Effects In Sprague-Dawley Rats Research Articles

Biodistribution and preclinical safety profile of legubicin: A novel conjugate of doxorubicin and a legumain-cleavable peptide linker.

Legubicin is a novel conjugate of doxorubicin and a legumain-cleavable peptide linker. It has been developed to ameliorate the side effects of doxorubicin. Biodistribution in tumor-bearing mice, acute tolerance, and potential systemic toxic effects in Sprague-Dawley rats and beagle dogs of legubicin were assessed. Legubicin exists mainly as a protein complex in plasma after entering the circulation. Compared with conventional doxorubicin at an equal molar dose in mice, we found higher exposure to doxorubicin in tumor (approximately 1.7-fold increase) while lower exposure in normal tissues (an ~3.26-, 3.46-, and 1.29-fold reduction in heart, kidney, and plasma, respectively) in tumor-bearing mice after intravenous injection of legubicin. The acute maximum tolerance dose (MTD) of legubicin was >16 mg/kg doxorubicin equivalent in female rats, 11 mg/kg doxorubicin equivalent in male rats (LD50 of conventional doxorubicin is 10.51 mg/kg), and >8mg/kg doxorubicin equivalent in dogs (MTD of conventional doxorubicin is 1.5mg/kg). Four-week repeat-dose toxicity studies of intravenous legubicin were conducted in rats (5, 10, and 25 mg/kg/dose once weekly) and dogs (3/1.5, 10/5, and 20/10mg/kg/dose once weekly); the dose levels were reduced from the second dose due to intolerable legubicin-associated toxicity at 20 mg/kg. Major organs of toxicity included the gastrointestinal tract, lymphoid and hematopoietic organs, kidney, skin, liver, reproductive organs, and peripheral nerves, which are all associated with doxorubicin. However, cardiotoxicity was only noted at MTD dose levels. Altogether, our results confirm an improved safety profile of legubicin over conventional doxorubicin and support its clinical benefit for treating cancer.

Effects of ursodeoxycholic acid and glutathione combination in spleen TNF-α and apoptotic index in rats with cholestasis

Background: Cholestasis is a disorder of the formation or flow of bile. Among its contributors, tumour necrosis factor (TNF)-α stands out as the most influential inducer of apoptosis. Meanwhile, ursodeoxycholic acid (UDCA) is a valuable agent with choleretic properties, protecting the hepatobiliary system. Glutathione (GSH) enhances endothelial response and prevents liver fibrosisObjectives: This study evaluates the effect of a combination of GSH-UDCA on splenic TNF-α expression and apoptosis index in Sprague Dawley (SD) rats with cholestasisMethods: This experiment with a post-tests-only control group design involving 28 male SD rats. They were randomly into four groups: group (K) with 20 mg UDCA, group 1 (P1) with 10 mg UDCA + 10 mg GSH, group 2 (P2) was given UDCA 20 mg + GSH 15 mg, and group 3 (P3) was given UDCA 30 mg + GSH 20 mg. Cholestasis was obtained by ligation of the common bile duct through a laparotomy. During three weeks of trial, rats were administered daily with UDCA orally and GSH intramuscularly. On day 22, rats were sacrificed and spleen samples were taken for anatomical pathology examination. Results: There were significant differences in TNF-α expression between groups K vs P3; P1 vs P3, and P2 vs P3 (p=0.002). There was a significant difference in the apoptotic index between groups K vs P1 (p<0.001); K vs P2 (p=0.004), and K vs P3 (p=0.005).Conclusions: The UDCA-GSH combination demonstrated a prophylactic effect in SD rats with cholestasis and might be an effective supplemental therapy with UDCA for cholestatic diseases. The difference in TNF-α expression and apoptotic index was lower in SD rats UDCA-glutathione combination group than single dose UDCA. Between TNF-α and the apoptotic index, there is a moderate positive relation.

