Spraque-Dawley Rats Research Articles

261 ELUCIDATING MECHANISMS FOR RISK OF URINARY TRACT INFECTION WITH NEUROGENIC BLADDER

You have accessJournal of UrologyPediatrics: Basic Research1 Apr 2011261 ELUCIDATING MECHANISMS FOR RISK OF URINARY TRACT INFECTION WITH NEUROGENIC BLADDER Zarine Balsara, Patrick Seed, and Sherry Ross Zarine BalsaraZarine Balsara Durham, NC More articles by this author , Patrick SeedPatrick Seed Durham, NC More articles by this author , and Sherry RossSherry Ross Durham, NC More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2011.02.352AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Neurogenic bladder (NB) poses an increased risk for urinary tract infections (UTI) and progressive renal damage. Currently, there are no successful strategies to reduce incidence of recurrent UTI (rUTI). With the aim of developing new therapeutics, we report the development of a model of experimental E. coli UTI in spinal cord injured (SCI) rats. We hypothesized that SCI rats would require lower inocula of E. coli to establish infection, have an exaggerated inflammatory response, and have delayed clearance of infection compared to normally voiding rats. METHODS Following a 2-week recovery period from T10 spinal cord transection or sham surgery, female Spraque-Dawley rats were transurethrally inoculated with 107–108 colony forming units (CFU) of the prototypic E. coli cystitis strain, UTI89. At 24h post-infection (hpi), urine, bladders, and kidneys were harvested and plated to enumerate CFU. Histopathology was performed to score inflammation. RESULTS T10 transection resulted in a NB phenotype with elevated residual urine volumes that stabilized at 2.4ml (range = 0.5ml-6.0ml) at 2 weeks post-injury. An inoculum of 107 CFU produced infection in 82% of SCI animals. SCI and control rats had statistically equivalent CFU in all samples (Table 1) and similar inflammatory infiltrates, predominated by neutrophils. Intracellular bacterial communities (IBC), which are collections of bacteria that serve as intracellular foci for rapid bacterial replication protected from the host inflammatory response and antibiotics, were also found in the bladder epithelium of both groups. This demonstrates that the SCI epithelium retains competence for intracellular replication by E. coli. Table 1:. Recovery of E. coli UTI89 from genito-urinary organs of SCI and control rats at 24hpi SCI rats Control rats CFU/ml-organ(GeometricMean) 95%CI(Lower,Upper) CFU/ml-organ(GeometricMean) 95%CI(Lower,Upper) p-value(Mann-Whitney) Urine 1.08×106 3.18×104,3.67×107 1.04×106 2.00×102,2.80×1010 0.9479 Bladder 6.38×105 9.42×103,4.32×107 9.73×105 2.00×102,1.42×1010 0.9480 RightKidney 9.18×104 3.07×103,2.75×106 5.88×104 2.00×102,3.24×108 1.0000 LeftKidney 9.38×103 6.55×102,1.34×105 5.49×104 2.00×102,3.96×108 0.4727 CONCLUSIONS These data suggest that SCI and control rats have similar susceptibility to initiating UTI with E. coli. Other mechanisms, such as differences in clearance or establishment of persistent intracellular bacterial reservoirs, may account for higher rates of rUTI in patients with NB. Ongoing studies will address differences in clearance of infection and differential inflammatory responses between SCI and control rats. These studies will elucidate underlying mechanisms for increased rates of rUTI in NB and lay the groundwork for new antibiotic-sparing preventative therapies. © 2011 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 185Issue 4SApril 2011Page: e105 Peer Review Report Advertisement Copyright & Permissions© 2011 by American Urological Association Education and Research, Inc.MetricsAuthor Information Zarine Balsara Durham, NC More articles by this author Patrick Seed Durham, NC More articles by this author Sherry Ross Durham, NC More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Influence of rat substrain and growth conditions on the characteristics of primary cultures of adult rat spinal cord astrocytes

