Neuroprotective Effects of a Butanol Fraction of Rosa hybrida Petals in a Middle Cerebral Artery Occlusion Model

The neuroprotective effects of a butanol fraction of white rose petal extract (WRPE-BF) were investigated in a middle cerebral artery occlusion (MCAO) model. Seven week-old male rats were orally administered WRPE-BF for 2 weeks and subjected to MCAO for 2 h, followed by reperfusion. Twenty-four h later, MCAO-induced behavioral dysfunctions were markedly improved in a dose-dependent manner by pretreatment with WRPE-BF. Moreover, higher dose of WRPE-BF not only decreased infarction area but also effectively reduced astrogliosis. The expression of inducible nitric oxide synthase, cyclooxygenase-2, and glial fibrillary acidic protein in MCAO model were markedly inhibited by WRPE-BF treatment. Notably, WRPE-BF decreased nitric oxide and malondialdehyde levels in the striatum and subventricular zone of stroke-challenged brains. These data suggested that WRPE-BF may exert its neuroprotective effects via anti-oxidative and anti-inflammatory activities against ischemia-reperfusion brain injury and could be a good candidate as a therapeutic target for ischemic stroke.

Anti-Helicobacter pylori effects of IgY from egg york of immunized hens / 한국실험동물학회지

Effects of egg york containing IgY specific for Helicobacter pylori on the bacterial growth and intragastric infection were investigated in comparison with a proton-pump inhibitor pantoprazole. For in vitro anti-bacterial activity test, H. pylori (1x108 CFU/mL) was incubated with a serially diluted IgY for 3 days. As a result, IgY fully inhibited the bacterial growth at 16 mg/mL, which was determined to a minimal inhibitory concentration. In vivo elimination study, male C57BL/6 mice were infected with the bacteria by intragastric inoculation (1x108 CFU/mouse) 3 times at 2-day intervals, and 2 weeks later, orally treated twice a day with 50, 100, 200 or 500 mg/kg IgY for 18 days. After the final administration, biopsy sample of the gastric mucosa was assayed for the bacterial identification via urease, oxidase, catalase, nitrate reduction and H2S tests in addition to microscopic examination for mucosal inflammation. In CLO kit test, 75, 50, 12.5 and 12.5% of the animals revealed positive reaction following treatment with 50, 100, 200 and 500 mg/kg IgY, respectively, resulting in a superior efficacy at 200 mg/kg than 30 mg/kg pantoprazole that displayed 75% elimination. The CLO test results were confirmed by bacterial identification. Microscopic examination revealed that H. pylori infection caused severe gastric mucosal inflammation, which were not observed in the CLO-negative mice following treatment with IgY or pantoprazole. Taken together, IgY inhibited the growth of H. pylori, and improved gastritis and villi injuries by eliminating the bacteria from the stomach. The results indicate that IgY could be a good candidate overcoming tolerance of antibiotics for the treatment of H. pylori-mediated gastric ulcers.

Increased Nephrotoxicity after Combined Administration of Melamine and Cyanuric Acid in Rats / 한국실험동물학회지

Renal toxicity by melamine in combination with cyanuric acid (1:1) was investigated. Male rats were orally administered melamine plus cyanuric acid (5, 50 or 400 mg/kg each) for 3 days. In contrast to a negligible effect by melamine alone (50 mg/kg, a no-observed-adverse-effect-level: NOAEL), co-administration with cyanuric acid markedly increased the concentrations of blood urea nitrogen and creatinine, as well as kidney weight. A high dose (400 mg/kg) of melamine plus cyanuric acid induced more severe kidney toxicity. The increased blood parameters for kidney toxicity and organ weight lasted longer than 4 days. Combined treatment with melamine and cyanuric acid (50-400 mg/kg each) resulted in many gold-brown crystals and toxic lesions in renal tubules, which were not observed in animals treated with melamine alone (50 mg/kg). These results indicate that only a 3-day exposure to melamine in combination with cyanuric acid causes severe renal damage, even at a NOAEL for melamine found in a 13-week toxicity study. Therefore, it is suggested that the tolerable daily intake or regulatory/management levels of melamine need to be re-considered for cases of co-exposure with cyanuric acid.