Safety assessment of phytase transgenic maize 11TPY050 in Sprague-Dawley rats by 90-day feeding study

The present study aimed to evaluate the subchronic toxicity of feeding with phytase-transgenic maize line 11TPY050 in Sprague-Dawley (SD) rats. Rats (n = 10/sex/group) were fed with 12.5%, 25% or 50% (w/w) transgenic maize diet, 12.5%, 25% or 50% (w/w) non-transgenic isoline OSL940 maize diet, or 50% (w/w) commercially available Zhengdan958 maize diet for 90 days. Daily clinical observations and weekly measurements of body weights and food consumption were conducted. Blood samples were collected on day 46 and day 91 for hematology and clinical chemistry evaluations. At the end of the study, macroscopic and microscopic examinations were performed. No effects on body weight and food consumption were observed. The results of hematology, clinical chemistry, and absolute and relative organ weights in the transgenic maize group were comparable to those in the parental maize group. Several statistical differences were not dose-related and were not considered to be biologically significant. Furthermore, the terminal necropsy and histopathological examination showed no treatment-related changes among the groups. The results from the present 90-day feeding study of phytase-transgenic maize 11TPY050 indicated no unexpected adverse effects in SD rats. The phytase transgenic maize 11TPY050 has substantial equivalence with non-transgenic maize.

Subacute toxicological evaluation of AT-533 and AT-533 gel in Sprague-Dawley rats.

As a novel heat shock protein 90 inhibitor, AT-533 exhibits various biological activities in vitro, including anti-viral, anti-tumor and anti-inflammatory activities. Moreover, AT-533 gel, a gel dosage form of AT-533, has been suggested to have anti-keratitis and herpes simplex virus type-1 infection-induced effects on the skin lesions of animals. However, the safety evaluation of AT-533 and AT-533 gel has, to the best of our knowledge, not been examined in in vivo toxicological tests. Therefore, these toxicological tests were carried out in the present study. A 30-day subacute toxicity test for AT-533 was conducted at doses of 1, 2 and 4 mg/kg in Sprague-Dawley rats, while that for AT-533 gel was conducted using a single dose of 5 g/kg. The toxicological tests showed that a high-dose of AT-533 caused lethality and side effects in Sprague-Dawley rats. However, no mortality, loss of appetite and body weight, adverse reactions, or toxicologically relevant alterations in hematology, biochemistry and macroscopic findings (except for skin) occurred in rats exposed to low-dose AT-533 and single-dose AT-533 gel (5 g/kg) during a 30-day subacute dermic toxicity study. The aforementioned results suggested that AT-533 gel is non-toxic for Sprague-Dawley rats, as shown by a dermic subacute toxicity test and that except for slight skin irritation, AT-533 gel had almost no side effects when administered percutaneously for 30 days.

A Novel Acetyl-CoA Carboxylase 2 Selective Inhibitor Improves Whole-Body Insulin Resistance and Hyperglycemia in Diabetic Mice through Target-Dependent Pathways.

