中国树鼩和大鼠大脑皮质功能探索

以中国树鼩和Wistar大鼠为实验对象,用电凝破坏大脑皮质,用Longa、Berderson评分法和游泳的方法进行行为学评定,观察破坏大脑皮质对躯体运动和感觉的影响.结果发现,破坏大脑双侧皮质,动物的躯体运动和感觉均未出现瘫痪和障碍,饮食、活动正常.Longa、Berderson评分法检测,各例动物行为学检测评分均为0分.大鼠游泳耐力实验结果表明,正常对照组、破坏大脑皮质组沉入水下前游泳时间分别为:36.2±0.6min、34.4±0.2 min;沉下次数分别为:13.1±0.3次、11.7±0.4次;游泳总时间分别为:78.1±2.6 min、76.3±1.4 min.以上3项指标与正常对照组比,差异无显著性(P>0.05).实验结果表明,破坏双侧大脑皮质后,动物的躯体运动和感觉均正常.提示,大脑皮质并非是直接控制躯体运动和接受感觉刺激的最高级中枢.     

生姜提取物对阿尔茨海默病大鼠动物模型的氧化应激因子的影响

研究生姜提取物(Ginger Root Extract)对β淀粉样蛋白(β-amyloid protein,Aβ)所致阿尔茨海默病(Alzheirner’s disease,AD)大鼠脑组织氧化应激的影响,进一步探讨生姜提取物对AD的可能治疗作用及其机制。SD健康大鼠60只,雌雄各半,随机分成OP+LG组、OP+MG组、OP+HG组、SHAM组、OP+HupA组和OP组。药物干预4周后,以超氧化物歧化酶(SOD)、过氧化氢酶(CAT)免疫组化染色及丙二醛(MDA)Elisa分析比较大鼠大脑氧化应激指标及病理变化。结果显示OP+HG组、OP+HupA组的SOD、CAT的阳性表达活性明显升高(P<0.05),MDA水平下降显著(P<0.05);在OP+LG组、OP+MG组,干预效果不显著(P>0.05)。生姜提取物在高剂量时对阿尔茨海默病(AD)大鼠具有提高SOD、CAT阳性表达活性及降低MDA水平作用。     

Home ranges of introduced rats on Christmas Island: A pilot study

Understanding the spatial ecology of invasive rats (Rattus spp.) is necessary to inform management actions to reduce their impact on native flora and fauna. This study investigates home range sizes of exotic rats around seabird colonies and urban areas on Christmas Island, where rat predation is suspected to be adversely affecting fledgling success among local seabirds. It was hypothesised that rat home range sizes would be smaller in urban areas owing to more consistent food availability. Home ranges of male rats were significantly larger compared with their female counterparts, with male rats maintaining larger home ranges in urban areas compared with seabird colonies. Conversely, female rats had smaller home ranges in urban areas compared with seabird colonies. Our findings suggest a possible correlation between the spatial distribution of food resources and home range size. Additionally, the spatial distribution of breeding females across the landscape had a significant influence on the home ranges of male rats. These findings have important implications for proposed efforts to manage rat populations on Christmas Island, while also providing valuable information regarding the ecology of invasive rats on tropical islands.     

2,2′-dithienyl diselenide,an organoselenium compound,elicits antioxidant action and inhibits monoamine oxidase activity in vitro

Context: Organoselenium compounds have been described as antioxidant and neuroprotective agents.

Objective: To evaluate the antioxidant action of 2,2′-dithienyl diselenide (DTDS) and its effects in brain monoamine oxidase (MAO) activity in vitro.

Materials and methods: Assays for reactive species (RS), lipid peroxidation, protein oxidation, MAO A and B activities in rat brain homogenate as well as mimetic dehydroascorbate reductase and glutathione S-transferase activities were performed using DTDS (μM range).

