,12,13,20} Recent reports on the prevalence of antibodies in rats to this Cardiovirus vary from approximately 0.6% of sera tested from research rats in North America¹⁰ to 54.4% in a survey of 18 Brazilian research facilities.^3,6,20 Multiple designations have been used to identify the Cardiovirus that infects rats, including Theiler-like virus of rats,¹³ Theiler murine encephalomyelitis virus (TMEV),²⁰ rat enterovirus,¹ rat encephalomyelitis virus,⁷ rat cardiovirus,¹⁵ and recently rat theilovirus.² We have elected to refer to the virus as rat theilovirus (RTV), consistent with 1 of the cited references,² to indicate the relation of the rat virus to TMEV of mice and to identify it as a rat-specific agent.The first report of natural infection of rats with a Cardiovirus was in 1964 with the discovery of MHG virus.¹² The finding resulted from an isolated observation in which a few rats in a large research colony displayed clinical signs indicative of central nervous system deficits, including incoordination, torticollis, circling, and tremors. The MHG virus recovered from infected rats was antigenically crossreactive with TMEV strain GDVII and had physical properties consistent with viruses in the Picornaviridae family. The virus was propagated in cell culture, and neurologic disease was reproduced when virus was inoculated into suckling mice and suckling rats.¹² Subsequent serologic studies using crossneutralization, complement fixation, and hemagglutination inhibition assays further substantiated the antigenic relatedness between MHG virus and multiple strains of TMEV.^4,11 In addition, sera from ‘normal’ rats contained antibodies to the newly identified Theiler-like virus of rats, suggesting widespread infection of the virus in research rat colonies.¹² More recently in Japan, a Theiler-like virus was isolated after intracranial inoculation of newborn Wistar rats with intestinal homogenates from TMEV GDVII-seropositive rats.¹³ Inoculated rats did not develop clinical signs of infection, but virus was cultivated in BHK21 cells from brain homogenates of the 10-d-old Wistar rats inoculated intracranially. Physiochemical properties of the virus, designated NSG910, were consistent with those of the Cardiovirus genus. Sequence analysis also showed that NSG910 was a Cardiovirus in the family Picornaviridae that was related to, but distinct from MHG virus, and strains of TMEV. This report served to further document the existence of a unique Cardiovirus of rats closely related to, but distinct from, TMEV strains.¹³ In a recent report from Brazil, neonatal mice and rats inoculated with intestinal homogenates from rats with antibodies to TMEV strain GDVII developed neurologic signs of flaccid hindlimb paralysis and tremors. In addition, brain homogenates from the affected animals were positive by RT-PCR for cardioviral RNA.²⁰Picornavirus virions are approximately 30 nm in diameter, nonenveloped, with icosahedral symmetry and a single-stranded, positive-sense RNA genome.¹⁹ Encephalomyocarditis virus and Theilovirus are 2 species of Cardiovirus in the Picornaviridae family. Encephalomyocarditis virus species includes mengovirus, Maus Elberfeld virus, and Columbia SK virus.⁷ Strains of Theilovirus species include TMEV, Vilyuisk virus, and RTV.^13,18,22 Most often studied are the TMEV strains, which are classified according to their neurovirulence after intracerebral inoculation. Included are the highly neurovirulent GD VII and FA strains²³ and the less virulent, more persistent DA, BeAn 8386, WW, and TO (Theiler original) strains.^9,17,22 Studies have shown that the virus replicates in the alimentary tract and is shed in the feces of infected mice.^15,19 Mice rarely show clinical disease when infected under natural conditions; however, neurologic manifestations have been reported.^21,24Sentinel animals typically are used to survey rodent colonies for the presence or absence of infectious agents. Outbred stocks are frequently used as sentinels because of their vigor, relatively low cost, and ability to mount a robust humoral immune response to infectious agents.^8,14 Sprague–Dawley (SD) and CD rats are 2 stocks that are commonly used as sentinels for rat colonies. The origins of the SD rat (Rattus norvegicus) date back to the 1920s as a result of mating Wistar stock with a hybrid rat stock of unknown origin. In the 1950s, an SD breeding stock was cesarean derived in an effort to improve microbiologic status. This nucleus of cesarean-derived rats formed the foundation of the CD rat stock.²⁵ Because SD and CD rat stocks have a common ancestry, they frequently are considered to be interchangeable for the purpose of sentinel animals.In the studies reported here, we isolated and propagated a novel strain of Theilovirus, referred to as RTV1, from the feces of infected SD rats. The entire genome of RTV1 was sequenced and compared with those of isolates of TMEV and NSG910, the only other isolate of RTV to be sequenced in its entirety. In addition, we evaluated the susceptibility of SD and CD outbred rats to RTV1 after oral inoculation with the virus.     