Excess intramyocellular lipid (IMCL) deposition in skeletal muscle is closely associated with insulin resistance. Pharmacological inhibition of acetyl-CoA carboxylase (ACC) 2 offers a promising approach to treat insulin resistance through stimulation of mitochondrial fatty acid oxidation (FAO) and reduction of IMCL deposition. Previously reported experimental ACC2 inhibitors exhibited plasma glucose-lowering effects in diabetic rodents. However, their antidiabetic action may be potentially biased by off-target effects on triglyceride metabolism or by neurologic side effects. In this study, we investigated a safety profile, target dependency of its action, and antidiabetic efficacy of compound 2e, a novel olefin derivative potent ACC2 selective inhibitor. Four-day administration of suprapharmacological dose of compound 2e did not exhibit any obvious side effects in Sprague-Dawley rats. In db/db mice, single administration of compound 2e led to significantly elevated FAO and reduced IMCL deposition in skeletal muscle. In ACC2 knockout mice, treatment with pharmacological doses of compound 2e did not reduce plasma triglyceride levels, whereas A-908292, a previously reported ACC2 inhibitor, caused a significant triglyceride reduction, showing that compound 2e was devoid of off-target triglyceride-lowering activity. Chronic treatment of db/db mice with compound 2e improved hyperglycemia but did not decrease plasma triglyceride levels. Additionally, compound 2e showed significant improvements of whole-body insulin resistance in the clamp study and insulin tolerance test. Collectively, compound 2e demonstrated a good safety profile and significant antidiabetic effects through inhibition of ACC2-dependent pathways. These findings provide further evidence that selective inhibition of ACC2 is an attractive strategy against insulin resistance and type 2 diabetes. SIGNIFICANCE STATEMENT: This study shows that pharmacological inhibition of acetyl-CoA carboxylase (ACC) 2 leads to significant improvements in whole-body glucose homeostasis, independently of off-target metabolic pathways and toxicity, which were observed in previously reported ACC2 inhibitors. These findings support the concept that ACC2-selective inhibitors will be a novel remedy for treatment of type 2 diabetes.

Gestational and perinatal exposure to diazinon causes long-lasting neurobehavioral consequences in the rat

Diazinon is a widely-used organophosphate pesticide. Pulsatile exposure to diazinon during neonatal development has previously been shown cause long-term neurobehavioral impairments in rats. However, the effects of chronic low concentration exposures during perinatal development remain unclear. This experiment evaluated such effects in Sprague-Dawley rats by implanting osmotic pumps in breeder females prior to conception (N = 13–15 litters per condition) which then delivered chronic, zero order kinetic low-level infusions of 0, 114 or 228 ug/day of diazinon throughout pregnancy. One male and one female from each litter was assessed with a battery of behavioral tests that continued from four weeks of age into adulthood. Litter was used as the unit of variance for the analysis of variance test of significance, with sex as a within litter factor. Diazinon treatment condition was the between subjects factor and time or sessions were repeated measures. Chronic diazinon exposure from pre-mating until the neonatal period caused a significant (p < 0.05) increase in percent of time spent on the open arms of the elevated plus maze, an index of risk-taking behavior. Gestational and lactational diazinon exposure also caused a significant (p < 0.05) degree of hyperactivity in the Figure-8 apparatus during adolescence, specifically affecting the early part of the hour-long test session. This effect had dissipated by the time the rats reached adulthood. Diazinon exposure also caused a significant impairment in novel object recognition, a test of cognitive function. Offspring exposed to 228 ug/day diazinon (p < 0.05) showed significantly less preference for the novel vs. familiar object than controls during the first five minutes of the novel object recognition test.

Exercise Reduced Cardiac Damage from Doxorubicin-Induced Heart Failure Via Anti-Fibrosis and Anti- Oxidative Stress Effects in Sprague-Dawley Rats

Heart Failure (HF) is an important public health problem as a result of its high morbidity and poor prognosis [1].

Developmental manganese, lead, and barren cage exposure have adverse long-term neurocognitive, behavioral and monoamine effects in Sprague-Dawley rats

