ABSTRACT
OBJECTIVE: To study the effect of nano-cerium oxide on the early development of zebrafish embryos. METHODS: The well-developed zebrafish embryos were randomly divided into the control group and the 50, 100, 200, 400 and 800 mg/L dose groups, with 40 embryos in each group. The dose groups were treated with nano-cerium oxide at the corresponding mass concentration for 5 days. The control group received no treatment. The death and malformation of embryos were observed. The heart rate of zebrafish embryos was recorded using confocol microscope. The protein expression of microtubule-associated protein 1 light chain 3(LC3) and cleaved Caspase-3 and were observed by Western blot technology. RESULTS: The death and embryonic malformation rate of zebrafish embryos increased with the increase of doses, showing statistical significance(P<0.01). The heart rate of the 800 mg/L dose group was decreased compared with the control group [(77±8) vs(93±4) beats/min, P<0.01]. There was no statistical significant difference in LC3-Ⅱ protein expression in each groups(P>0.05). The cleaved Caspase-3 protein expression increased in all dose groups compared with the control group(P<0.05). The cleaved Caspase-3 protein expression in the 200 mg/L dose group was higher than that in the 50 mg/L dose group(P<0.05). CONCLUSION: The nano-cerium oxide may induce cell apoptosis, causing toxic effect in early development of zebrafish embryos.
ABSTRACT
Background and purpose:DNMT3B has nearly 40 known splice variants expressed in a tissue-and disease-speciifc manner, but the roles of these splice variants in the cell are still unclear. The aim of this study was to investigate the effects of overexpression of DNA methyltransferase 3B4 (DNMT3B4) gene on proliferation of human embryo kidney 293A cells. Methods:293A cells were transfected with plasmid pCMV-DNMT3B4 or pCMV-2B and then treated with G418 to get the stable cell line. The stable cell lines were determined for proliferation level by MTT method, and for cell cycle distribution by lfow cytometry. The expression of p21 was detected by real-time PCR and Western blot. The methylation status of p21 gene promoter was detected by methylation-speciifc PCR (MS-PCR). Results:The absorbance value in DNMT3B4-1 and DNMT3B4-2 clone were (58.92±3.47)%and (68.82±5.64)%as compared to 293A-vector cells using MTT method. DNMT3B4 overexpression signiifcantly decreased cell proliferation (P<0.05). S phase fraction of 293A-vector cells was (40.44±0.91)%. While in DNMT3B4-1 and DNMT3B4-2 clone cells, the S phase fraction was (35.88±2.00)%and (37.00±1.79)%respectively. Overexpression of DNMT3B4 could significantly decrease S phase fraction (P<0.05). The expression of p21 in DNMT3B4 overexpressed cells was increased, but the methylation status of p21 gene promoter was unchanged.Conclusion:Overexpression of DNMT3B4 can inhibit 293A cell proliferation and can facilitate p21 expression.