Abstract
Background: Dimethoate is one of the most organophosphorus pesticide used in all over the world to control insect pests, the extensive use of this insecticide causes a health hazard to animals and humans.
Aim: This study was conducted to evaluate the positive effect of green tea extract on sperm quality and testicular cytoarchitecture in male mice treated with dimethoate and on its reproductive performance.
Methods: The mice were divided into three groups, each group contained nine mice, the first group (control) was given distilled water only, the second group received dimethoate at a dose (0.1 ml dimethoate /100 ml distilled water) while the third group was given dimethoate at a dose (0.1 ml dimethoate/ 100 ml distilled water) and the green tea extract at a dose (100 mg/kg). After 20 days of the treatment, six mice from each group were killed, sperm quality (sperm count, morphology motility) and histopathological lesions of testis were carried out.
Results: The results showed that dimethoate significantly affected sperm quality a decrease in sperm motility and an increase in abnormal sperm morphology) and caused marked alterations in the microstructures of testicular tissues. When treated males were mated with untreated females, a decline in the number of live embryos was found, while the green tea extract revealed an effective role by reducing those negative influences.
Conclusion: This study revealed that dimethoate has detrimental effects on sperm quality, testicular tissues and the embryos while treatment with green tea revealed a positive role in improving those negative influences of dimethoate without it causes any harmful side effects

Key words: Dimethoate, Green tea, Male mice, Histoarchitecture, Fertility