Current Issue : April - June Volume : 2013 Issue Number : 2 Articles : 6 Articles
Glaucoma is a heterogeneous group of disorders that progressively lead to blindness due to loss of retinal ganglion cells and damage\r\nto the optic nerve. It is a leading cause of blindness and visual impairment worldwide. Although research in the field of glaucoma is\r\nsubstantial, the pathophysiologic mechanisms causing the disease are not completely understood. A wide variety of animal models\r\nhave been used to study glaucoma. These include monkeys, dogs, cats, rodents, and several other species. Although these models\r\nhave provided valuable information about the disease, there is still no ideal model for studying glaucoma due to its complexity. In\r\nthis paper we present a summary of most of the animal models that have been developed and used for the study of the different\r\ntypes of glaucoma, the strengths and limitations associated with each species use, and some potential criteria to develop a suitable\r\nmodel....
The dysregulation of the serotonergic system has long been recognized as an important factor underlying the pathophysiology of\r\nPTSD. To date, SSRIs have already been established as the firstline pharmacotherapeutic agents for treating acute and chronic PTSD.\r\nHowever, SSRIs largely have several disadvantages which limit their utility. Our previous study has also shown that administration\r\nof the total flavonoids, isolated from the extract of Xiaobuxin-Tang (XBXT, mild mind-easing decoction), comprising four Chinese\r\nmedicines including Haematitum, Flos Inulae, Folium Phyllostachydis Henonis, and Semen Sojae Preparatum, exerted significant\r\nantidepressant-like effect in chronically mildly stressed rats, possibly mediated by serotonergic activation. Since the central\r\nserotonergic dysfunction is an important and well-known cause mediating the pathophysiology of trauma-related symptoms in\r\nPTSD, it is reasonable to predict that flavonoids may exert therapeutic effects on PTSD in animal models. Therefore, the present\r\nstudy aims to examine the effect of flavonoids in alleviating the enhanced anxiety and fear response induced in two PTSD animal\r\nmodels. Ser, an SSRI, was administered as a positive control. Furthermore, the changes of brain monoaminergic neurotransmitters\r\nafter chronic flavonoids administration have also been assessed in SPS-treated rats....
Background: The prevalence of asthma in industrialized countries has been increasing dramatically and asthma is\r\nnow the most common chronic disease of children in the United States. The rapidity of the increase strongly\r\nsuggests that changes in environmental exposures are the likely cause of this epidemic. Further, the early onset of\r\nallergic manifestations suggests that these exposures may act on the prenatal development of the immune system.\r\nWe have focused on the potential effects of bisphenol A (BPA), a chemical pollutant with one of the largest\r\nproductions, on the development of childhood asthma. We have reported that perinatal BPA exposure promotes\r\nthe development of allergic asthma in a mouse model. The current study was designed to identify a critical period\r\nof BPA exposure and to begin elucidating the mechanisms for this susceptibility.\r\nMethods: Female BALB/c mice received 10 micro g/ml BPA in their drinking water from one week before\r\npregnancy until the end of the study. Some of the pups were transferred in the first 48 h of life from their BPAloaded\r\nmother to an unexposed mother, or vice versa. Half of the pups were sensitized with a low dose of the\r\nexperimental allergen ovalbumin (OVA), the rest received PBS as an unsensitized controls. On day 22, the pups\r\nwere challenged by inhalations of ovalbumin or PBS followed by quantification of eosinophils in and\r\nhyperreactivity of their airways, major indicators of experimental asthma in this classical mouse model. Hepatic\r\nexpression of two isoforms of UDP-glucuronosyltransferase (Ugt) was quantified by quantitative RT-PCR at various\r\nages.\r\nResults: Pups exposed to BPA in utero and through breast milk, or in utero only, displayed an asthma phenotype\r\nin response to their ââ?¬Å?suboptimalââ?¬Â allergic sensitization, whereas, pups only exposed to BPA postnatally from breast\r\nmilk, did not. The expression of Ugt2b1, an isoform related to BPA clearance in rats, was not detectable in mouse\r\nfetuses and newborn pups, but increased by day 5 and approached adult levels by day 25.\r\nConclusions: Prenatal exposures that produce environmentally relevant burdens of BPA, followed by postnatal\r\nallergic sensitization and challenges, promote the development of experimental allergic asthma. Delayed\r\nexpression of BPA-metabolizing enzymes may explain, at least in part, the enhanced fetal susceptibility to this\r\ncommon environmental contaminant....
