ABSTRACT
OBJECTIVE: To establish the laboratory historical control values for biological indicators in SD rats with 28-day repeated dose oral toxicity tests. METHODS: The body mass, blood routine indexes, serum biochemical indexes, organ mass and organ coefficient of 10 batches of specific pathogen free SD rats in the control group and the control additional group were collected for 28-day repeated dose oral toxicity tests, and the historical control values was established. RESULTS: The body mass of both male and female SD rats increased with the increasing age(all P<0.01). The body mass of male rats was higher than that of female rats each week(all P<0.01). The body mass, blood routine and serum biochemical indexes, organ mass and organ coefficient of SD rats were affected by the age and gender of rats to varying degrees. The effects of age and gender on organ mass and organ coefficient were not consistent. The laboratory historical control values of body mass, blood routine indexes, serum biochemical indexes, organ mass and organ coefficient of SD rats were established according to the age measured in weeks and the gender of rats. CONCLUSION: The laboratory control values of biological indicators of SD rats should be established according to different weekly age and the gender of rats. Organ coefficient is more suitable as an observation index for toxicological safety evaluation compared with organ mass.
ABSTRACT
OBJECTIVE: To explore the effects of aquaporin 4( APQ4) in rat toxic brain edema induced by subacute 1,2-dichloroethane( 1,2-DCE) exposure. METHODS: Thirty-two specific pathogen free healthy adult female SD rats were randomly divided into control( 8 rats),low-dose( 12 rats) and high-dose( 12 rats) groups. The treatment groups were exposed to 1,2-DCE( low-dose: 600 mg / m3; high-dose: 1 800 mg/m3,nose-only) and the control group was exposed to fresh air by dynamic inhalation for 8 hours per day for consecutive 7 days. After exposure,histopathologic changes were examined in the cerebral cortex. Real-time polymerase chain reaction was used to detect the mRNA relative expression of matrix metalloproteinase 2( MMP2),Na-K-Cl cotransporter-1( NKCC1) and AQP4. The Western blotting was used to detect the expression of AQP4 protein in the cerebral cortex. RESULTS: The pathological results showed that the cerebral cortex tissues were loose around the peripheral vessels and the vessels tissue space appeared widen in low-dose exposure group. The pathological change was more serious in high-dose group than low-dose group,with obvious loosen vessels and vacuole. Compared with those of the control group and the low-dose group,the relative expression level of MMP2 mRNA in the high-dose group increased significantly[( 1. 07 ± 0. 41) vs( 1. 56 ± 0. 55),( 1. 21 ± 0. 59) vs( 1. 56 ± 0. 55),P <0. 05],while the the relative expression level of AQP4 mRNA in the high-dose group significantly decreased [( 1. 03 ±0. 25) vs( 0. 81 ± 0. 12),( 1. 00 ± 0. 20) vs( 0. 81 ± 0. 12),P < 0. 05]. The relative expression levels of NKCC1 mRNA in all groups showed no statistical difference [( 1. 03 ± 0. 31) vs( 1. 14 ± 0. 43) vs( 1. 36 ± 0. 50),P > 0. 05]. The relative expression level of AQP4 protein in the high-dose group was lower than that of the control group [( 0. 80 ± 0. 25) vs( 1. 19 ± 0. 42),P < 0. 05]. CONCLUSION: The brain edema induced by subacute inhalation of 1,2-DCE is of mixed types with vasogenic edema as its main symptom. Its pathogenesis is related to the changes of AQP4 expression.
ABSTRACT
OBJECTIVE: To explore the toxicity of 1,2-dichloroethane( 1,2-DCE) and its metabolites on human astrocytes( HAs). METHODS: Different doses of 1,2-DCE( 5. 00,10. 00,25. 00,50. 00 and 100. 00 mmol/L),2-chlorohydrins( 5. 00,25. 00,50. 00,100. 00 and 200. 00 mmol/L),2-chloroacetaldehyde( 1. 00,5. 00,10. 00,20. 00 and 50. 00 mmol / L) and chloroacetic acid( 0. 01,0. 05,0. 10,0. 50 and 1. 00 mmol / L) were used for treating HAs in vitro during their logarithmic phase. After 24 hours of culture,the morphology of HAs was observed by fluorescent inverted phase contrast microscope. The survival rate and the inhibition ratio of HAs were detected by CCK-8 colorimetry to estimate the50% inhibiting concentration in 24 hours( 24 h-IC50). The apoptosis of HAs was tested by double-labeling and flow cytometry using Annexin Ⅴ-fluorescein isothiocyanate and propidium iodide. RESULTS: The morphology of HAs changed in varying degrees after 24 hours exposure to 1,2-DCE,2-chlorohydrins,2-chloroacetaldehyde and chloroacetic acid. The changes included smaller size of cells,pseudopodia tapering,increased intracellular particles and suspension of circular cells and decreased transparency of cells. With the increasing does of 1,2-DCE,2-chlorohydrins,2-chloroacetaldehyde and chloroacetic acid exposure,the survival rates of HAs decreased( P < 0. 01),while its inhibition ratios increased( P <0. 01). They all showed dose-effect relationship. 24 h-IC50 of the above 4 chemicals were 56. 25,235. 00,26. 43 and1. 38 mmol / L,respectively. The 1,2-DCE,2-chlorohydrins and chloroacetic acid could induce the apoptosis of HAs and the apoptosis rate of HAs was positively correlated with the 3 kinds of chemicals( P < 0. 01). CONCLUSION: 1,2-DCE and its metabolites 2-chloroacetaldehyde,2-chlorohydrins and chloroacetic acid can lead to toxic damage and induce the apoptosis of HAs. Chloroacetic acid has the strongest toxicity among the metabolites.