Primary astrocyte cell cultures have become a valuable tool for studies of signaling pathways that regulate astrocyte physiology, reactivity, and function; however, differences in culture preparation affect data reproducibility. The aim of this work was to define optimal conditions for obtaining primary astrocytes from adult rat spinal cord with an expression profile most similar to adult human spinal cord astrocytes. Hence, we examined whether different Sprague–Dawley substrains and culture conditions affect astrocyte culture quality.Medium supplemented with fetal bovine serum from three sources (Sigma, Gibco, Hyclone) or a medium with defined composition (AM medium) was used to culture astrocytes isolated from spinal cords of adult Harlan and Charles River Spraque–Dawley rats. Purity was significantly different between cultures established in media with different sera. No microglia were detected in AM or Hyclone cultures. Gene expression was also affected, with AM cultures expressing the highest level of glutamine synthetase, connexin-43, and glutamate transporter-1.Interestingly, cell response to starvation was substrain dependent. Charles River-derived cultures responded the least, while astrocytes derived from Harlan rats showed a greater decrease in Gfap and glutamine synthetase, suggesting a more quiescent phenotype. Human and Harlan astrocytes cultured in AM media responded similarly to starvation. Taken together, this study shows that rat substrain and growth medium composition affect purity, expression profile and response to starvation of primary astrocytes suggesting that cultures of Harlan rats in AM media have optimal astrocyte characteristics, purity, and similarity to human astrocytes.

Hepatic expression of spermatogenic genes and their transiently remarkable downregulations in Wistar-Kyoto rats in response to lead-nitrate administration: strain-difference in the gene expression patterns

Administration of lead ion (Pb) to rats and mice affects hepatic functions such as the induction of hepatic cell proliferation and upregulation of cholesterol biosynthesis. To identify the genes for which expression changes in response to Pb-administration, we analyzed hepatic gene expression patterns in stroke-prone spontaneously hypertensive rat (SHRSP), its normotensive control, Wistar-Kyoto rat (WKY), and Spraque-Dawley (SD) rat strains, 3, 6, and 12 hr later after single i.v. injection of lead nitrate (LN) at a dose of 100 µmol using a DNA microarray technique. The data analysis demonstrated that the expression of a great number of genes was transiently and remarkably downregulated 3 hr after LN-injection, and then recovered to control levels only in LN-injected WKY. These normal hepatic expression levels in WKY and SHRSP were much higher than those in SD rats. Furthermore, most of these genes were ones thought to be expressed specifically in the spermatids and/or testes; i.e. genes encoding protamin 1, transition protein 1, and transition protein 2. These findings suggest that the regulation system common to expression of all of these genes could be a target site of Pb-toxic action, at least, in the liver of WKY, and that this system might be similar to the system essential for spermatogenesis, especially spermiogenesis, in the testis. In addition, it appears that clarifying the cause of the difference between the systems of WKY and SHRSP might aid in identifying the pathologic genes in SHRSP. Finally, it will be an important to clarify how the products of the genes related to spermatogenesis, including spermiogenesis, are functional in the livers of WKY and SHRSP.

Effects of asiatic acid on passive and active avoidance task in male Spraque–Dawley rats

Centella asiatica has a reputation to restore declining cognitive function in traditional medicine. To date, only a few compounds that show enhancing learning and memory properties are available. Therefore, the present study investigates the effects of for acute administration of asiatic acid (A-A) isolated from Centella asiatica administration on memory and learning in male Spraque-Dawley rats. 4-5 weeks Spraque-Dawley rats were administered with concentration 1, 3, 5, 10, 30 mg/kg of A-A, baclofen, scopolamine and saline intra peritoneally and were evaluated for passive avoidance (PA), active avoidance (AA) and changes in blood pressure (BP). Treatment 30 mg/kg of A-A resulted in significantly dose-dependently improved memory, with increased retention latency to enter difference compartment in PA test compared to baclofen, saline and scopolamine. Furthermore, 30 mg/kg of A-A was significantly higher on learning abilities on 1st day but there was no significantly difference on avoidance memory ability after 7 days of retention. Low reading in blood pressure dose-dependent significantly difference was observed in the 30 mg/kg of A-A group compared to saline group. Administration A-A facilitated PA and AA on memory and learning and but had no effect on active avoidance on memory. Hence, may serve useful memory and learning with less effect in blood pressure in promoting memory and learning increases.