Developmental stress, including low socioeconomic status (SES), can induce dysregulation of the hypothalamic-pituitary-adrenal axis and result in long-term changes in stress reactivity. Children in lower SES households experience more stress and are more likely to be exposed to environmental neurotoxins such as lead (Pb) and manganese (Mn) than children in higher SES households. Co-exposure to stress, Pb, and Mn during early development may increase the risk of central nervous system dysfunction compared with unexposed children. To investigate the potential interaction of these factors, Sprague-Dawley rats were bred, and litters born in-house were culled on postnatal day (P)1 to 6 males and 6 females. One male and female within each litter were assigned to one of the following groups: 0 (vehicle), 10 mg/kg Pb, 100 mg/kg Mn, or 10 mg/kg Pb + 100 mg/kg Mn (PbMn), water gavage, and handled only from P4–28 with half the litters reared in cages with standard bedding (29 litters) and half with no bedding (Barren; 27 litters). Mn and PbMn groups had decreased anxiety, reduced acoustic startle, initial open-field hypoactivity, increased activity following (+)-methamphetamine, deficits in egocentric learning in the Cincinnati water maze (CWM), and deficits in latent inhibition conditioning. Pb increased anxiety and reduced open-field activity. Barren-reared rats had decreased anxiety, CWM deficits, increased startle, and initial open-field hyperactivity. Mn, PbMn, Pb Barren-reared groups had impaired Morris water maze performance. Pb altered neostriatal serotonin and norepinephrine, Mn increased hippocampal serotonin in males, Mn + Barren-rearing increased neostriatal serotonin, and Barren-rearing decreased neostriatal dopamine in males. At the doses used here, most effects were in the Mn and PbMn groups. Few interactions between Mn, Pb, and rearing stress were found, indicating that the interaction of these three variables is not as impactful as hypothesized.

Nutrient and Chemical Analysis of Fruiting Bodies of a Cultivar of the Chinese Caterpillar Mushroom, Ophiocordyceps sinensis (Ascomycetes).

A cultivar of fruiting bodies of Ophiocordyceps sinensis (FBOS; OCS02) was analyzed for nutrients, bioactive compounds, and heavy metal content to showcase its potential as a competitive, sustainable, and safe alternative to wild types and other cultivars. A previous 28-day subacute toxicity study showed that doses up to 1 g · kg-1 did not cause any adverse effects in Sprague-Dawley rats. The OCS02 cultivar contained large amounts of cordycepin, polysaccharides, and essential and semi-essential amino acids (0.66, 482.80, 99.02, and 101.04 g · kg-1, respectively) compared with levels reported in wild types and in cultivated mycelia. β-1,3/1,6-glucan content was considerably high at 342.50 g · kg-1. The potassium level (5.14 g kg-1) tied in well with the low sodium content (0.121 g · kg-1)-6 times lower than amounts in wild types. We found no detectable levels of heavy metals such as lead, arsenic, cadmium, and mercury. The major amino acids found in FBOS (0CS02 cultivar) were arginine, lysine, serine, and threonine at 45.20, 20.30, 18.60, and 18.20 g · kg-1, respectively. The cultivated FBOS (OCS02 cultivar) is a comparable alternative to wild-type and other cultivated strains of O. sinensis. It has potential as a nutraceutical to meet market demand.

Bio-functionalized gold nanoparticles: Benign effect in Sprague-Dawley rats by intravenous administration.

Gold nanoparticles offer a great promise in clinical research. Despite various applications of the metal nanoparticles it is challenging to implement in vivo in clinical applications. This aspect is deprived of understanding the biological mechanisms that occurs in the cells. In this report we have evaluated application of AuNP on the safety profile at different doses (100, 200, and 500 μg/kg Bwt/day) on intravenous administration in rats regularly for 28 days. The study was performed based on the OECD test guideline 407. No clinical signs and mortalities were observed in any groups of rat treated with AuNP. No evidence of toxicity was observed in any of the diverse studies performed which is noteworthy. The study includes survival, behavior, animal weight, organ morphology, blood biochemistry and tissue histology. The results indicate that tissue accumulation pattern of gold nanoparticles depends on the surface, size and doses of the nanoparticle. The accumulation of the particles does not produce subacute physiological damage.

