Influence of injection timing on severity of cadmium-induced testicular toxicity in mice.
Cadmium (Cd) is one of the endocrine disrupter and is a well-known testicular toxicant. Recently, we reported that Cd-induced mortality was markedly different by injection timing. In this report, we investigated whether severity of testicular toxicity was affected by injection timing of Cd. C57BL/6J mice (male, 7 w) were received single intraperitoneal injection of CdCl(2) (4.5 mg/kg) at zeitgeber time  6 (ZT6) or ZT18; these injection timings showed highest (ZT6) or lowest (ZT18) mortality in our previous study (Miura, 2012). After one week of the injection, several parameters for testicular toxicity such as epididymal sperm motility and numbers of sperm head both in cauda epididymidis and testis were measured. At ZT6 injection group, all parameters examined were significantly reduced compared to the control group. However, very interestingly, no significant changes were observed at ZT18 injection group. We obtained similar results by another experiment in which mice were received single subcutaneous injection of CdCl(2) (4 or 6 mg/kg) followed by measuring the parameters ten days after the injection. This diurnal variation was not contradictory to the result of the lethal toxicity which we showed earlier. Therefore, our results indicate that the testicular toxicity of Cd is also influenced by the injection timing.
Division of Hazard Evaluation and Epidemiology, National Institute of Occupational Safety and Health Japan, Kawasaki, Japan.
Katsumi
K
Ohtani
Yukie
Y
Yanagiba
Atsushige
A
Ashimori
Asuka
A
Takeuchi
Naoko
N
Takada
Masako
M
Togawa
Tatsuya
T
Hasegawa
Masayuki
M
Ikeda
Nobuhiko
N
Miura
D000818:Animals; D002104:Cadmium / Q000008:administration & dosage* / Q000633:toxicity; D052244:Endocrine Disruptors / Q000008:administration & dosage* / Q000633:toxicity; D004822:Epididymis / Q000187:drug effects / Q000473:pathology; D007274:Injections, Intraperitoneal; D007279:Injections, Subcutaneous; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D013076:Sperm Count; D013081:Sperm Motility / Q000187:drug effects; D013733:Testicular Diseases / Q000139:chemically induced* / Q000473:pathology; D013737:Testis / Q000187:drug effects / Q000473:pathology
D052244:Endocrine Disruptors; D002104:Cadmium