Neurobehavioral Assessment of Rats Exposed to Yttrium Nitrate during Development.

OBJECTIVE: The aim of this study was to assess the effects of yttrium nitrate on neurobehavioral development in Sprague-Dawley rats. METHODS: Dams were orally exposed to 0, 5, 15, or 45 mg/kg daily of yttrium nitrate from gestation day (GD) 6 to postnatal day (PND) 21. Body weight and food consumption were monitored weekly. Neurobehavior was assessed by developmental landmarks and reflexes, motor activity, hot plate, Rota-rod and cognitive tests. Additionally, brain weights were measured on PND 21 and 70. RESULTS: No significant difference was noted among all groups for maternal body weight and food consumption. All yttrium-exposed offspring showed an increase in body weight on PND 21; however, no significant difference in body weight for exposed pups versus controls was observed 2 weeks or more after the yttrium solution was discontinued. The groups given 5 mg/kg daily decreased significantly in the duration of female forelime grip strength and ambulation on PND 13. There was no significant difference between yttrium-exposed offspring and controls with respect to other behavioral ontogeny parameters and postnatal behavioral test results. CONCLUSION: Exposure of rats to yttrium nitrate in concentrations up to 45 mg/kg daily had no adverse effects on their neurobehavioral development.

Endocrine disruption of cadmium in rats using the OECD enhanced TG 407 test system.

OBJECTIVE: To evaluate the endocrine disrupting effects of cadmium (Cd) using OECD enhanced TG407 test guideline. METHODS: Sprague-Dawley (SD) rats were randomly divided into six groups and accordingly administered with 0, 1, 2.5, 5, 10, 20 mg/kg•BW/day of Cd by gavage for 28 days. Body weight, food consumption, hematology, biochemistry, sex hormone levels, urinary ß2-microglobulin, organ weights and histopathology and estrous cycle were detected. RESULTS: Cd could significantly decrease animals' body weight (P<0.05). Serum luteinizing hormone (LH) at 10-20 mg/kg•BW groups and testosterone (T) at 2.5 and 10 mg/kg•BW groups decreased significantly (P<0.05). However, no statistically significant change was found in urinary ß2-microglobulin among Cd-treatment groups (P>0.05). Endpoints related to female reproduction including uterus weight and histopathological change at 10-20 mg/kg•BW groups showed significant increase (P<0.05). While among male rats in 2.5, 10, 20 mg/kg•BW groups, weight of prostate, thyroids, and seminal vesicle glands significantly decreased (P<0.05). Moreover, no histopathological change was observed in kidney. CONCLUSION: Results suggested that Cd can cause endocrine disrupting effects in SD rats. Comparing with possible renal toxicity of Cd, its toxicity on endocrine system was more sensitive.

[Immunotoxicologic assessment of genetically modified drought-resistant wheat T349 with GmDREB1].