Subchronic feeding study of high-free-lysine transgenic rice in Sprague-Dawley rats

Lysine is considered to be the first essential amino acid in rice. An elite High-Free-Lysine transgenic line HFL1 was previously produced by metabolic engineering to regulate lysine metabolism. In this study, a 90-day toxicology experiment was undertaken to investigate the potential health effect of feeding different doses of HFL1 rice to Sprague-Dawley rats. During the trial, body weight gain, food consumption and food efficiency were recorded, and no adverse effect was observed in rats fed transgenic (T) rice diets compared with non-transgenic (N) or control diets. At both midterm and final assessments, hematological parameters and serum chemistry were measured, and organ weights and histopathology were examined at the end of the trial. There was no diet-related difference in most hematological or serum chemistry parameters or organ weights between rats fed the T diets and those fed the N or control diets. Some parameters were found to differ between T groups and their corresponding N and/or control groups, but no adverse histological effect was observed. Taken together, the data from the current trial demonstrates that high lysine transgenic rice led to no adverse effect in Sprague-Dawley rats given a diet containing up to 70% HFL1 rice in 90 days.

Strain-specific programming of prenatal ethanol exposure across generations.

Behavioral consequences of prenatal alcohol exposure (PAE) can be transmitted from in utero-exposed F1 generation to their F2 offspring. This type of transmission is modulated by genetic and epigenetic mechanisms. This study investigated the intergenerational consequences of prenatal exposure to a low ethanol dose (1g/kg) during gestational days 17-20, on ethanol-induced hypnosis in adolescent male F1 and F2 generations, in two strains of rats. Adolescent Long-Evans and Sprague-Dawley male rats were tested for sensitivity to ethanol-induced hypnosis at a 3.5-g/kg or 4.5-g/kg ethanol dose using the loss of righting reflex (LORR) paradigm. We hypothesized that PAE would attenuate sensitivity to ethanol-induced hypnosis in the ethanol-exposed animals in these two strains and in both generations. Interestingly, we only found this effect in Sprague-Dawley rats. Lastly, we investigated PAE related changes in expression of GABAA receptor α1, α4, and δ subunits in the cerebral cortex of the PAE sensitive Sprague-Dawley strain. We hypothesized a reduction in the cerebral cortex GABAA receptor subunits' expression in the F1 and F2 PAE groups compared to control animals. GABAA receptor α1, α4, and δ subunits protein expressions were quantified in the cerebral cortex of F1 and F2 male adolescents by western blotting. PAE did not alter cerebral cortical GABAA receptor subunit expressions in the F1 generation, but it decreased GABAA receptor α4 and δ subunits' expressions in the F2 generation, and had a tendency to decrease α1 subunit expression. We also found correlations between some of the subunits in both generations. These strain-dependent vulnerabilities to ethanol sensitivity, and intergenerational PAE-mediated changes in sensitivity to alcohol indicate that genetic and epigenetic factors interact to determine the outcomes of PAE animals and their offspring.

Life-span exposure to sinusoidal-50 Hz magnetic field and acute low-dose γ radiation induce carcinogenic effects in Sprague-Dawley rats

Background In 2002 the International Agency for Research on Cancer classified extremely low frequency magnetic fields (ELFMF) as a possible carcinogen on the basis of epidemiological evidence. Experimental bioassays on rats and mice performed up to now on ELFMF alone or in association with known carcinogens have failed to provide conclusive confirmation.Objectives To study the carcinogenic effects of combined exposure to sinusoidal-50 Hz (S-50Hz) magnetic fields and acute γ radiation in Sprague-Dawley rats.Methods We studied groups of male and female Sprague-Dawley rats exposed from prenatal life until natural death to 20 or 1000 μT S-50Hz MF and also to 0.1 Gy γ radiation delivered as a single acute exposure at 6 weeks of age.Results The results of the study showed significant carcinogenic effects for the mammary gland in males and females and a significant increased incidence of malignant schwannomas of the heart as well as increased incidence of lymphomas/leukemias in males.Conclusions These results call for a re-evaluation of the safety of non-ionizing radiation.

The novel ketamine analog methoxetamine produces dissociative-like behavioral effects in rodents.