The effectiveness of melittin injection in rats with chronic prostatitis pain

Objective To test the effectiveness of melittin in chronic prostatic pain model. Methods Adult male Spraque-Dawley rats were injected with complete freunds adjuvant (CFA) into the prostate to make chronic prostatic inflammation. Melittin was injected into the prostates of these models 12 days later. The nociceptive effects were evaluated by using a behavior approach ( mechanical threshold measurement) at the 6th, 12th, and 18th day respectively after intraprostatic injection of CFA. The level of cyclooxygenase (COX-2) in prostate and glial fibrillary acidic protein (GFAP) expression in spinal cord were detected by immunohistochemistry. The rats in control group were injected with normal saline. Results CFA induced rats local allodynia, increases in inflammatory cell quantity and COX-2 expression in prostate, and GFAP expression in spinal cord. Melittin injection significantly raised pain mechanical threshold and decreased inflammatory cells quantity, COX-2 and GFAP expression as compared with control group. Conclusion Local injection of melittin can raise pain threshold, inhibit accumulation of inflammatory cells and expression of COX-2 and GFAP, produce some analgesic and anti-inflammatory effects in rat chronic prostate pain model. Key words: Prostatitis; Melittin; Chronic pain; GFAP

The protective effect of EPO on Alzheimer disease rat learning and memory injury and its effect on Bcl-xl protein expression in hippocampal CA1 subregion

Objective To explore the protecting mechanism of erythropoietin (EPO) on learning and memory of Alzheimer disease (AD) rats. Methods The AD model was made by injected into rat hippocampal CA1 subregion with amyloid beta-protein(Aβ). Male Spraque-Dawley rats were as the experimental objects, which were randomly separated into 3 groups including Sham, Saline control and EPO treatment. After Aβ was injected into rats hippocampal CA1 subregion ,saline or EPO was respectively injected into the lateral ventricle of rats,with help of stereotaxic coordinates, upon the designed conditions. Hippocampal CA1 subregion Bcl-xl expression changes were observed 24 hours after the operation, and learning and memory abilities were checked 4 weeks after the operation. Results 24 hours after the operation Bcl-xl expression in the EPO group and the Saline group was less than the Sham control ,while Bcl-xl positive cells( 100.42 ± 12.43/field) in the EPO group were more than in the Saline group( 82.06 ± 19.68/field ) (P ＜ 0. 05 ). 4 weeks after the operation learning ability in the EPO group ( 20.38 ± 5.88 ) was better than Saline group ( 25.50 - 3.25 ) (P ＜ 0. 05 ), and memory ability in the EPO group (4.75 ± 1.75 ) was better than the Saline group(2.88 ± 1.55 )(P ＜ 0.05 ). Conclusion EPO could improve the learning and memory abilities in the model rats,and it could be related with EPO restraining Bcl-xl expression decreasing. Key words: Erythropoietin ; Amyloid beta-protein ; Alzheimer disease ; Bcl-xl ; Learning ; Memory ;

Level of TLR4 in the liver of rats with multiple organ dysfunction syndrome

Objective To determine the level of toll-like receptor 4 (TLR4) in the liver of rats with the multiple organ dysfunction syndrome (MODS), and to investigate the early phase of liver damage in MODS. Method Forty adult male Spraque-Dawley (SD) rats were randomly (random number) divided into two groups, namely the normal control group and the MODS model group. The rats of model group were further divided into 4 sub-groups as per different intervals, 6 h, 12 h,24 h and 48 h, and there were 8 rats in each subgroup. The animal models of MODS were established by two hits in which at first the left eyeball of rat model was removed to bleed to 2 mL/100 g, and four hours later, lipopolysaccharide (LPS, 5 mg/kg) was injected into intraperitoneal cavity of model rats. The same volume of saline instead of LPS was injected intraperitoneally into rats of control group. All rats were sacrificed at different intervals. The histological changes in the liver tissue were observed by naked eye and under light microscope. The levels of TRL4 protein in serum and liver tissue were detected by using flow cy-tometry (FCM). One-way ANOVA was used for comparison among multiple groups. Results (1) There were no histopathological changes in liver of rats in control group, and the liver damage was serious in rats with MODS. (2) Compared withrats of control group, the expression of TLR4 in liver tissue of rats with MODS increased in 6 hours and reached peak 12 hours later (P < 0.01), and then decreased 24 hours after. There was significant difference in level of TLR4 between two groups 48 hours after. Compared with rats of control group, the level of TLR4 in peripheral blood leucocytes of rats with MODS increased significantly 6-48 hours after LPS (P < 0.01).Conclusions The level of TLR4 markedly increases in the liver tissue at early stage of MODS. The TLR4 may play an important role in the pathogenesis of liver injury in MODS, and the TLR4 may become a novel therapeutic target in MODS. Key words: Multiple organ dysfunction syndrome (MODS); Toll-like receptor4 (TLR4); lipopolysacchar-ide(LPS); Systemic inflammatory response syndrome(SIRS); Liver tissue; Two hits; Rat