IL-10 fails to inhibit the production of IL-18 in response to inflammatory stimuli

IL-10 is an inhibitor of the production of pro-inflammatory cytokines such as IL-12 and IL-1beta, but it is not known whether it can inhibit the production of IL-18. Therefore, a variety of in vivo and in vitro models were used to determine whether IL-10 is an inhibitor of IL-18 production. Infection of IL-10-/- mice with Toxoplasma gondii results in increased levels of IL-12 in the serum and in recall responses compared to wild type (WT) mice. Surprisingly, although infection resulted in increased levels of IL-18 in serum, there were no differences between WT and IL-10-/- mice. Moreover, splenocytes from infected WT and IL-10-/- mice produced similar levels of IL-18 and addition of exogenous IL-10 did not inhibit their production of IL-18. To address whether endogenous IL-18 inhibitors were masking increased IL-18 production in the IL-10-/- mice, expression of IL-18 binding protein was examined using RT-PCR. Although infection leads to increased expression of IL-18BP mRNA, no difference was seen between WT and IL-10-/- mice. In addition, splenocytes from IL-10-/- mice produced elevated levels of nitric oxide (NO) compared to WT mice, and NO has been shown to inhibit activity of interleukin-1 converting enzyme (ICE), which is required for IL-18 production. However, the addition of an inhibitor of NO production did not alter the levels of IL-18 produced. Finally, analysis of the levels of cytokine mRNA of macrophages stimulated with LPS and IFN-gamma revealed that although IL-10 is a potent inhibitor of IL-12 mRNA accumulation, it did not inhibit IL-1beta or IL-18. Together, these data indicate that IL-10 is not an inhibitor of the production of IL-18.     

Effects of a Gut Microbiome Toxin,p-Cresol,on the Susceptibility to Seizures in Rats

Neurophysiology - Several studies have highlighted a high comorbidity between epilepsy and autism. We hypothesized that some similar etiological factors might affect both disorders; among such...     

A Hypomagnetic Field Modulates the Susceptibility of Erythrocytes to tert-Butyl Hydroperoxide in Rats

Biophysics - Abstract—Red blood cells of rats were exposed to the earth’s magnetic field and an attenuated magnetic field in the presence of tert-butyl hydroperoxide to induce oxidative...     

IL-10基因对糖尿病大鼠胰岛β细胞凋亡的保护作用

目的：研究白细胞介素10（IL-10）基因对链脲佐菌素（STZ）诱导的糖尿病大鼠胰腺炎症浸润程度及胰腺组织中Bcl-2及Bax表达的影响。方法：建立链脲佐茵素性糖尿病模型,腺病毒介导的IL-10基因（Ad-mIL-10）腹腔注射。检测大鼠空腹血糖值;免疫组织化学法观察胰腺炎症浸润程度;TUNEL法检测胰岛细胞凋亡;免疫组化方法观察Ad-mIL-10对实验性糖尿病大鼠胰岛凋亡调控基因Bax和Bcl．2表达的影响。结果：Ad-mlL-10腹腔注射糖尿病发病率低,平均血糖水平低,可以降低胰腺炎症浸润程度,减少胰岛细胞凋亡。给予Ad-mlL-10后大鼠Bax基因的表达明显下降,Bcl-2与Bax的比值明显增加。结论：IL-10基因对实验性糖尿病大鼠有降血糖作用,减少胰岛细胞凋亡,与调节Bcl-2与Bax基因的表达有关。     

IL-10 基因对糖尿病大鼠胰岛beta细胞凋亡的保护作用

目的：研究白细胞介素10（IL-10）基因对链脲佐菌素(STZ)诱导的糖尿病大鼠胰腺炎症浸润程度及胰腺组织中Bcl-2 及Bax 表达的影响。方法：建立链脲佐菌素性糖尿病模型,腺病毒介导的IL-10 基因(Ad-mIL-10)腹腔注射。检测大鼠空腹血糖值;免疫组 织化学法观察胰腺炎症浸润程度;TUNEL法检测胰岛细胞凋亡;免疫组化方法观察Ad-mIL-10 对实验性糖尿病大鼠胰岛凋亡调 控基因Bax 和Bcl-2 表达的影响。结果：Ad-mIL-10 腹腔注射糖尿病发病率低,平均血糖水平低,可以降低胰腺炎症浸润程度,减 少胰岛细胞凋亡。给予Ad-mIL-10 后大鼠Bax 基因的表达明显下降, Bcl-2 与Bax 的比值明显增加。结论：IL-10基因对实验性糖 尿病大鼠有降血糖作用,减少胰岛细胞凋亡,与调节Bcl-2 与Bax 基因的表达有关。     

