Changes in the levels of DNA methylation in testis and liver of SD rats neonatally exposed to 5-aza-2′-deoxycytidine and cadmium

• Published in: Journal of applied toxicology Vol. 31; no. 5; pp. 484 - 495
• Main Authors: Zhu, Hongyan, Li, Keyong, Liang, Jiren, Zhang, Jie, Wu, Qing
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01.07.2011; Wiley; Wiley Subscription Services, Inc
• Subjects: 5-aza-CdR; Animals; Animals, Newborn; Antimetabolites, Antineoplastic - toxicity; Apoptosis - drug effects; Azacitidine - analogs & derivatives; Azacitidine - toxicity; Base Sequence; Biological and medical sciences; Body Weight - drug effects; c-fos; cadmium; Cadmium Chloride - toxicity; Chemical and industrial products toxicology. Toxic occupational diseases; DNA (Cytosine-5-)-Methyltransferase 1; DNA (Cytosine-5-)-Methyltransferases - antagonists & inhibitors; DNA Methylation - drug effects; Drug Therapy, Combination; Enzyme Inhibitors - toxicity; Female; Liver - drug effects; Liver - metabolism; Male; Medical sciences; Metals and various inorganic compounds; Molecular Sequence Data; neonatal exposure; Organ Size - drug effects; p53; Promoter Regions, Genetic; Rats; Rats, Sprague-Dawley; Sperm Count; testis; Testis - drug effects; Testis - metabolism; Testis - pathology; Toxicology; Tumor Suppressor Protein p53; Antineoplastic agent; Neonatal; 5-aza-CdR; Rat; Liver; Decitabine; testis; Testicle; p53; Azanucleoside; TP53 Gene; Nucleoside analog; Pyrimidine nucleoside; Protooncogene; Tumor suppressor gene; Cadmium; Digestive system; fos Gene; Rodentia; c-fos; Transition metal; Exposure; Male genital system; Heavy metal; neonatal exposure; Vertebrata; Mammalia; Animal; DNA; C-Onc gene; Methylation
• ISSN: 0260-437X; 1099-1263; 1099-1263
• DOI: 10.1002/jat.1673

ABSTRACT To investigate the changes in the levels of DNA methylation in the testis during development after neonatal transient exposure to DNA methyltransferase (DNMT) inhibitors, we orally administered Sprague–Dawley (SD) rats with 5‐aza‐2′‐deoxycytidine (5‐aza‐CdR; 0.025 or 0.25 mg kg−1) or cadmium (Cd; 1, 2 or 4 mg kg−1) daily from days 3–7 postpartum (pp). Sperm numbers decreased at day 70 pp in all exposure groups. We then used a PCR‐based assay, combined bisulfite restriction analysis (COBRA) and pyrosequencing to determine the degrees of DNA methylation. Both 5‐aza‐CdR and Cd reduced DNMT activity in vivo after 5 days' exposure at day 8 pp but not at day 70 pp. In contrast, the DNA methylation level of LINE‐1 was not changed in the testis, either at day 8 pp or at day 70 pp. We observed increased apoptosis and an increase in the p53 mRNA level, accompanied by a decreased DNA methylation level in the p53 gene promoter region, at day 8 pp in testis for the 5‐aza‐CdR–exposed groups but not in the Cd‐exposed group. The Cd‐exposed group exhibited a degradation of seminiferous tubules and inhibition of a stepwise change in methylation in the coding region of c‐fos in testis at day 70 pp. Because we observed toxic phenotype development accompanied by aberrant DNA methylation, DNA methylation may play a role in chemical induced testis damage, with different DNMT inhibitors affecting DNA methylation levels in gene‐ or stage‐specific manner. Copyright © 2011 John Wiley & Sons, Ltd. To investigate the changes in the levels of DNA methylation in the testis during development after neonatal transient exposure to DNA methyltransferase (DNMT) inhibitors, we orally administered Sprague ‐Dawley (SD) rats with 5‐aza‐2′‐deoxycytidine or cadmium daily from days 3 to 7 postpartum. Sperm numbers, DNMT activity, as well as DNA methylation level in LINE‐1, in the p53 gene promoter region and in the c‐fos coding region were showed in day 8 and day 70 in the present study.