Accelerated Loss of Islet β Cells in Sucrose-Fed Goto-Kakizaki Rats, a Genetic Model of Non-Insulin-Dependent Diabetes Mellitus

The Goto-Kakizaki (GK) rat is a spontaneously diabetic animal model of non-insulin-dependent diabetes mellitus, which is characterized by progressive loss of β cells in the pancreatic islets with fibrosis. In the present study, we examined the effects of sucrose feeding on the islet pathology in this model. Six-week-old GK rats were fed with 30% sucrose for 6 weeks to induce severe hyperglycemia, and their condition was compared with that of nontreated rats. Age-matched normal Wistar rats were also given sucrose for the same periods and used for comparison. The sucrose-treated GK rats showed elevated blood glucose levels on oral glucose tolerance tests at 60 minutes and 120 minutes, representing 123% and 127% of values in untreated GK rats, respectively. At the end of the study, the mean β-cell volume density in GK rats was 50% less than that in untreated Wistar rats. Sucrose feeding further reduced the volume densities of β cells to only 50% of the levels of age-matched GK rats. Apoptotic cells were found in islet β cells only in GK rats fed sucrose (mean 0.067%). There appeared to be more islets that immunohistochemically stained strongly positive with 8-hydroxy-deoxyguanosine as a marker of oxidative damage of DNA in GK rats fed sucrose compared with those not given sucrose. GK rats not fed sucrose showed significantly lower proliferative activity of β cells measured by 5-bromo-2′-deoxyuridine uptake and intensified expression of Bcl-2 immunoreactivities at 6 weeks of age compared with those in age-matched Wistar rats. These two indices were reduced in both GK and Wistar rats with increasing age and were not affected by sucrose feeding in either group. The present study thus indicated that sucrose feeding promoted the apoptosis of β cells in GK rats through increased oxidative stress without altering their proliferative activity.     

Nigella sativa amliorates inflammation and demyelination in the experimental autoimmune encephalomyelitis-induced Wistar rats

Multiple sclerosis (MS) is the major, immune-mediated, demyelinating neurodegenerative disease of the central nervous system (CNS). Experimental autoimmune encephalomyelitis (EAE) is a well-established animal model of MS. The aim of the present study was to investigate the protective and ameliorative effects of N. sativa seeds (2.8 g/kg body weight) in EAE-induced Wistar rats. EAE-induced rats were divided into: 1- EAE-induced rats (“EAE” group). 2- “N. sativa + EAE” group received daily oral administration of N. sativa 2 weeks prior EAE induction until the end of the experiment. 3- “EAE + N. sativa” group received daily oral administration of N. sativa after the appearance of first clinical signs until the end of the experiment. All animals were decapitated at the 28th day post EAE-induction. EAE was investigated using histopathological, immunohistochemical and ultrastructural examinations in addition to determination of some oxidative stress parameters in the cerebellum and medulla. N. sativa suppressed inflammation observed in EAE-induced rats. In addition, N. sativa enhanced remyelination in the cerebellum. Moreover, N. sativa reduced the expression of transforming growth factor beta 1 (TGF β1). N. sativa seeds could provide a promising agent effective in both the protection and treatment of EAE.     

Experimental model of heterotopic ossification in Wistar rats

Heterotopic ossification (HO) is a metaplastic biological process in which there is newly formed bone in soft tissues adjacent to large joints, resulting in joint mobility deficit. In order to determine which treatment techniques are more appropriate for such condition, experimental models of induced heterotopic bone formation have been proposed using heterologous demineralized bone matrix implants and bone morphogenetic protein and other tissues. The objective of the present experimental study was to identify a reliable protocol to induce HO in Wistar rats, based on autologous bone marrow (BM) implantation, comparing 3 different BM volumes and based on literature evidence of this HO induction model in larger laboratory animals. Twelve male Wistar albino rats weighing 350/390 g were used. The animals were anesthetized for blood sampling before HO induction in order to quantify serum alkaline phosphatase (ALP). HO was induced by BM implantation in both quadriceps muscles of these animals, experimental group (EG). Thirty-five days after the induction, another blood sample was collected for ALP determination. The results showed a weight gain in the EG and no significant difference in ALP levels when comparing the periods before and after induction. Qualitative histological analysis confirmed the occurrence of heterotopic ossification in all 12 EG rats. In conclusion, the HO induction model was effective when 0.35 mL autologous BM was applied to the quadriceps of Wistar rats.     

