Broken sperm, cytoplasmic droplets and reduced sperm motility are principal markers of decreased sperm quality due to organophosphorus pesticides in rats.
OBJECTIVE
Recent reports have shown significant associations between organopshophorus pesticide (OP) exposure and decreased sperm motility in workers and laboratory animals. However, the notion that OPs possess spermatotoxicity has yet to be established. The aim of this study was to clarify the effects of OP exposure on detailed sperm toxicity markers, i.e., motility, morphology and sperm adenine nucleotide contents, and the histopathology of the testis and epididymis.


METHODS
Ten-week-old Wistar rats were divided into 4 groups (n=10) and orally administered corn oil, dichlorvos (DDVP; 5, 10 mg/kg) or diazinon (DZN; 3 mg/kg) 6 days a week for 9 wk. Sperm motility and morphology markers were analyzed with a computer-assisted sperm analysis (CASA) system.


RESULTS
In addition to a significant decrease in acetylcholinesterase (AChE) activities and a significant increase in urinary OP metabolites, DDVP and DZN significantly reduced sperm motility, but they did not influence sperm adenine nucleotide contents. The OPs also significantly increased the percentage of broken sperm, and DDVP significantly increased the percentage of cytoplasmic droplets. Importantly, both OPs significantly increased cytoplasmic vacuolation and nuclear shrinkage in the epithelial cells of the ductus epididymis, whereas the testes did not show significant histopathological changes.


CONCLUSIONS
The broken sperm and cytoplasmic droplets as well as reduced sperm motility were the relevant spermatotoxicity makers of DDVP and DZN. To our knowledge, this is the first report to suggest that the above-mentioned OP-induced spermatotoxicity is related to histopathological impairment of the caput epididymis.
Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine, Nagoya, Aichi 467-8601, Japan.
Ai
A
Okamura
Michihiro
M
Kamijima
Katsumi
K
Ohtani
Osamu
O
Yamanoshita
Daichi
D
Nakamura
Yuki
Y
Ito
Maiko
M
Miyata
Jun
J
Ueyama
Takayoshi
T
Suzuki
Ryota
R
Imai
Kenji
K
Takagi
Tamie
T
Nakajima
D000818:Animals; D015415:Biomarkers; D001835:Body Weight / Q000187:drug effects; D003593:Cytoplasm / Q000187:drug effects; D003976:Diazinon / Q000737:chemistry / Q000633:toxicity*; D004006:Dichlorvos / Q000737:chemistry / Q000633:toxicity*; D004822:Epididymis / Q000187:drug effects / Q000473:pathology; D008297:Male; D009929:Organ Size / Q000187:drug effects; D010575:Pesticides / Q000633:toxicity*; D051381:Rats; D017208:Rats, Wistar; D013081:Sperm Motility / Q000187:drug effects*; D013094:Spermatozoa / Q000002:abnormalities / Q000187:drug effects*; D013737:Testis / Q000187:drug effects / Q000473:pathology
D015415:Biomarkers; D010575:Pesticides; D004006:Dichlorvos; D003976:Diazinon