OBJECTIVE: To assess the immunotoxicologic effects of genetically modified drought resistant wheat T349 with GmDREB1 gene. METHODS: A total of 250 female BALB/c mice (6-8 week-old, weight 18-22 g) were divided into five large groups (50 mice for each large group) by body weight randomly. In each large group, the mice were divided into five groups (10 mice for each group) by body weight randomly, which were set as negative control group, common wheat group, parental wheat group, genetically modified wheat group and cyclophosphamide positive control group, respectively. Mice in negative control and positive control group were fed with feedstuff AIN-93G, mice in common wheat group, non-genetically modified parental wheat group and genetically modified wheat group were fed with feedstuffs added corresponding wheat (proportion up to 76%) for 30 days, then body weight, organ coefficient of spleen and thymus, peripheral blood lymphocytes phenotyping, serum cytokine, serum immunoglobulin, antibody plaque-forming cell (PFC), serum 50% hemolytic value (HC50), mitogen-induced splenocyte proliferation, delayed-type hypersensitivity (DTH) reaction and phagocytic activities of phagocytes were detected respectively. RESULTS: After 30 days raise, among negative control group, common wheat group, non-genetically modified parental wheat group, genetically modified wheat group and cyclophosphamide positive control group, mice body weight were (21.0±0.3), (20.4±0.7), (21.1±1.0), (21.1±1.0), (19.4±1.0) g, respectively (F=7.47, P<0.01); organ coefficient of spleen were (0.407±0.047)%, (0.390±0.028)%, (0.402±0.042)%, (0.421±0.041)%, (0.304±0.048)%, respectively (F=12.41, P<0.01); organ coefficient of thymus were (0.234±0.032)%, (0.246±0.028)%, (0.249±0.040)%, (0.234±0.034)%, (0.185±0.039)%, respectively (F=5.58, P<0.01); the percentage of T cell in peripheral blood were (70.43±4.44)%, (68.33±5.37)%, (73.04±2.68)%, (74.42±2.86)%, (90.42±1.66)%, respectively (F=57.51, P<0.01); the percentage of B cell were (13.89±3.19)%, (15.34±4.84)%, (13.06±4.22)%, (12.93±2.36)%, (3.01±0.96)%, respectively (F=12.79, P<0.01); the percentage of Th cell were (55.87±3.80)%, (55.24±4.60)%, (57.92±3.70)%, (59.57±2.54)%, (77.37±2.31)%, respectively (F=68.58, P<0.01);the Th/Ts ratio were 4.16±0.29, 4.73±0.96, 4.19±0.78, 4.52±0.40, 6.34±0.73, respectively (F=17.57, P<0.01);the serum IgG were (1046.38±210.67), (1065.49±297.22), (1517.73±299.52), (1576.67±241.92), (1155.88±167.05) µg/ml, respectively (F=10.53, P<0.01); the serum IgM were (333.83±18.97), (327.73±27.72), (367.47±27.18), (363.42±46.14), (278.71±24.42) µg/ml, respectively (F=12.11, P<0.01); the serum IgA were (51.69±10.10), (42.40 ± 8.35), (32.11±4.22), (37.12±4.90), (41.45±8.89) µg/ml, respectively (F=8.25, P<0.01); the PFC were (29.2±14.6), (28.0±20.0), (34.8±30.9), (33.2±25.1), (4.8±5.3) per 10(6) splenocyte, respectively (F=3.33, P<0.05); the HC50 were 82.3±6.5, 79.7±4.6, 75.8±4.1, 74.9±3.6, 70.8±2.1, respectively (F=9.99, P<0.01);the LPS-induced splenocyte proliferation were 0.21±0.10, 0.21±0.14, 0.26±0.12, 0.25±0.14, 0.07±0.06, respectively (F=4.18, P<0.05). CONCLUSION: The genetically modified drought-resistant wheat T349 was substantially equivalent to parental wheat in the effects on immune organs and immunologic functions of mice, and it didn't show immunotoxicity.

Assessment on dietary melamine exposure from tainted infant formula.

OBJECTIVE: To estimate the dietary melamine exposure in Chinese infants and young children from the consumption of melamine adulterated Sanlu infant formula. METHODS: Four age groups of infants and young children (3, 6, 12, and 24 months) were chosen as the assessed subjects and the maximum amount of infant formula consumption was estimated based on the recommended usage level in the package insert of Sanlu infant formula and other brands. Melamine was analyzed in 111 Sanlu infant formula samples collected from the markets in Beijing and Gansu province using the LC-MS-MS with a limit of quantification of 0.05 mg/kg. Four levels of melamine concentration were chosen to estimate the dietary intakes, including the mean, median, 90th percentile, and maximum. RESULTS: The infants of 3 months had the highest intake of melamine, and with the increase of the age (month), the intake decreased. Based on the median melamine concentration (1,000 mg/kg) as an example, the melamine intakes for the infants of 3, 6, 12, and 24 months were 23.4, 21.4, 15.0, and 8.6 mg/kg bw/d, respectively. CONCLUSION: Dietary melamine intakes from tainted Sanlu infant formula significantly exceeded the TDI level (0.2 mg/kg bw/d) recommended by the WHO Expert Meeting in 2008. However, the present assessment has some limitations including the poor representative samples, the varied melamine concentrations in the adulterated Sanlu infant formula, and other brand infant formula possibly consumed by these infants.