Different Antiulcer Activities of Pantoprazole in Stress, Alcohol and Pylorus Ligation-Induced Ulcer Models / 한국실험동물학회지

Antiulcer effects of pantoprazole, a proton-pump inhibitor, on water-immersion restraint stress (WIRS)-, alcohol (ethanol)- and pylorus ligation-induced gastric ulcers were investigated in male rats. Rats were orally administered with pantoprazole 30 min prior to exposure to various types of ulcer inducers. In stress-induced ulcer model, rats were subjected to WIRS at 22degrees C for 4 hours, and the degree of ulcer (in mm) was evaluated. In alcohol-induced ulcer model, rats were orally administered with pure (100%) ethanol (1 mL/kg), and the ulcer lesions were measured 1 hour after ethanol challenge. In pylorus ligation-induced ulcer model, rats were subjected to pylorus ligation, and the degree of erosions and ulcers was scored 17 hours after the operation. Pantoprazole attenuated the ulcer lesions induced by WIRS in a dose-dependent manner, exhibiting a median effective dose (ED50) value of 0.78 mg/kg. By comparison, pantoprazole was effective at relatively-high doses for the improvement of ethanol-induced ulcers, showing an ED50 value of 20.5 mg/kg. Notably, pantoprazole was practically ineffective (ED50>50.0) in pylorus ligation model. Taken together, it was confirmed that pantoprazole showed inhibitory activity on gastric ulcers induced by stress and alcohol, but was ineffective on pylorus ligation-induced ulcer. Therefore, the results indicate that proton-pump inhibitors including pantoprazole might reveal highly-different effects according to the type of ulcer inducers, and that the prescription of antiulcer agents should be carefully selected.

Effects of Sigma Anti-bonding Molecule Calcium Carbonate on bone turnover and calcium balance in ovariectomized rats / 한국실험동물학회지

This study was conducted to evaluate the effect of Sigma Anti-bonding Molecule Calcium Carbonate (SAC) as therapy for ovariectomy-induced osteoporosis in rats. Three weeks after surgery, fifteen ovariectomized Sprague-Dawley rats were divided randomly into 3 groups: sham-operated group (sham), ovariectomized group (OVX) and SAC-treatment group (OVX+SAC). The OVX+SAC group was given drinking water containing 0.0012% SAC for 12 weeks. Bone breaking force and mineralization as well as blood parameters related to the bone metabolism were analyzed. In OVX animals, blood concentration of 17beta-estradiol decreased significantly, while osteocalcin and type I collagen C-terminal telopeptides (CTx) increased. Breaking force, bone mineral density (BMD), calcium and phosphorus in femurs, as well as uterine and vaginal weights, decreased significantly following OVX. However, SAC treatment (0.0012% in drinking water) not only remarkably restored the decreased 17beta-estradiol and increased osteocalcin and CTx concentrations, but also recovered decreased femoral breaking force, BMD, calcium and phosphorus, although it did not reversed reproductive organ weights. It is suggested that SAC effectively improve bone density by preventing bone turnover mediated osteocalcin, CTx and minerals, and that it could be a potential candidate for therapy or prevention of postmenopausal osteoporosis.