Methoxetamine (MXE) is a ketamine analog sold online that has been subject to widespread abuse for its dissociative and hallucinogenic effects. Previous studies have shown that MXE has high affinity for the phencyclidine (PCP) binding site located within the channel pore of the NMDA receptor (NMDAR), but little is known about its behavioral effects. Dissociative anesthetics such as ketamine and PCP produce a characteristic behavioral profile in rats that includes locomotor hyperactivity and disruption of prepulse inhibition (PPI) of acoustic startle. The goal of the present investigation was to determine whether MXE produces PCP-like effects in Sprague-Dawley rats using the PPI paradigm and the behavioral pattern monitor (BPM), which enables analyses of patterns of locomotor activity and investigatory behavior. PPI studies were conducted with several other uncompetitive NMDAR antagonists that produce dissociative effects in humans, including PCP, the S-(+) and R-(-) isomers of ketamine, and N-allylnormetazocine (NANM; SKF-10,047). MXE disrupted PPI when administered at 3 and 10mg/kg SC. The rank order of potency of MXE and the other test compounds in the PPI paradigm (PCP > MXE > S-(+)-ketamine > NANM > R-(-)-ketamine) parallels their affinities for the PCP binding site reported in the literature. When tested in the BPM, 10mg/kg MXE induced locomotor hyperactivity, reduced the number of rearings, increased the roughness of locomotor paths, and produced perseverative patterns of locomotion. Administration of PCP (2.25 and 6.75mg/kg, SC) produced a similar profile of effects in the BPM. These results indicate that MXE produces a behavioral profile similar to that of other psychotomimetic uncompetitive NMDAR antagonists. Our findings support the classification of MXE as a dissociative drug and suggest that it likely has effects and abuse potential similar to that of PCP and ketamine.

ANTRODIA CINNAMOMEA EXTRACT ATTENUATES CARBON TETRACHLORIDE-INDUCED CHRONIC LIVER FIBROSIS IN SPRAGUE-DAWLEY RATS

Background: Antrodia cinnamomea (AC) mycelia have been traditionally used by majority of the indigenous populace in Taiwan for symptoms including treating alcohol intoxication. Other beneficial effects have been studied at some point. The present study evaluated the hepato-protection effects in Sprague-Dawley rats.&#x0D; Methods: The model used carbon tetrachloride (CCl4) to induce a chronic liver injury in male rats. Animals were treated with silymarin 200 mg/kg and AC mycelia at doses of 206, 619 and 1,032 mg/kg. The effects of AC on hepatic enzyme markers alanine and aspartate aminotransferase (ALT and AST) and other biochemical parameters were measured in the CCl4 -induced rats. &#x0D; Results: AC demonstrated a hepato-protective effect by decreasing ALT and AST levels and increasing albumin levels in CCl4 treated rats. The effects of AC on the activity of antioxidant enzymes were evaluated. AC administration restored the activities of catalase (CAT), glutathione peroxidase (GPx) and glutathione reductase (GrD). The degree of liver fibrosis was significantly reduced by AC administration in CCl4 -treated rats. &#x0D; Conclusion: These results suggest that AC could protect the hepatocytes from CCl4 -induced liver injury likely via an antioxidant mechanism.

Acute and chronic systemic CB1 cannabinoid receptor blockade improves blood pressure regulation and metabolic profile in hypertensive (mRen2)27 rats.