A modified “double-hit” induced acute lung injury model in rats and protective effects of tetramethylpyrazine on the injury via Rho/ROCK pathway

We focused on the production and evaluation of a modified “double-hit” induced acute lung injury (ALI) model, which closely mimics the clinical situation. Further, tetramethylpyrazine (TMP), an alkaloid contained in ligustrazine was evaluated for its potent anti-inflammatory effects in this model. Rats were randomized into 4 groups: G1 (NS control group), G2 (“double-hit” group), G3 (low dosage TMP group) and G4 (high dosage TMP group). The rats in G2, G3 and G4 were intraperitoneally injected with a low dose of LPS followed by intratracheal injection with median dose of LPS to establish the “double-hit” model. The rats in G3, G4 were intraperitoneally injected with low (G3), high (G4) dosage TMP for the protection against ALI. Upon termination of the experiment, TMP attenuated the harmful changes in animal model reaction, breathing frequency, histological examination, lung W/D-weight ratio, BAL fluid PMNs percentage, MPO activity and ROCK2 mRNA expression. We found inhibiting RhoA/ROCK pathway might attribute to TMP-induced protection against ALI.     

Resistance to Neurodegenerative Brain Damage in August and Wistar Rats

In Wistar and August rats characterized by different resistance to acute emotional stress we compared the resistance to neurodegenerative brain damage (model of Alzheimer’s disease) produced by administration of a neurotoxic peptide fragment (25–35) β-amyloid into the brain. August rats were more resistant to acute stress and development of neurodegenerative disorders compared to Wistar rats. This conclusion was derived from studying animal behavior in conditioned passive avoidance task and open-field test that characterize cognitive function of the brain. Administration of β-amyloid modulated the behavior of Wistar rats, which reflected the impairment of memory and orientation and exploratory activity in these animals. These disturbances in Wistar rats were accompanied by activation of lipid peroxidation in the hippocampus.__________Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 139, No. 5, pp. 491–494, May, 2005     

Effect of skilled and unskilled training on nerve regeneration and functional recovery

The most disabling aspect of human peripheral nerve injuries, the majority of which affect the upper limbs, is the loss of skilled hand movements. Activity-induced morphological and electrophysiological remodeling of the neuromuscular junction has been shown to influence nerve repair and functional recovery. In the current study, we determined the effects of two different treatments on the functional and morphological recovery after median and ulnar nerve injury. Adult Wistar male rats weighing 280 to 330 g at the time of surgery (N = 8-10 animals/group) were submitted to nerve crush and 1 week later began a 3-week course of motor rehabilitation involving either “skilled” (reaching for small food pellets) or “unskilled” (walking on a motorized treadmill) training. During this period, functional recovery was monitored weekly using staircase and cylinder tests. Histological and morphometric nerve analyses were used to assess nerve regeneration at the end of treatment. The functional evaluation demonstrated benefits of both tasks, but found no difference between them (P > 0.05). The unskilled training, however, induced a greater degree of nerve regeneration as evidenced by histological measurement (P < 0.05). These data provide evidence that both of the forelimb training tasks used in this study can accelerate functional recovery following brachial plexus injury.     

Studies ofd-penicillamine on strain variability and lymph node cellularity in adjuvant arthritis

Experiments were performed in order to ascertain the action ofd-penicillamine (PA) on adjuvant arthritis (AA) in rats and to develop a quantitative evaluation method for PA-like drugs, using Lewis, SD, and Wistar rats. Rats were inoculated in the tail with 0.6 mg ofMycobacterium butyricum suspended in 0.1 ml of liquid paraffin. PA apparently induced enhancement of arthritis only in Lewis rats with a good reproducibility. The enhancing effect of PA was seen when it was administered during the period from day –7 to day –1, from day 0 to day 6, or from day 14 to day 20. In control group of Lewis and Wistar rats, adjuvant caused a rapid increase in the cell number of lymph nodes just after the inoculation, and also a marked increase in spleen cells coinciding with the development of arthritis. In PA-treated Lewis rats, the cell numbers of lymph nodes and spleen significantly surpassed those of control rats. However, PA induced no difference from control in Wistar rats, which were not sensitive to PA treatment during the course of arthritis. These results indicate that AA in Lewis rats is a good model for evaluating the activities of PA-like drugs and that PA may affect lymphocytes in lymph nodes and spleen and induce severer arthritis in Lewis rats.     