The role of estrogen receptors, erbB receptors, vascular endothelial growth factor and its receptors, and vascular endothelial growth inhibitor in the development of the rat mammary gland

We identified the localization and distribution of cell-specific epidermal growth factor receptors (EGFRs: erbB-1, erbB-2, erbB-3, erbB-4), vascular endothelial growth factor (VEGF), VEGF receptors [VEGFRs: VEGF-R1 (flt-1), VEGF-R2 (flk-1/KDR), VEGF-R3 (flt-4)], vascular endothelial growth inhibitor (VEGI), and estrogen receptor (ER), and determined whether or not these growth factors in rat mammary glands are functional. Thirty-five adult female Spraque-Dawley rats were randomly divided into five groups, each of which were at the 7th, 14th, and 21st day of pregnancy; 7th day post-delivery; and 7th day after weaning. It was determined that erbB, VEGF and its receptors, VEGI, and ER stained at different intensities. Intense staining was observed, in particular, in erbB receptors during pregnancy and involution, and also in VEGF and its receptors during lactation, while ER stained during the last periods of pregnancy and lactation. In conclusion, the expression of erbB, VEGF and its receptors, and ER were determined at varying intensities at different sites of the mammary gland during pregnancy, lactation, and involution periods.

Combining gastric and ileal segments, does it overcome segment-related complications? An experimental study on rats

Bladder augmentation has revolutionized the care of children with neurogenic bladder but it is associated with certain short- and long-term complications. Using the combination of gastric and ileal segments to balance effects of these segments might be a solution for complications. A total of 39 female Spraque-Dawley rats randomly divided into four groups: ileocystoplasty (11), gastrocystoplasty (9), ileogastrocystoplasty (11) and control (8). Serum/urine electrolytes and pH values, and serum creatinine levels and urine mucus concentration were measured. Kruskal-Wallis non-parametric variance analysis was performed to compare the groups and p < 0.05 was accepted as significant. Metabolic alkalosis with significantly lower urine pH was observed in gastrocystoplasty group. Gastroileal group showed similar results with the ileal group in all parameters. No stone formation was detected in the sham and gastric cystoplasty groups. Metaplastic and hyperplastic changes were observed in all segments surrounding urothelium. In conclusion, combination of gastric and ileal segments does not significantly reduce the rate of metabolic impairments, stone and mucus formation. Besides it is not associated with significant improvement in histological outcome since urine is still in contact with the gastrointestinal mucosa.

Hyperbaric oxygen preconditioning attenuates brain edema induced by infra-cerebral hemorrhage in the experimental rate

Objective To investigate the effects of hyperbaric oxygen preconditioning (HBOP) on brain edema, inflammatory reaction and neuronal cell apoptosis induced by experimental hemorrhage in rats. Method Eighteen male Spraque-Dawley rats, weighing 300 - 350 g,received five successive sessions of HBOP with 3 atmosphere absolute pressure and 100% O2 one hour daily for five successive days, and other eighteen rats received five successive sessions of pretreatment with one atmosphere absolute pressure, air, one hour daily for five successive days. Twenty-four hours after the final pre-conditioning, rats received an infusion of 100 μL autologous blood into the basal ganglion. Seventy-two hours later, rats were sacrificed for brain edema measurements in 12 rats of each group. The histopathological changes around the hematoma were observed microscopically, and the neuronal cell apoptosis was detected by using the terminal deoxynucleotidyl transferase-mediated nick end labeling (TUNEL) in six rats of each group. Data of brain water content were analyzed by using Stata 7.0 software and statistical analysis was carried out by two-tailed Student t -test. Results Compared with the control group, HBOP significantly attenuated brain edema 72 hours after intra-cerebral hemorrhage in experimental rats (81. 6± 0. 7% vs. 82. 8± 0.9%, P < 0.01). Inflammatory cell infiltration and neuronal cell apoptosis were also significantly decreased in the HBOP group. Conclusions HBOP protects the rats against brain edema formation, and quells inflammatory reaction and neuronal cell apoptosis following intra-cerebral hemorrhage in experimental rats. Key words: Hyperbaric oxygen; Preconditioning; Rat; Intracerebral hemorrhage; Brain edema; Inflammatory reaction; Apoptosis; Animal model