Animal Models of Periventricular Leukomalacia / 한국실험동물학회지

Periventricular leukomalacia, specifically characterized as white matter injury, in neonates is strongly associated with the damage of pre-myelinating oligodendrocytes. Clinical data suggest that hypoxia-ischemia during delivery and intrauterine or neonatal infection-inflammation are important factors in the etiology of periventricular leukomalacia including cerebral palsy, a serious case exhibiting neurobehavioral deficits of periventricular leukomalacia. In order to explore the pathophysiological mechanisms of white matter injury and to better understand how infectious agents may affect the vulnerability of the immature brain to injury, novel animal models have been developed using hypoperfusion, microbes or bacterial products (lipopolysaccharide) and excitotoxins. Such efforts have developed rat models that produce predominantly white matter lesions by adopting combined hypoxia-ischemia technique on postnatal days 1-7, in which unilateral or bilateral carotid arteries of animals are occluded (ischemia) followed by 1-2 hour exposure to 6-8% oxygen environment (hypoxia). Furthermore, low doses of lipopolysaccharide that by themselves have no adverse-effects in 7-day-old rats, dramatically increase brain injury to hypoxic-ischemic challenge, implying that inflammation sensitizes the immature central nervous system. Therefore, among numerous models of periventricular leukomalacia, combination of hypoxia-ischemia-lipopolysaccharide might be one of the most-acceptable rodent models to induce extensive white matter injury and ensuing neurobehavioral deficits for the evaluation of candidate therapeutics.

Experimental Models of Cerebral Palsy in Infant Rats / 한국실험동물학회지

Brain damage resulting from perinatal cerebral hypoxia and ischemia is a major cause of acute mortality and neurological disabilities, including cerebral palsy (CP) and cognitive dysfunction. In order to establish an experimental hypoxia-ischemia (HI) model of CP for the screening of therapeutics, we operated bilateral common carotid artery ligation (BCAO) and monolateral carotid artery occlusion (MCAO), followed by 15 min of hypoxia (8% oxygen) in 4-day-old rats, and evaluated neurobehavioral disorders. After surgery, the survival rates of male and female BCAO rats were 33.3 and 7.1%, respectively, whereas 100% and 82.4% MCAO rats survived. In neurobehavioral performances, both male and female BCAO rats showed delayed achievement of righting reflex, in contrast to a negligible effect in MACO animals. However, both BCAO and MCAO rats exhibited impairment of cliff avoidance performances, although the physical dysfunction was more severe in BCAO than in MCAO. In global locomotor activity, MCAO rats also displayed decreased fast-moving time comparable BCAO animals, and increased resting and slow-moving times. In addition, MCAO rats showed marked learning and memory deficit in passive avoidance performances, similar to BCAO animals. From immunostaining analyses, severe degradation and loss of myelin basic proteins were observed in the brain of BCAO rats, in contrast to a mild aggregation in MCAO animals. Therefore, it is suggested that MCAO should be a more suitable CP model than BCAO, based on the high survival rate, relatively-mild brain injury, and enough neurobehavioral disorders for the research on preventive and therapeutic compounds.

Antioxidative and Antidiarrheal Effects of Persimmon Extracts / 한국실험동물학회지

Since oxidative stresses are involved in gastroenteritis and diarrhea, we investigated antioxidative and antidiarrheal activities of persimmon flesh extract (PFE) and persimmon calyx extract (PCE) in vitro and in vivo, respectively. PCE significantly scavenged 1,1-diphenyl-2-picrylhydrazyl hydrate and 2,2'-azinobis (3-ethylbenzthiazoline-6-sulfonic acid) from 500 microg/mL, although PFE was ineffective. In addition, PFE and PCE exhibited strong nitric oxide-scavenging effects from 1 microg/mL, in which PCE was superior to ascorbic acid (50 microM). Furthermore, PFE and PCE significantly inhibited FeCl3-induced lipid peroxidation as well as Cu2+/H2O2-induced protein oxidation from 10 microg/mL. In vivo charcoal-propulsion assay, in contrast to a negligible effect of PFE, treatment with PCE (160-500 mg/kg) markedly inhibited intestinal motility. The results indicate that extracts of persimmon, especially PCE, possess antioxidative, antiinflammatory and antidiarrheal activities. Therefore, it is suggested that persimmon extracts could be used for the relief of gastroenteritis and diarrhea.