Byong-il Choi

Antiteratogenic effect of resveratrol in mice exposed in utero to 2,3,7,8-tetrachlorodibenzo-p-dioxin

The effect of resveratrol, an aryl hydrocarbon receptor antagonist, on the teratogenicity induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) was investigated. Pregnant C57BL/6J mice were orally administered resveratrol (50 mg/kg) for 6 consecutive days, from gestational day (GD) 8 to GD13, followed by an oral challenge with TCDD (14 mug/kg) on GD12. TCDD caused severe fetal malformations including cleft palate (40.7%), renal pelvic dilatation (100%, mean score 3.060), and ureteric dilatation (100%, mean score 3.210) and tortuosity (95.1%). Resveratrol significantly reduced both the incidence of TCDD-induced cleft palate to 18.4% and the degrees of renal pelvic and ureteric dilatations caused by TCDD. The results suggest that pretreatment with resveratrol might bring a beneficial outcome for reducing the incidence and severity of fetal malformations caused by TCDD exposure in utero.

Neurobehavioural deficits correlate with the cerebral infarction volume of stroke animals: A comparative study on ischaemia-reperfusion and photothrombosis models

The study investigated the correlation between infarction areas and behavioural deficits in middle cerebral artery occlusion (MCAO) and photothrombosis stroke models. In the MCAO model, a 0.38 mm-diameter silicone-coated thread was introduced through the left external carotid artery and advanced 18 mm via the internal carotid artery to the origin of middle cerebral artery of male Sprague-Dawley rats weighing 300-350 g. The thread was removed for reperfusion after occlusion for 0.5, 1 or 2h. In the photothrombosis model, after a midline incision on the scalp, a focused light (10,000 lux, 6 mm-diameter) was delivered 1mm anterior to the bregma and 3mm left of the midline for 5, 10 or 20 min. During the first 2 min of irradiation, Rose Bengal dye (30 mg/kg) was injected intravenously. Twenty four hours post-surgery, the animals were subjected to neurological scoring and behavioural performances, and were sacrificed for macroscopic and microscopic examinations of brain injury. Total infarction volumes in the MCAO model rats increased in an occlusion time-dependent manner, while the infarction volumes in photothrombosis model rats plateaued relatively quickly with no time-dependent increase. The MCAO model displayed neurological scores and behavioural deficits that correlated well with infarction volumes, while relatively poor correlation between infarction volume and neurobehavioural abnormalities was evident in the photothrombosis model. The results indicate the suitability of the MCAO model for studies on preventive or therapeutic compounds related to functional recovery, although the photothrombosis model might be useful to generate focused lesions leading to the location-related behavioural changes.

Fermentation Filtrates of Rubus coreanus Relax the Corpus Cavernosum and Increase Sperm Count and Motility

We investigated the effects of fermentation filtrates from Rubus coreanus on the function of the male reproductive system. We performed an ex vivo study to determine if the candidate compounds relax isolated New Zealand white rabbit corpus cavernosum, which were precontracted by phenylephrine (5 x 10(-5) M). The results reveal that the filtrates of the reddish-purple (FRRC) and green (FGRC) R. coreanus exerted concentration-dependent relaxing effects, leading to median effective concentrations of 4.53 mg/mL and >10 mg/mL, respectively. For the in vivo study, male ICR mice were orally administered FRRC or FGRC (100 or 500 mg/kg) for 28 days, and the reproductive organ weights, serum testosterone level, cauda epididymal sperm counts, and motility were analyzed. Both the FRRC and FGRC had no significant effect on the reproductive organ weights; however, FRRC (100 or 500 mg/kg) enhanced testosterone levels and especially sperm counts at the higher dose (500 mg/kg). In comparison, FGRC increased hormone levels and sperm counts at a relatively low dose (100 mg/kg). In summary, it is proposed that the crude fermentation filtrates of ripe R. coreanus have positive effects on the function of the male reproductive system by triggering a penile erection, enhancing serum testosterone levels, and increasing epididymal sperm counts.

Debilitating stresses do not increase blood–brain barrier permeability: Lack of the involvement of corticosteroids

The involvement of corticosteroids in stress-induced change in blood-brain barrier (BBB) permeability was investigated. Mice were adrenalectomized and administered with pyridostigmine bromide (PB) or Evans blue, markers of BBB penetration, followed by 18-h cold-restraint stress (CRS). Rats were administered with mifepristone, a corticosteroid receptor blocker, and the markers, followed by 4-h water immersion-restraint stress (WIRS). Separately, soman was administered to induce seizures-mediated BBB opening. CRS did not induce PB and Evans blue penetration, which were not affected by adrenalectomy. Also, the markers were not detected in the brain of rats subjected to WIRS, regardless of the treatment of mifepristone. In comparison, 1-h epileptic seizures increased the penetration of Evans blue by 875%. The results suggest that in contrast to seizure-related BBB opening, profound stresses do not practically increase the BBB permeability, and that corticosteroids are not involved in the stress-induced BBB penetration of charged chemicals and albumin-dye complex.