Wistar大鼠带形囊尾蚴的鉴定和重度感染的病理分析

目的鉴定动物实验中Wistar大鼠所感染寄生虫的种属和分析其感染特征。方法解剖检查正常条件下饲养的大鼠肝脏表面的囊泡,取囊中的虫体头节以10%甲醛及KOH溶液处理后光学显微镜下进行寄生虫的形态学鉴定;并对所感染部位的肝组织进行病理学检查。结果大鼠生长状况良好,无明显异常体征,寄生的虫体鉴定为带形囊尾蚴;本次所解剖检查的Wistar大鼠对该虫的感染率高达85.7%,感染部位均为肝脏,感染虫体数目为5～120个不等,可见带形囊尾蚴早期和成熟期两种形态;肝脏病理虫体周围有嗜酸性粒细胞、淋巴细胞和浆细胞浸润,未被虫体占位的肝小叶结构正常,未见肝脏纤维瘤样变。结论 Wistar大鼠在饲养中易反复感染带形囊尾蚴,并能耐受重度感染,作为动物模型,一方面应严防该虫的感染对实验结果的干扰,另一方面可作为一个很好的免疫应答的干预模型应用于其他疾病的研究。     

Experimental model of intervertebral disc degeneration by needle puncture in Wistar rats

Animal models of intervertebral disc degeneration play an important role in clarifying the physiopathological mechanisms and testing novel therapeutic strategies. The objective of the present study is to describe a simple animal model of disc degeneration involving Wistar rats to be used for research studies. Disc degeneration was confirmed and classified by radiography, magnetic resonance and histological evaluation. Adult male Wistar rats were anesthetized and submitted to percutaneous disc puncture with a 20-gauge needle on levels 6-7 and 8-9 of the coccygeal vertebrae. The needle was inserted into the discs guided by fluoroscopy and its tip was positioned crossing the nucleus pulposus up to the contralateral annulus fibrosus, rotated 360° twice, and held for 30 s. To grade the severity of intervertebral disc degeneration, we measured the intervertebral disc height from radiographic images 7 and 30 days after the injury, and the signal intensity T2-weighted magnetic resonance imaging. Histological analysis was performed with hematoxylin-eosin and collagen fiber orientation using picrosirius red staining and polarized light microscopy. Imaging and histological score analyses revealed significant disc degeneration both 7 and 30 days after the lesion, without deaths or systemic complications. Interobserver histological evaluation showed significant agreement. There was a significant positive correlation between histological score and intervertebral disc height 7 and 30 days after the lesion. We conclude that the tail disc puncture method using Wistar rats is a simple, cost-effective and reproducible model for inducing disc degeneration.     

IgA nephropathy in alcohol abuse. An animal model

In search of an animal model for alcohol abuse related IgA nephropathy, we investigated the Tsukamoto-French alcoholic rat. Continuous intoxication was induced by gastric infusion of a liquid diet with up to 47% ethanol in Wistar rats designated "alcoholic". Control animals received the same calorie count in the form of glucose. Animals were sacrificed after 6 or 10 weeks. IgA nephropathy was observed in 67% (10 of 15) of alcoholic rats and in none of 14 controls (p less than 0.0002). Alcohol abuse related renal changes, similar to those described in humans were present. These included mild mesangial expansion and intense IgA deposition. Foot process effacement was observed in alcoholic animals; severe proteinuria was found in half the animals with IgA nephropathy. This is the first report of chronic ethanol ingestion induced mesangial IgA nephropathy in an animal model.     