Corticosterone Assimilation by a Voluntary Oral Administration in Palatable Food to Rats

Drug delivery in research on nonhuman animals in the laboratory is still challenging because it is usually invasive and stressful. Stress-free voluntary oral drug administration in water lacks precise control of dose and timing of substance ingestion. Voluntary oral consumption of corticosterone has been previously successfully applied in mice using oat flakes, but protocols for oral corticosterone administration in rats remain unavailable. This study assessed the effectiveness of voluntary oral administration to rats of a palatable piece of bread soaked with corticosterone that can be rapidly prepared and is reliably dose- and timing-controllable. After three familiarization days, all rats ate the bread within 120 seconds of presentation, irrespective of the presence or absence of corticosterone or vehicle. Corticosterone plasma levels remained at basal levels with consumption of vehicle-containing bread, and they were significantly increased with corticosterone-containing bread. Hence, the method enabled corticosterone bodily assimilation while avoiding stress, making it a possible alternative for invasive and stressful procedures. This article includes a methodological refinement that lessens unnecessary discomfort to laboratory animals and is potentially suitable for acute and chronic protocol studies.     

Enhanced Susceptibility to Spontaneous Seizures of Noda Epileptic Rats by Loss of Synaptic Zn2+

Zinc homeostasis in the brain is associated with the etiology and manifestation of epileptic seizures. Adult Noda epileptic rats (NER, >12-week-old) exhibit spontaneously generalized tonic-clonic convulsion about once a day. To pursue the involvement of synaptic Zn²⁺ signal in susceptibility to spontaneous seizures, in the present study, the effect of zinc chelators on epileptogenesis was examined using adult NER. Clioquinol (CQ) and TPEN are lipophilic zinc chelotors, transported into the brain and reduce the levels of synaptic Zn²⁺. The incidence of tonic-clonic convulsion was markedly increased after i.p. injection of CQ (30–100 mg/kg) and TPEN (1 mg/kg). The basal levels of extracellular Zn²⁺ measured by ZnAF-2 were decreased before tonic-clonic convulsion was induced with zinc chelators. The hippocampal electroencephalograms during CQ (30 mg/kg)-induced convulsions were similar to those during sound-induced convulsions in NER reported previously. Exocytosis of hippocampal mossy fibers, which was measured with FM4-64, was significantly increased in hippocampal slices from CQ-injected NER that did not show tonic-clonic convulsion yet. These results indicate that the abnormal excitability of mossy fibers is induced prior to epileptic seizures by injection of zinc chelators into NER. The incidence of tonic-clonic convulsion induced with CQ (30 mg/kg) was significantly reduced by co-injection with aminooxyacetic acid (5–10 mg/kg), an anticonvulsant drug enhancing GABAergic activity, which did not affect locomotor activity. The present paper demonstrates that the abnormal excitability in the brain, especially in mossy fibers, which is potentially associated with the insufficient GABAergic neuron activity, may be a factor to reduce the threshold for epileptogenesis in NER.     

Polymorphisms in the Toll-Like Receptor and the IL-23/IL-17 Pathways Were Associated with Susceptibility to Inflammatory Bowel Disease in a Danish Cohort

Background

The inflammatory bowel diseases (IBD), Crohn’s disease (CD) and ulcerative colitis (UC), result from the combined effects of susceptibility genes and environmental factors. Previous studies have shown that polymorphisms in the Toll-like receptor (TLR), the apoptosis, the IL-23/IL-17 and the interferon gamma (IFNG) pathways are associated with risk of both CD and UC.

Methods

Using a candidate gene approach, 21 functional single nucleotide polymorphisms (SNPs) in 15 genes were assessed in a clinical homogeneous group of severely diseased ethnic Danish patients consisting of 624 patients with CD, 411 patients with UC and 795 controls. The results were analysed using logistic regression.

Results

The polymorphisms TLR5 (rs5744174) and IL12B (rs6887695) were associated with risk of CD, and TLR1 (rs4833095) and IL18 (rs187238) were associated with risk of both CD and UC (p<0.05). After Bonferroni correction for multiple testing, the homozygous variant genotype of TLR1 743 T>C (rs4833095) was associated with increased risk CD (OR: 3.15, 95% CI: 1.59–6.26, p = 0.02) and CD and UC combined (OR: 2.96, 95% CI: 1.64–5.32, p = 0.005).

Conclusion

Our results suggest that genetically determined high activity of TLR1 and TLR5 was associated with increased risk of both CD and UC and CD, respectively. This supports that the host microbial composition or environmental factors in the gut are involved in risk of IBD. Furthermore, genetically determined high activity of the IL-23/IL-17 pathway was associated with increased risk of CD and UC. Overall, our results support that genetically determined high inflammatory response was associated with increased risk of both CD and UC.