The role of sialoadenectomy and epýdermal growth factor (EGF) in skin development

In this study, the effect of epidermal growth factor (EGF) on skin development was investigated. A total of 24 adult female Spraque-Dawley rats were used in the study. The rats were divided into 3 equal groups as control, sialoadenectomy (SX) and sialoadenectomy+epidermal growth factor (SX+EGF). Sialoadenectomy was performed on the other groups except control. After a 21-day recovery period, subjects were made to mate. SX+EGF group rats were also given 12.5 ig/day EGF for each animal orally in the 16, 17th, 18th and 19th days of pregnancy. After pregnancy, the offsprings obtained were grown until the 28th day. All 28-day-old offsprings in all groups were weighed and sacrificed. Skin samples from interscapular region were examined under light and electron microscope. In light and electron microscopy, skin sections of SX group, atrophy in epiderm, hyperkeratosis, decrease in hair follicles and sebaceous glands, along with local thinning of basal membrane, hemidesmosome loss and necrotic cells were seen. In skin sections of SX+EGF group, the view was similar to controls. As a result, epidermal growth factor was concluded to have an important role in skin development.

MicroRNA-34a induces endothelial progenitor cell senescence and impedes its angiogenesis via suppressing silent information regulator 1

Endothelial progenitor cells (EPCs) play an important role in angiogenesis, which is essential for numerous physiological processes as well as tumor growth. Several microRNAs (miRNAs) have been reported to be involved in angiogenesis. MiR-34a, recently reported as a tumor suppressor, has been found to target silent information regulator 1 (Sirt1), leading to cell cycle arrest or apoptosis. However, the role of miR-34a in EPC-mediated angiogenesis was unknown. The present study tested the hypothesis that miR-34a inhibits EPC-mediated angiogenesis by inducing senescence via suppressing Sirt1. Bone marrow-derived EPCs from adult male Sprague-Dawley rats were used. Results of flow cytometry showed that EPCs after 7 days of culture expressed both stem cell markers CD34 and CD133 and endothelial cell markers VEGFR-2 (flk-1) and VE-cadherin. MiR-34a was expressed in normal EPCs, and overexpression of miR-34a via its mimic transfection significantly increased its expression and impaired in vitro EPC angiogenesis. MiR-34a overexpression led to a significantly increased EPC senescence, paralleled with an approximately 40% Sirt1 reduction. Furthermore, knockdown of Sirt1 by its siRNA resulted in diminished EPC angiogenesis and increased senescence. Finally, overexpression of miR-34a increased the level of Sirt1 effector-acetylated forkhead box O transcription factors 1 (FoxO1), an effect mimicked in EPCs following Sirt1 knockdown. In conclusion, miR-34a impairs EPC-mediated angiogenesis by induction of senescence via inhibiting Sirt1.

Effect of corticosteroid dose and duration of administration on colonic anastomosis

Surgical intervention under concomitant steroid therapy can be complicated by impaired anastomotic healing. The aim of this experimental study was to investigate the effects of a corticosteroid (methylprednisolone) on healing colonic anastomoses in relation to the dose and duration of administration. Fifty male Spraque-Dawley rats weighing 200-220 g were divided into five groups each containing 10 rats. No treatment was given in the control group. Group HDST: high-dose methylprednisolone (1 mg/kg/day, intramuscular) treatment for a short term of 2 days; group HDLT: high-dose methylprednisolone treatment for a long term of 60 days; group LDST: low-dose methylprednisolone (0.28 mg/kg/day) treatment for a short term of 2 days; and group LDLT: low-dose methylprednisolone treatment for a long term of 60 days. Standard left colonic anastomosis was performed in all rats. Anastomotic bursting pressure, hydroxyproline measurement, and histopathological data were evaluated in all groups on postoperative day 4. The mean anastomotic bursting pressure value was significantly lower in the HDLT group (P < 0.05). The mean hydroxyproline levels were significantly lower in all groups (P < 0.05). Histopathological results demonstrated significant changes according to neutrophil infiltration, granulation tissue formation, presence of vascularization, and peritonitis in the HDLT, LDST, and LDLT groups (P < 0.05). High and low doses of the corticosteroid produced adverse effects on the healing of colon anastomosis in rats regardless of whether it was administered over a long or short preoperative period. However, the most prominent negative effect was associated with high-dose, long-term corticosteroid administration.