Iron-free neoplastic nodules and hepatocellular carcinoma without cirrhosis in Wistar rats fed a diet high in iron

Although excess hepatic iron in hereditary haemochromatosis and dietary iron overload in the African causes hepatocellular carcinoma, it usually does so in the presence of cirrhosis. A direct hepatocarcinogenic effect of iron has not been proved. Moreover, an animal model of hepatocellular carcinoma induced by iron overload has not been available. The aim of this study was to develop such a model and to use it to ascertain whether excess hepatic iron is directly hepatocarcinogenic. Sixty Wistar albino rats were fed a chow diet and 60 the same diet supplemented initially with 2% carbonyl iron for 12 months, followed by 0.5% ferrocene for 20 months. Five rats from each group were sacrificed every 4 months for 24 months for histological and biochemical monitoring. By 16 months, hepatocytes in all the rats receiving the iron-supplemented diet showed grade 4 iron overload, comparable in degree with that seen in patients with advanced hereditary haemochromatosis and dietary iron overload. Altered hepatic foci and pre-neoplastic nodules were first seen at 16 months. These increased in size and number with time, were iron-free, stained positively with placental glutathione sulphydryl transferase, and showed the same histological features as the iron-free foci described in patients with hepatocellular carcinoma complicating hereditary haemochromatosis. At 32 months the eight surviving rats in the iron overloaded group were sacrificed. The livers of five of these rats contained pre-neoplastic nodules and one showed, in addition, an iron-free, well-differentiated hepatocellular carcinoma. The tumour stained positively for placental glutathione sulphydryl transferase. Neither cirrhosis nor portal fibrosis was present in this or any iron-loaded animal. We conclude that hepatocellular carcinoma may complicate dietary hepatic iron overload in Wistar albino rats in the absence of fibrosis or cirrhosis, confirming an aetiological association between dietary iron overload and the tumour and suggesting that iron may be directly hepatocarcinogenic.     

Behavioural correlates of striatal glial fibrillary acidic protein in the 3-nitropropionic acid rat model: disturbed walking pattern and spatial orientation

The 3-nitropropionic acid animal model is a model where excitotoxicity, mitochondrial dysfunction and oxidative stress, mechanisms common to various neurodegenerative diseases, are involved. The present study investigated whether behavioural alterations in this model were related to striatal damage. Wistar and Lewis rats were exposed to 3-nitropropionic acid and their behavioural performance (open field, walking pattern and Morris Water Maze task) was tested after the injections and after a recovery period of 3 weeks. No changes in activity were found in the open field test. Altered walking pattern was observed in the footprint analysis, although a different response was observed in the Wistar rats compared to the Lewis rats. Initially increased latency times were observed during visual discrimination learning in the Morris Water Maze task in 3-nitropropionic acid-treated Wistar rats compared to Wistar controls. During spatial discrimination learning (invisible platform) in the Morris Water Maze task the swimming velocity was decreased in both rat strains as a result of 3-nitropropionic acid treatment. Increased striatal glial fibrillary acidic protein concentration in Wistar rats correlated with several parameters of the footprint analysis and with the latency and distance in visual as well as spatial discrimination learning in the Morris Water Maze. It is concluded that measurement of walking pattern and spatial orientation performance are sensitive indicators to monitor behavioural changes in relation to striatal degeneration in the 3-nitropropionic acid animal model. In addition, Lewis rats are less sensitive towards 3-nitropropionic acid treatment than Wistar rats.     

Wistar Kyoto and Wistar rats differ in the affective and locomotor effects of nicotine

Anhedonia is a characteristic of clinical depression and has been associated with dysfunction of the mesolimbic dopaminergic system, a system also involved in mediating nicotine reward. To further examine the relationship between anhedonia, clinical depression and nicotine reward, the present experiment determined if Wistar Kyoto (WKY) rats, an animal model of clinical depression, differed from Wistar rats in nicotine conditioned place preference (CPP). Strain differences in nicotine-induced changes in locomotor activity also were determined simultaneously. To determine if strain differences were specific to reward-based learning, nicotine or lithium chloride (LiCl) conditioned taste avoidance (CTA) experiments were conducted. Rats received vehicle or nicotine (0.4 or 0.8 mg/kg) during a multi-trial, biased CPP training procedure or received vehicle, nicotine (0.2, 0.4 or 0.8 mg/kg) or lithium chloride (LiCl; 0.0375, 0.075 or 0.15 M) during a multi-trial CTA training procedure. Whereas both nicotine doses (0.4 and 0.8 mg/kg) initially induced hypoactivity, only the moderate nicotine dose (0.4 mg/kg) induced hyperactivity with repeated administration and produced a CPP in Wistar rats. Both nicotine doses failed to alter locomotor activity or produce a CPP in WKY rats. WKY rats also acquired a LiCl CTA more slowly and less robustly compared to Wistar rats. In contrast, nicotine dose-dependently produced a CTA in both strains and WKY rats were more sensitive to the avoidance effects of nicotine compared to Wistar rats. Collectively, these results suggest that WKY rats show deficits in nicotine reward and specific aversive drug stimuli compared to Wistar rats.     