Results: DTDS was effective in decreasing the levels of RS as well as lipid peroxidation induced by malonate, sodium nitroprusside or FeCl₂/EDTA and protein carbonyl in the rat brain homogenate. DTDS elicited dehydroascorbate reductase-like and glutathione S-transferase-like activities. DTDS was effective in inhibiting both MAO-A and MAO-B activities.

Discussion: The results demonstrated that DTDS is an antioxidant agent with non-selective inhibitory effect on MAO activity.

Conclusion: DTDS is a promising molecule to be evaluated in experimental models of neurological diseases.     

The Pharmacological effects of novel 5-fluoro-N-(9,10-dihydro-9,10-dioxoanthracen-8-yl)-1H-indole-2-carboxamide derivatives on plasma lipid profile of Triton-WR-1339-induced Wistar rats

A novel series of 5-fluoro-N-(9,10-dihydro-9,10-dioxoanthracen-8-yl)-1H-indole-2-carboxamides (3c–3g) were synthesized. The present study was undertaken to investigate the possible antihyperlipidemic effect of these novel compounds on hyperlipidemic rats. Hyperlipidemia was induced by a single intraperitoneal injection of Triton WR-1339 (300 mg/kg). The tested animals were divided into normal control (NCG), hyperlipidemic control (HCG), compounds 3c-, 3d-, 3e-, 3f-, 3g- and bezafibrate (BF)-treated groups. At a dose of 15 mg/kg, compounds 3c–3g and BF (100 mg/kg) significantly (p < 0.0001) reduced elevated plasma triglycerides levels after 12 and 24 h compared to the hyperlipidemic control group. However, only compounds 3e and 3g obviously showed a significant (p < 0.0001) reduction in plasma total cholesterol levels after 12 and 24 h. Moreover, high-density lipoprotein cholesterol levels were significantly increased in all treated groups. The current study demonstrates that 5-fluoro-N-(9,10-dihydro-9,10-dioxoanthracen-8-yl)-1H-indole-2-carboxamides (3c–3g) have a definite antihyperlipidemic potential and these beneficial activities may contribute to their cardioprotective and antiatherosclerotic role.     

A comparative study on the effect of homobrassinolide and gibberellic acid on lipid peroxidation and antioxidant status in normal and diabetic rats

Dietary content of phytohormones may potentially influence metabolic processes in animal cells. This study therefore aimed to investigate the effect of two plant growth regulators homobrassinolide (HB) and gibberellic acid (GBA) on the antioxidant defense status and lipid peroxidation level in the tissues of normal and streptozotocin- induced diabetic rats. Normal and diabetic rats (Albino –wistar strain) were administered 50μg HB and GBA intradermally each day for seven days and their tissue and blood levels of malondialdehyde (MDA), 4-hydroxy-2-nonenol (4-HNE), reduced glutathione (GSH) content and catalase (CAT) activity were determined. Subchronic treatment of rats with HB reduced lipid perioxidation and elevated antioxidant defense whereas GBA caused enhancement of lipid peroxidation and reduction of antioxidant defense in treated animals compared to the control rats.     

THE INFLUENCE OF MAGNETIC FIELDS ON THE PRIMARY HEALING OF INCISIONAL WOUNDS IN RATS

Our studies were conducted to examine the influence of extremely low frequency magnetic fields (ELF-MF) on skin wound healing in male adults rats. We used 40 Hz and 10 mT sinusoidal fields. We evaluated the rate of wound healing by determining the tissue hydroxyproline concentration and scar imaging in electron microscope. The systemic body response to ELF-MF was detected by analysis of blood morphological and biochemical parameters, such as: RBC, WBC, hemoglobin, hematocrit, reticulocytes, electrolytes, urea, and total protein concentration.

ELF-MF induced the increase of hydroxyproline level in scar tissue and intensified the maternity of collagen seen in the electron microscope. The increase of reticulocyte number in blood confirmed that the healing process in experimental animals was supported by the activation of the oxygen supply and utilization processes, as a result of erythropoietic intensification, without simultaneously upsetting cellular energetic processes. We did not obtain changes in biochemical parameters in blood, such as: electrolytes, urea, and total protein concentration, so we concluded that ELF-MF evoked no negative systemic response.     