We investigated acute and chronic effects of CB1 cannabinoid receptor blockade in renin‐angiotensin system‐dependent hypertension using rimonabant (SR141716A), an orally active antagonist with central and peripheral actions. In transgenic (mRen2)27 rats, a model of angiotensin II‐dependent hypertension with increased body mass and insulin resistance, acute systemic blockade of CB1 receptors significantly reduced blood pressure within 90 min but had no effect in Sprague‐Dawley rats. No changes in metabolic hormones occurred with the acute treatment. During chronic CB1 receptor blockade, (mRen2)27 rats received daily oral administration of SR141716A (10 mg/kg/day) for 28 days. Systolic blood pressure was significantly reduced within 24 h, and at Day 21 of treatment values were 173 mmHg in vehicle versus 149 mmHg in drug‐treated rats (P < 0.01). This accompanied lower cumulative weight gain (22 vs. 42 g vehicle; P < 0.001), fat mass (2.0 vs. 2.9% of body weight; P < 0.05), and serum leptin (2.8 vs. 6.0 ng/mL; P < 0.05) and insulin (1.0 vs. 1.9 ng/mL; P < 0.01), following an initial transient decrease in food consumption. Conscious hemodynamic recordings indicate twofold increases occurred in spontaneous baroreflex sensitivity (P < 0.05) and heart rate variability (P < 0.01), measures of cardiac vagal tone. The beneficial actions of CB1 receptor blockade in (mRen2)27 rats support the interpretation that an upregulated endocannabinoid system contributes to hypertension and impaired autonomic function in this angiotensin II‐dependent model. We conclude that systemic CB1 receptor blockade may be an effective therapy for angiotensin II‐dependent hypertension and associated metabolic syndrome.

Effect of resistant starch on HCl/ethanol-induced gastric injury in rats

Three types of resistant starch (RS) products were purchased for the evaluation of gastric injury preventive effect in Sprague-Dawley rats. We used an animal model to check for gastric injury preventive activities of these RS products in vivo. RS3 reduced the levels of serum proinflammatory cytokines of IL-6 and TNF-α as compared to those of RS2 and RS4. The gastric secretion volumes from high to low order were control rats, RS2-treated rats, RS4-treated rats, RS3-treated rats, and normal rats, whereas pH levels of gastric juice showed the opposite trend. The gastric injury level was significantly decreased by RS, demonstrating its anti-inflammatory properties, with RS3 showing the best anti-inflammatory effect. Gastric tissues of RS3 group rats showed significantly decreased mRNA and protein expression levels of inflammation-related genes of iNOS, COX-2, TNF-α, and IL-1β compared with the control group, as shown by RT-PCR and Western blot analyses. These results suggest that RS shows a gastric injury preventive effect, with RS3 showing the best inhibitory effect on gastric injury.

Short‐term and long‐term effects of excessive consumption of saturated fats and/or sucrose on metabolic variables in Sprague Dawley rats: a pilot study

Feeding high-fat and/or high-sugar diets to rats leads to a change in markers of metabolic syndrome. However, types and amounts of fat and sugar as well as the length of the experiment for establishing diet-induced metabolic syndrome in the Sprague Dawley (SD) rat model remain uncertain. This study was designed to investigate the effects in SD rats of consuming excess lard, sucrose or a combination of lard and sucrose for a short (4 week) or long (8 week) period of time. Consumption of the high-fat high-sugar (HFHS) diet significantly increased weight gain and abdominal fat weights (P < 0.05), and the rats also began to develop signs of impaired glucose tolerance and had increased fasting blood lipids glucose and insulin concentrations. The high-fat (HF) diet mainly affected weight gain and fat deposition, whereas the high-sugar (HS) diet induced glucose intolerance but not the obesity-related parameters. Control rats showed a tendency towards insulin resistance and glucose intolerance when fed for a long-term period. The lard plus sucrose-based HFHS diet is the most efficient one for inducing signs of metabolic syndrome, and SD rats fed this diet for 8 weeks successfully develop obesity and insulin resistance, which can be used as a model for metabolic syndrome research.

