Spermatotoxicity associated with acute and subchronic ethoxyethanol treatment

Investigations of the male reproductive toxicity of ethoxyethanol (ethylene glycol monoethyl ether) have been restricted exclusively to histopathological assessments of the testes. The present study consisted of two experiments designed to document the spermatotoxicity of ethoxyethanol (EE) as reflected in evaluations of ejaculated rat semen. The basic strategy involved the evaluation of individual ejaculates recovered from the genital tract of a female rat prior to exposure of the males to EE. Repeated assessments of the ejaculate were made during the experimental phase according to specified protocols. Adult Long-Evans hooded male rats received 0, 936, 1872 or 2808 mg/kg (PO) of EE for five consecutive days. Semen evaluations were then conducted at weeks 0, 1, 4, 7, 10 and 14 after exposure. Males in the highest two dose groups showed declines in sperm counts by week 4 and were essentially azoospermic by week 7. At this time, males receiving the lowest dose of EE also exhibited decreases in ejaculated sperm counts. An increase in abnormal sperm shapes was also observed. Over the ensuing weeks all males exhibited varying degrees of recovery as reflected by increasing ejaculated sperm counts. In a second experiment, males were treated with 0 or 936 mg/kg of EE daily (5 days/week) for 6 weeks with semen evaluations conducted weekly. By week 5, sperm counts were significantly depressed and there was an increase in the number of abnormal shapes. Sperm motility was depressed by week 6. The temporal trends seen in these experiments suggested a differential sensitivity of the spermatocyte stage to EE toxicity.(ABSTRACT TRUNCATED AT 250 WORDS)