Clodronate changes neurobiological effects of pulsed magnetic field on diabetic rats with peripheral neuropathy

Several studies have reported that pulsed magnetic fields (PMFs) can be a choice of therapy for diabetic peripheral neuropathy. However, the exact underlying mechanism of PMF is still not known. The purpose of this study was, therefore, to investigate the effects of clodronate encapsulated with liposome, a specific agent depleting macrophage, on PMF-treated streptozotocin-induced type I diabetic rats with peripheral neuropathy. Effects of PMF, liposome-encapsulated clodronate (LEC) or their combined treatments were investigated in diabetic rats by measuring the thermal latencies, mechanical thresholds, whole blood glucose levels, serum insulin level, and body mass. In diabetic rats, PMF exhibited a decrease in the blood glucose levels but did not change the serum insulin level. Both mechanical thresholds and thermal latencies of diabetic rats enhanced throughout the PMF treatment. During the PMF treatment, the administration of LEC suppressed the PMF-induced decrease in blood glucose level, PMF-induced increase in mechanical threshold and thermal latencies in diabetic animals. In addition, PMF reduced the LEC-induced increase in insulin levels of diabetic rats. Findings demonstrated that although effects of both PMF alone and LEC alone on diabetic animals are mostly positive, LEC may remove the therapeutic efficacies of PMF in combined treatment.     

脑损伤后大鼠NAAG肽酶基因沉默的神经保护

目的：探索沉默NAALADase基因的方法对骨髓间充质干细胞（BMSC）静脉移植,评价其对大鼠脑损伤后的神经保护作用。方法：体外分离培养BMSC,应用小分子干扰RNA转染方法沉默NAALADase基因的表达。建立脑损伤模型后,48h处死动物取脑组织进行Fluom—JadeB组织荧光染色以及HE染色。结果：HE染色显示沉默NAALADase基因BDNF数目明显增多并且损伤后神经元退变也减少。结论：沉默NAAG肽酶的表达后能有效实现对神经的保护作用。     

Acetate supplementation attenuates lipopolysaccharide-induced neuroinflammation

Glyceryl triacetate (GTA), a compound effective at increasing circulating and tissue levels of acetate was used to treat rats subjected to a continual 28 day intra-ventricular infusion of bacterial lipopolysaccharide (LPS). This model produces a neuroinflammatory injury characterized by global neuroglial activation and a decrease in choline acetyltransferase immunoreactivity in the basal forebrain. During the LPS infusion, rats were given a daily treatment of either water or GTA at a dose of 6 g/kg by oral gavage. In parallel experiments, free-CoA and acetyl-CoA levels were measured in microwave fixed brains and flash frozen heart, liver, kidney and muscle following a single oral dose of GTA. We found that a single oral dose of GTA significantly increased plasma acetate levels by 15 min and remained elevated for up to 4 h. At 30 min the acetyl-CoA levels in microwave-fixed brain and flash frozen heart and liver were increased at least 2.2-fold. The concentrations of brain acetyl-CoA was significantly increased between 30 and 45 min following treatment and remained elevated for up to 4 h. The concentration of free-CoA in brain was significantly decreased compared to controls at 240 min. Immunohistochemical and morphological analysis demonstrated that a daily treatment with GTA significantly reduced the percentage of reactive glial fibrillary acidic protein-positive astrocytes and activated CD11b-positive microglia by 40-50% in rats subjected to LPS-induced neuroinflammation. Further, in rats subjected to neuroinflammation, GTA significantly increased the number of choline acetyltransferase (ChAT)-positive cells by 40% in the basal forebrain compared to untreated controls. These data suggest that acetate supplementation increases intermediary short chain acetyl-CoA metabolism and that treatment is potentially anti-inflammatory and neuroprotective with regards to attenuating neuroglial activation and increasing ChAT immunoreactivity in this model.