Interactive effects of endogenous morphine,nitric oxide,and ethanol on mitochondrial processes

Positive evolutionary pressure has preserved the ability to synthesize chemically authentic morphine, albeit in homeopathic concentrations, throughout animal phyla. The prototype catecholamine dopamine (DA) serves as an essential chemical intermediate in morphine biosynthesis both in plants and animals, thereby providing considerable insight into the roles reciprocal “morphinergic” and catecholamine regulation of diverse physiological processes. Primordial, multi-potential cell types, before the emergence of specialized plant and animal cells/organ systems, required selective mechanisms to limit their responsiveness to environmental noise. Accordingly, cellular systems that emerged with the potential for recruitment of the free radical gas nitric oxide (NO) as a multi-faceted autocrine/paracrine signaling molecule were provided with extremely positive evolutionary advantages. Endogenous “morphinergic” in concert with NO-coupled signaling systems have evolved as autocrine/paracrine regulators of metabolic homeostasis, energy metabolism, mitochondrial respiration and energy production. Basic physiological processes involving “morphinergic”/NO-coupled regulation of cardiovascular mitochondrial function, with special emphasis on the interactive effects of ethanol, are discussed within the context of our review.     

Prostatitis

The laboratory diagnosis of acute bacterial prostatitis is straightforward and easily accomplished in clinical laboratories. Chronic bacterial prostatitis, and especially chronic idiopathic prostatitis (most often referred to as abacterial prostatitis), presents a real challenge to the clinician and clinical microbiologist. Clinically, the diagnosis of chronic idiopathic prostatitis is differentiated from that of acute prostatitis by a lack of prostatic inflammation and no “significant” (controversial) leukocytes or bacteria in the expressed prostatic secretions. Despite these diagnostic criteria, the etiology of chronic idiopathic prostatitis is unknown. While this review covers the entire spectrum of microbially caused acute prostatitis (including common and uncommon bacteria, viruses, fungi, and parasites) and microbially associated chronic prostatitis, a special focus has been given to chronic idiopathic prostatitis. The idiopathic syndrome is commonly diagnosed in men but is poorly treated. Recent data convincingly suggests a possible bacterial etiology for the condition. Provocative molecular studies have been published reporting the presence of 16S rRNA bacterial sequences in prostate biopsy tissue that is negative for ordinary bacteria by routine culture in men with chronic idiopathic prostatitis. Additionally, special culture methods have indicated that difficult-to-culture coryneforms and coagulase-negative staphylococci are present in expressed prostatic secretions found to be negative by routine culture techniques. Treatment failures are not uncommon in chronic prostatitis. Literature reports suggest that antimicrobial treatment failures in chronic idiopathic prostatitis caused by organisms producing extracellular slime might result from the virulent properties of coagulase-negative staphylococci or other bacteria. While it is difficult to definitively extrapolate from animal models, antibiotic pharmokinetic studies with a murine model have suggested that treatment failures in chronic prostatitis are probably a result of the local microenvironment surrounding the persistent focal and well-protected small bacterial biofilms buried within the prostate gland. These conclusions support the molecular and culture data implicating bacteria as a cause of chronic idiopathic prostatitis.     

Autochthonous male urothelial carcinoma immune competent model: from induction to BCG transurethral treatment

Objective: To describe a new animal model of autochthonous urothelial cancer (UC) accessible by transurethral catheter in males, from induction to treatment. Seven-week-old male Fischer 344 rats were used. The first 10 animals were used to overcome and standardize the technical challenges of safe transurethral catheterization of male rats. The remaining 14 animals underwent intravesical N-Methyl-Nitrosourea (MNU) instillation for UC induction, of which six were randomized to undergo intravesical BCG treatment. The stretched male rat urethra travels 35 mm in a tortuous “S” shaped trajectory with a 180° angle behind the pubic bone, safely traversed by a 20G 36” 0.8 mm epidural catheter in a stretched, straightened urethra inserted after anterior dilation of the penile urethra with a 24G IV catheter. Histopathologic analysis of the urinary bladder demonstrated Stage pT1, pTa, and pTis lesions in the 8 controls, all with increased cell proliferation by Ki-67 expression and no pT1 or pTis in the animals 6 treated with BCG. This pioneering study describes an autochthonous, effective, and accessible transurethral animal model of immune-competent UC in males, and may help with understanding of the biology, immunology, and treatment of UC, which predominates in males.     

