Green tea ameliorates recognition memory defects in acute radiation syndrome caused by gamma irradiation / 동물의과학연구지

An evidence suggests that even low-dose irradiation can lead to progressive cognitive decline as well as memory deficits in both humans and experimental animals in part due to hippocampal dysfunction. To determine whether or not green tea (GT) and epigallocatechin gallate (EGCG) could attenuate memory impairment as well as suppress hippocampal neurogenesis, passive avoidance and object recognition memory test as well as TUNEL assay and immunohistochemical detection with markers of neurogenesis (Ki-67 and doublecortin (DCX)) were performed using adult mice treated with relatively low-dose gamma irradiation (2.0 Gy). GT was administered intraperitonially at a dosage of 50 mg/kg of body weight at 36 and 12 hr preirradiation and at 30 minutes post-irradiation, or orally at a dosage of 250 mg/kg of body weight/day for 7 days before autopsy. EGCG (25 mg/kg of body weight) was administered intraperitonially at 36 and 12 hr pre-irradiation and at 30 minutes post-irradiation. In the passive avoidance and object recognition memory test, mice trained for 1 day after acute irradiation (2 Gy) showed significant memory deficits compared with sham controls. The number of TUNEL-positive apoptotic nuclei in the dentate gyrus increased by 12 h after irradiation. In addition, the numbers of Ki-67- and DCX-positive cells significantly decreased. GT treatment prior to irradiation attenuated memory defects, blocked apoptotic death, as well as reduced the number of DCX-positive cells. Therefore, GT may attenuate memory defects in adult mice exposed to a relatively low dose of radiation possibly by inhibiting the detrimental effects of irradiation on hippocampal neurogenesis.

Evaluation of effect of red ginseng on ovariectomy-induced bone loss in C3H/HeN mice / 동물의과학연구지

Panax ginseng, also known as Korean ginseng, has long been used as a broad tonic in Oriental medicine to augment vitality, health, and longevity, particularly in older people. This study investigated the effects of Korean red ginseng (RG) on bone loss in ovariectomized (OVX) mice. C3H/HeN mice (10-weeks-old) were divided into sham and OVX groups. OVX mice were treated with vehicle, 17beta-estradiol (E2), RG (oral administration, 250 mg/kg/day), or RG (intraperitoneal administration, 50 mg/kg/every other day) for 6 weeks. Serum E2 concentration and alkaline phosphatase (ALP) activity were measured. Tibiae were analyzed using microcomputed tomography. Biomechanical properties and osteoclast surface level were measured. There was no significant difference in the degree of grip strength, body weight, uterine weight, mechanical property, tibiae length, or tibiae weight between the OVX and RG-treated groups. Compared with the OVX group, the serum ALP level was significantly lower in the RG-treated groups. Serum E2 levels and osteoclast surface levels did not change between the OVX and RG-treated groups. RG could not preserve trabecular bone volume, trabecular bone number, trabecular separation, trabecular thickness, structure model index, or bone mineral density of the proximal tibiae metaphysic. In conclusion, there was no definite effect of RG on OVX-induced bone loss in C3H/HeN mice.

Establishment of a murine model for radiation-induced bone loss using micro-computed tomography in adult C3H/HeN mice / 한국실험동물학회지

Bone changes are common sequela of radiation therapy for cancer. The purpose of this study was to establish an experimental model of radiation-induced bone loss in adult mice using micro-computed tomography (microCT). The extent of changes following 2 Gy gamma irradiation (2 Gy/min) was studied at 4, 8, 12 or 16 weeks after exposure. Adult mice that received 1, 2, 4 or 6 Gy of gamma-rays were examined 12 weeks after irradiation. Tibiae were analyzed using microCT. Serum markers and biomechanical properties were measured and the osteoclast surface was examined. A significant loss of trabecular bone in tibiae was evident 12 weeks after exposure. Measurements performed after irradiation showed a dose-related decrease in trabecular bone volume fraction (BV/TV) and bone mineral density (BMD), respectively. The best-fitting dose-response curves were linear-quadratic. Taking the controls into accounts, the lines of best fit were as follows: BV/TV (%)= -0.071D2-1.799D+18.835 (r2=0.968, D=dose in Gy) and BMD (mg/cm3) = -3.547D2-14.8D+359.07 (r2=0.986, D=dose in Gy). Grip strength and body weight did not differ among the groups. No dose-dependent differences were apparent among the groups with regard to mechanical and anatomical properties of tibia, serum biochemical markers and osteoclast activity. The findings provide the basis required for better understanding of the results that will be obtained in any further studies of radiation-induced bone responses.

The micronucleus frequency in cytokinesis-blocked lymphocytes of cattle in the vicinity of a nuclear power plant

Cytogenetic and hematological analyses were performed on the peripheral blood lymphocytes (PBLs) obtained from Korean native cattle bred in the vicinity of three nuclear power plants (Wolsong, Uljin and Yeonggwang) and in a control area. The micronucleus (MN) rates for the cattle from the Wolsong, Uljin and Yeonggwang nuclear power plants and for the control area were 9.87 +/- 2.64, 8.90 +/- 3.84, 9.20 +/- 3.68 and 9.60 +/- 3.91 per 1,000 cytokinesis-blocked lymphocytes, respectively. The apparent difference is not statistically significant. The MN frequencies of PBLs from cattle bred in the four areas are within the background variation for this study. The MN frequencies and hematological values were similar regardless of whether the cattle were bred near a nuclear power plant or in the control area.