Protective effect of N-acetylcysteine on the intestinal barrier dysfunction after radiation injury in rats

To evaluate the protective effect of N-acetylcysteine (NAC) on the intestinal barrier dysfunction in rats after extensive abdominal radiation with X ray. Twenty-four Spraque-Dawley male rats were divided into normal control group (n=8), radiation group (n=8), and radiation+NAC group (300 mg/kg) (n=8). Radiation injury was induced by X ray with a single dose of 10 Gy. NAC was administered from 4 days before irradiation to 3 days after radiation. Three days after radiation, all the rats were euthanized. The terminal ileum was collected for crypt survival assay and ileal villi count. The tissue samples from mesenteric lymph nodes (MLN), spleen, and liver were harvested under sterile conditions for microbiological analysis and ileum samples were harvested for biochemical analysis. The blood levels of D-lactate, endotoxin and diamine oxidase (DAO) and the ileum samples levels of nitric oxide(NO) were also measured. Rats in radiation+NAC group had a higher survival rate of intestinal crypt [(76.84+/-4.82)% vs (49.64+/-5.48)%, P<0.01], higher intestinal villus count [(8.56+/-0.68)/mm vs (4.02+/-0.54)/mm, P<0.01], lower NO concentration [(0.48+/-0.12) mumol/g vs (0.88+/-0.16) mumol/g, P<0.01], lower levels of D-lactate, endotoxin and DAO (P<0.05 or P<0.01), and significantly decreased enteric bacteria cultured from mesenteric lymph nodes and other tissues as compared with the radiation group (P<0.05 or P<0.01). NAC protects the small intestine from radiation-induced injury maybe through the inhibition of NO in rats.

Increased nitric oxide level in diabetic rats from vitamin C supplementation: an in vivo detection using diaminofluorescein

Background: Vitamin C is of clinical benefit for improvement of impaired endothelial functions in diabetes, but its direct effect on nitric oxide (NO) available in endothelial cells during diabetes as yet remains unclear. Objective: To examine the correlation between level of bioavailable NO and arteriolar vasodilation under the direct effect of vitamin C, using a novel NO-sensitive fluorescent indicator in diabetic rats. Methods: Male Spraque-Dawley rats (200-250g body weight) were used for the experiment. The rats were divided into control (CON) and diabetic rats (DM). The diabetes was induced in rats by injection of streptozotocin (STZ) (50 mg/kg body weight). The direct effects of vitamin C administration on NO bioavailability were examined using a buffer solution containing 4,5-diaminofluorescein-diacetate (DAF-2DA) and acetylcholine (Ach) with or without vitamin C in Krebs-Ringer solution. Twenty minutes after the buffer solution was superfused on the rat mesentery, the changes in DAF-2T fluorescence intensities were examined along the arteriolar walls. By visualizing the microcirculation using FITC-dextran, Ach-induced vasodilation of the arterioles (15 to 35 μm in diameter) was measured using Image Pro-Plus Software. The analysis was made after pre-constriction with norepinephrine, and after topical application of vitamin C (ascorbic acid) on the mesentery and following topical application of Ach. Results: DAF-2DF was a NO-sensitive fluorescent indicator that did not make the microvascular walls visible without endothelial activation by Ach. The administration of vitamin C increased Ach-evoked vasodilation in CON and DM groups. Twenty minutes after vitamin C administration, the DAF-2T fluorescence intensities increased significantly in both groups. Conclusion: Vitamin C improved diabetes-induced endothelial dysfunction by enhancing NO bioavailability. The level of bioavailable NO and endothelium-dependent vasodilation were highly correlated.

Leukocyte-endothelial cell interaction is attenuated by low-intensity exercise training and vitamin C supplementation in diabetic rats