Effect of Ambient Temperature on the Thermoregulatory and Locomotor Stimulant Effects of 4-Methylmethcathinone in Wistar and Sprague-Dawley Rats

The drug 4-methylmethcathinone (4-MMC; aka, mephedrone, MMCAT, “plant food”, “bath salts”) is a recent addition to the list of popular recreational psychomotor-stimulant compounds. Relatively little information about this drug is available in the scientific literature, but popular media reports have driven recent drug control actions in the UK and several US States. Online user reports of subjective similarity to 3,4-methylenedioxymethamphetamine (MDMA, “Ecstasy”) prompted the current investigation of the thermoregulatory and locomotor effects of 4-MMC. Male Wistar and Sprague-Dawley rats were monitored after subcutaneous administration of 4-MMC (1–10 mg/kg ) using an implantable radiotelemetry system under conditions of low (23°C) and high (27°C) ambient temperature. A reliable reduction of body temperature was produced by 4-MMC in Wistar rats at 23°C or 27°C with only minimal effect in Sprague-Dawley rats. Increased locomotor activity was observed after 4-MMC administration in both strains with significantly more activity produced in the Sprague-Dawley strain. The 10 mg/kg s.c. dose evoked greater increase in extracellular serotonin, compared with dopamine, in the nucleus accumbens. Follow-up studies confirmed that the degree of locomotor stimulation produced by 10 mg/kg 4-MMC was nearly identical to that produced by 1 mg/kg d-methamphetamine in each strain. Furthermore, hypothermia produced by the serotonin 1A/7 receptor agonist 8-hydroxy-N,N-dipropyl-2-aminotetralin (8-OH-DPAT) was similar in each strain. These results show that the cathinone analog 4-MMC exhibits thermoregulatory and locomotor properties that are distinct from those established for methamphetamine or MDMA in prior work, despite recent evidence of neuropharmacological similarity with MDMA.

국화로부터 추출한 천연염료에 대한 급성경구독성 및 피부자극성 시험에 대한 연구

본 연구는 SD 계통의 랫드에서 국화 염료인 백색국화, 백색국화 잎과 줄기, 황색국화의 급성경구독성 및 피부자극성을 평가하기 위해서 시행하였다. 수컷 랫드에 처치한 물질은 백색국화, 백색국화 잎과 줄기, 황색국화를 각각 1 ml/kg, 2 ml/kg를 D.W에 용해시켜 단회 경구 투여하였으며, 수컷 SD rats에 투여 후 14일 동안 관찰하였으며, 피부자극성 시험은 피부의 찰과 및 비찰과부의 대조부, 처치부에 국화 염료를 처치하여 3일 동안 관찰하였다. 단회 경구 투여 및 피부 자극성 시험 후 국화 염료의 안전성을 확인하기 위해 체중과 사료 섭취량, 임상증상, 안과학적 검사, 사망률, 피부자극성을 관찰하고, 랫드 피부에서의 병리조직학적 변화를 관찰하였다. 체중, 사료섭취량, 병리조직학적 변화가 대조군과 비교시 유의적인 변화가 나타나지 않았다. 또한 피부자극성을 확인 한 결과 1차 자극 지수가 0으로 비자극성 물질로 분류되었다. 따라서 본 연구를 통하여 국화에서 추출한 염료가 급성 경구독성 시 안전한 물질이며, 피부 자극성을 야기 하지않는 물질로 평가된다. This study was designed to evaluate to acute oral toxicity and skin irritation of Chrysanthemum dye in Sprague-Dawley (SD) rats. SD rats were orally treated with Chrysanthemum dye at a dose of 0, 1 and 2 ml/kg body weight. After oral administration, the rats were observed for 14days. In primary skin irritation test, SD rats were dermally treated with Chrysanthemum dye and observed for 3 days. To ensure the safety of Chrysanthemum dye such as the following were observed and tested. We examined the body weight, the feed intake, the clinical signs, the ophthalmological test, the histopathological test, the mortality and skin irritation. As a result, no significant differences were found in body weight, feed intake and histopathological test between control and Chrysanthemum dye treated group. In the result of skin irritation test, Chrysanthemum dye did not induce erythema and edema after topical application. Primary irritation index was "0" in the test. Therefore, it is suggested that Chrysanthemum dye has no effect on acute toxicity and side effect in SD rats and is non-irritant material based on the score "0" of primary irritation index.