血管活性肠肽抑制实验性类风湿性关节炎的研究

类风湿性关节炎是一种自身抗原未明的慢性自身免疫病,以多关节的慢性炎症及渐进性骨和软骨的破坏为主要特征。胶原诱导的关节炎因其临床表现、病理组织学改变以及免疫学表现等方面与类风湿性关节炎的相似性而成为理想的动物模型。在成功建立了胶原诱导的大鼠关节炎模型(CIA)的基础上采用了血管活性肠肽(VIP)注射,研究其干预关节炎发生的效果。结果显示:使用血管活性肠肽组的大鼠CIA发病率和严重程度明显降低,关节肿胀以及骨和软骨的破坏减轻,大鼠血清中抗胶原抗体水平显著降低,大鼠T淋巴细胞对胶原的增殖反应也显著降低。提示VIP可能通过减轻对胶原的免疫应答而抑制关节炎症状,具有可能的临床应用价值。     

Two different putative genetic animal models of childhood depression—A review

Estimated prevalence of childhood and adolescent depression varies from 0.4% to 3% at the 0–12 age range and 3.3% to 12.4% at the 13–18 age range. Despite similarities in the clinical picture of major depression in children, adolescents, and adults, there are notable differences in the neurobiological correlates and treatment response of depressed patients in these different age cohorts. In contrast to adults, most depressed children fail to respond to antidepressants. The main aim of this paper is to review several studies which attempt to develop and examine genetic animal models for childhood depression, in order to enable a search for new, unique treatment approaches for depressed children. Two different “depressive-like” rat strains were studied: Flinders Sensitive Line (FSL) and their controls, Sprague–Dawley (SD) rats; and the Wistar Kyoto (WKY) strain and their controls, Wistar rats. The results suggest that prepubertal FSL and WKY rats exhibit different styles of depressive behavior, one co-morbid with “anxiety-like” behavior (WKY), and one that is not (FSL). These two profiles may model clinical characteristics that resemble two subgroups of depressed children. However, in general the data on the WKY rats would seem most consistent with a classic childhood depressive profile. The FSL profile may possibly be related to chronic stress, and its role as a potential model of childhood depression requires further support. These two different putative genetic animal models of childhood depression can help in the attempts to understand the neurobiological basis and to predict successful treatment strategies for different patterns of childhood psychopathology.     

Differences in bitter taste perception in three strains of rats

Micromolar concentrations of cycloheximide (CH) can be used to test for genetic differences in the ability to taste bitter substances. Three related strains of rats — Fawn-hooded, Long Evans, and Wistar — differ significantly in their ability to taste this substance, the former being unusually deficient in this respect. Wistar and Long Evans rats are able to perceive millimolar concentrations of phenylthiocarbamide (PTC) and 0.2 M CH. FH animals are unable to detect millimolar PTC and first recognize CH when it is present in 1.5 M concentration.     

Experimental animal models for rheumatoid arthritis

Rheumatoid Arthritis (RA) is an autoimmune systemic disorder of unknown etiology and is characterized by chronic inflammation and synovial infiltration of immune cells. RA is associated with decreased life expectancy and quality of life. The research on RA is greatly simplified by animal models that help us to investigate the complex system involving inflammation, immunological tolerance and autoimmunity. The animal models of RA with a proven track record of predictability for efficacy in humans include: collagen type II induced arthritis in rats as well as mice, adjuvant induced arthritis in rats and antigen induced arthritis in several species. The development of novel treatments for RA requires the interplay between clinical observations and studies in animal models. However, each model features a different mechanism driving the disease expression; the benefits of each should be evaluated carefully in making the appropriate choice for the scientific problem to be investigated. In this review article, we focus on animal models of arthritis induced in various species along with the genetic models. The review also discussed the similarity and dissimilarities with respect to human RA.