Objective: To determine the effects of vitamin C supplementation and low-intensity exercise training on diabetesinduced endothelial dysfunction. Methods: Male Spraque-Dawley rats were randomly divided into five groups: control (Con), diabetes (DM) (streptozotocin; 50 mg/kg BW, i.v.), diabetes with supplemented vitamin C (DM+Vit.C; 1 g/L mixed in drinking water), diabetes with low-intensity exercise-trained (DM+Ex; running 5 times/week with 13-15 m/min velocity for 30 minutes) and diabetes with supplemented vitamin C and exercisetrained (DM+Vit.C+Ex) groups. The number of leukocyte-endothelial cell (EC) interactions in mesenteric postcapillary venules was monitored using intravital fluorescence videomicroscopy. Liver malondialdehyde (MDA) level, an indicator for oxidative stress, was determined by using the thiobarbituric acid reaction. Results: At 24 weeks, the plasma vitamin C level was significantly increased (p<0.05) in DM+Vit.C and DM+Vit.C+Ex rats when compared with DM rats. DM+Ex and DM+Vit.C+Ex rats had lower triglyceride levels and heart weights when compared with DM rats (P<0.05). Mean arterial pressures were significantly decreased in all treatment groups. DM rats had significantly higher malondialdehyde (MDA) levels and lower activities of superoxide dismutase (SOD) than Con. The number of adherent leukocytes and levels of MDA were significantly lower in DM+Vit.C, DM+Ex and DM+Vit.C+Ex than those of DM rats. Conclusion: The increased leukocyte-EC adherence in diabetic rats is significantly related to increased ROS, based on lower MDA levels. Vitamin C supplementation and regular low-intensity exercise training can prevent these deleterious effects, including hypertension, cardiac hypertrophy, hypertriglyceridemia, and leukocyte-EC adherence. Vitamin C supplementation combined with low-intensity exercise training is highly effective in preventing diabetic cardiovascular complications. Keywords: Diabetic rat, endothelial dysfunction, exercise training, leukocyte, vitamin C.

Effects of Paeoniae Radix Rubra on CRF, c-Fos and TH in the Forced Swimming Test

ABSTRACT Objectives : For the purpose of verifying the anti-depressant effect of Paeo niae Radix Rubra(PR), the expression of corticotropin-releasing factor(CRF), c-Fos and tyrosine hydroxylase(TH) was evaluated after performing the Forced Swimming Test(FST). Methods : Spraque-Dawley rats were ingested PR extract(100mg/kg, 400mg/kg, p.o.) for 3 times prior to FST. And the expression of corticotropin-releasing factor(CRF), c-Fos in the paraventricular nucleus(PVN) and tyrosine hydroxylase(TH) in the locus coelureus(LC) and ventral tegmental area(VTA) was measured immunohistochemically after FST. Results : The duration of immobility was significantly decreased in PR 100mg/kg Group and PR 400mg/kg Group, in comparison with the control group (p<0.001). The expr ession of CRF in the PVN was significantly decreased in PR 400mg/kg Group in comparison of the control gro up (p<0.05). The expression of c-Fos in the PVN was rather significantly increased in PR 100mg/kg Group in comparison with the control group, while almost no change was demonstrated in PR 400mg/kg Group. The ex pression of TH was significantly decreased in VTA in comparison with the control group (p<0.05), but the number of expression cells in LC was slightly decreased in case of PR 100mg/kg group while it was increased in case of PR 400mg/kg Group.Conclusion : Judging from the result of the aforementioned tests, Paeoniae Radix Rubra has decreased immobility. In addition, it has also decreased the expression o f CRF and the expression of TH in VTA, while the expression of c-Fos and of TH in LC has no significance. Theref ore, it is believed that Paeoniae Radix Rubra has an anti-depressant effect by decreased immobility through t he reduced expression of CRF and TH in VTA.Key words : Paeoniae Radix Rubra, FST, CRF, c-Fos, TH, anti-depression

Examination of Long Term Magnetic Fields on Rat Calvarial and Mandibular Bone Mass

ABSTRACTBy means of long term extremely low frequency magnetic field (ELF), this study examined the effect of long term magnethic field on rat calvarian and mandibular bone mass.Fourty five female Spraque-Dawley rats were selected for the study. The rats were divided into 3 groups (n=15); ELF MF with 50Hz, 1.5mT was applied for 6 months, 4 hours/day. Total cranial and mandibular bone mineral density (BMD) and bone mineral content (BMC) of rats were determined by dual-energy X-ray absorptiometry (DXA; Discovery QDR series, Discovery A, Hologic, Inc.). Measurements were recorded for all groups before and after the applications, all data were collected and analyzed statistically.The variations in Group 1, before and after the ELF MF applications with respect to BMC and BMD were considered significant (p<.01, p<.001). The variations in Group 2, that has bone loss with respect to BMC and BMD were considered not significant (p>0.05). The variations in control group, Group 3, with respect to BMC and BMD were considered significant (p<0.05).