Obesity results from a prolonged imbalance between energy intake and energy expenditure, as depending on basal metabolic rate, heat production, thermogenic effects of the diet and physical activity. Diet-induced obesity (DIO) in rodents can be achieved by different regimens and approaches. Diets providing a high fat intake have been established as a “gold standard” to generate obese rodent models and have proven to initiate pathologies similar to those encountered in humans. However, this dietary treatment is far from being standardized and its relevance has been criticized on the basis of findings in humans that total energy intake rather than fat per se determines body fat accumulation in humans. Hence, varieties of high fat diet regimens have been introduced by providing a choice of several palatable food items of variable composition, appearance and texture in addition to a non-purified diet. Further male rats have been considered in developing all types of obesity models and no rationale has been provided as of this discrimination and negligence of using female rats. Another pitfall in the obesity model development is that of the choice of the strain of the rats used for the study. The basis on which the specific strain is being chosen still remains controversial. This present study aimed at comparing and validating different diet induced obesity models utilizing different high fat diet regimens in different strains and gender. Sprague-Dawley and Wistar male and female rats were offered different high fat diet regimens for 7 weeks to induce obesity. Marketed high fat diet group served as a standard. Evaluation parameters like food intake, calorie intake, water intake, % increase in body weight, plasma total cholesterol, HDL-C, LDL-C, VLDL-C, triglyceride, oral glucose tolerance test and insulin tolerance test were performed to assess the efficacy. Diet specific, strain specific and gender specific variation was observed in case of diet induced obesity models. Marketed diet produced better lipid profile and also produced signs of diabetes and thus can be used for obesity-diabetes studies. Vegetable ghee::coconut oil diet produced higher increase in lipid profile in shorter span of dietary manipulation of 4 week and also gave confirmation of equal amount of fat ingested by the entire group. In-house prepared HFD produced better results at the end of 7 week of dietary manipulation. Strain wise Sprague-Dawley rats produced better results and gender wise males showed greater increase in lipid profile than that of females. The results of the study provide clear evidence that vegetable ghee::coconut oil (3:2) diet serves as a better model of hyperlipidemia/obesity as it requires shorter time of dietary manipulation and economically also is more feasible. Marketed diet produced better results but takes longer time to develop and also causes glucose intolerance and insulin resistance thus can serve as a model of obesity and diabetes. Strain wise and gender wise Sprague-Dawley rats and males respectively served as a better model for obesity. The reason for this can be attributed to the metabolic activity as concluded from the calorie intake values that persists in Sprague-Dawley rats and that in males. Further study is required to derive proper conclusions....
Anti-platelet drugs play an important role in the treatment of patients with thrombotic diseases. The most commonly used anti-platelet drugs, namely, aspirin, ticlopidine, and clopidogrel, are effective in the prevention and treatment of cardiovascular diseases. Platelet activation plays a central role in haemostasis, thrombosis and useful in prevention of thromboembolic artery occlusions associated with cardiovascular diseases. This study was performed to examine the efficacy of ginger-juice in the animal models of thrombosis including mice model of pulmonary thromboembolism, arterio-venous shunt model in rats and coagulation parameters. Simultaneously we also studied the effect of ginger-juice on bleeding time, the most prevalent side effect of existing antiplatelet drugs. Intravenous administration of collagen-epinephrine in mice resulted into hind limb paralysis. Pre-treatment with ginger-juice (10 ml/kg) resulted into 25.56±5% protection against collagen and epinephrine induced pulmonary thromboembolism. At the same time bleeding time was also comparable to the aspirin. Standard compound aspirin also resulted into 28.60±2.5% protection; however bleeding time with aspirin was increased by approx 2 fold. The ex-vivo coagulation studies in mice demonstrated no significant affect among any of the coagulation parameters tested. However, administration of ginger-juice resulted in significant decrease in thrombus weight than in control rats (***p<0.001). Clopidogrel (10 mg/kg) treatment also significantly reduced the thrombus weight in comparison to control group (***p<0.001)....
Understanding the mechanisms underlying the process of regeneration and repair of airway epithelial structures demands close\r\ncharacterization of the associated cellular and molecular events. The choice of an animal model system to study these processes\r\nand the role of lung stem cells is debatable since ideally the chosen animal model should offer a valid comparison with the human\r\nlung. Species differences may include the complex three-dimensional lung structures, cellular composition of the lung airway as\r\nwell as transcriptional control of the molecular events in response to airway epithelium regeneration, and repair following injury.\r\nIn this paper, we discuss issues related to the study of the lung repair and regeneration including the role of putative stem cells in\r\nsmall- and large-animal models. At the end of this paper, the author discuss the potential for using sheep as a model which can\r\nhelp bridge the gap between small-animal model systems and humans....
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