Cold exposure and adipose nitric oxide and mast cells: influence on aorta contractility

Both nitric oxide (NO) and mast cells play important roles in adipose and vascular tissue biology. Chronic cold stress decreases the sensitivity of vascular smooth muscle to various contractile agents including norepinephrine (NE). In our previous cold exposure study we found that the contractile response of isolated rat aortas to NE was significantly reduced, and the number of rat aortic adventitial mast cells decreased. Histologically and functionally, white and brown adipose tissue (WAT and BAT) can be distinguished. Beyond its significance in energy store/release and heat production, adipose tissue secretes multiple signaling molecules that have endocrine and paracrine role in the regulation of vascular functions. The aims of the present study were to examine chronic cold exposure-induced alterations in (i) the concentration of NO released from selected regions of WAT and BAT in female and male rats, (ii) the histochemistry of white and brown adipose mast cells, and (iii) whether adipose-derived NO affects the contraction of isolated rat aorta to NE. Twelve females and 12 males Spraque-Dawley rats (150-200 g body weight) were used. The rats were exposed to a cold/freely moving stress for 2 hours each day for 5 consecutive days. At the end of cold exposure, the rats were sacrificed, and samples of thoracic aorta with associated periadventitial adipose tissue (tunica adiposa) were obtained. WAT and BAT were isolated from subcutaneous abdominal and interscapular areas, respectively. The concentration of NO was measured by capillary electrophoresis and mast cells were evaluated histochemically. The response of aorta smooth muscles to NE was recorded in the isolated organ bath. To determine whether adipose-derived NO affects aorta contraction to NE, cumulative dose response curves to NE (10 -8 -10 -3 M) were obtained with or without isolated WAT/BAT suspended in the organ bath medium. In control animals, a gender-related significant difference in NO production in both WAT and BAT was found, NO levels being significantly higher in female than male rats. Data from the contractile response of isolated aorta to NE suggest that receptor affinity to NE is significantly different between female and male controls. Presence of BAT and WAT (isolated from cold-exposure animals) in the bath changed the response of aorta smooth muscle to NE. Displaying a gender dimorphism, BAT/WAT-derived NO, or other vasorelaxing factors, seem to reduce receptor density and/or affinity to NE. Adipose mast cell histochemistry also showed diversity in respect to subtype, gender, and cold exposure. Altogether, we found (i) a gender difference in adipose-released NO and in adipose mast cell histochemistry to cold exposure, and (ii) peripheral adipose tissues affect aortic contractile responses to NE likely by a NO-mediated pathway during cold exposure, suggesting that adipose tissue may limit cold-induced excessive vasoconstriction. Our ongoing study aims at the evaluation of whether aortic tunica adiposa itself could also contribute to this phenomenon. Adipobiology 2009; 1: 67-75.

Hyaluronic acid inhibits the glial scar formation after brain damage with tissue loss in rats

Background Brain tissue scarring (gliosis) was believed to be the major cause of epileptic focus after brain injury, and prevention of scarring could reduce the incidence of seizure. We tried the HA coating onto the cortical brain defect of Spraque-Dawley rats to reduce the marginal glial scarring. Methods A 4 × 2 × 2 mm 3 cortical defect was created in the brain of Spraque-Dawley rats. Three percent HA gel was coated onto the lesion for the experimental groups and normal saline solutions for the control groups. The brain was retrieved 4, 8, and 12 weeks after treatment. The brains were then sectioned and processed for H&E and GFAP staining, and the thickness of the scarring and the number of GFAP+ cells were analyzed. Results The thickness of cutting marginal gliosis was significantly decreased in the HA groups. The 12-week HA group showed the smallest thickness of gliosis, whereas the 12-week control group exhibited the largest thickness of gliosis. The significant difference in the thickness of gliosis was also noted between the HA and the control groups 8 weeks after treatment. The number of GFAP+ cells was also significantly decreased in the HA groups when compared to the respective control group 4, 8, and 12 weeks after the surgery. Conclusion The results support the hypothesis that HA inhibits glial scarring not only by decreasing the thickness of gliosis but also by reducing the number of the glial cells. Furthermore, our results suggest that HA might be used to reduce glial scar formation in central nervous system surgery, which subsequently prevents the post-operation or posttraumatic seizure incidence.