CHRONIC EXPOSURE OF PLANT BASED INSECTICIDE PYRETHRIN AFFECTS THE REPRODUCTIVE ORGANS OF MALE WISTAR RATS

Abstract

Insecticides derived from plants, such as pyrethrin, have gained popularity as a safer alternative to synthetic insecticides. Pyrethrin Plant based insecticides are now commonly used in agriculture, households to control pests and thought to be safe. Chronic exposure to pyrethrin insecticides may have adverse effects on the environment and human health. However, its effects especially on male reproductive system especially during chronic exposure has not been studied to any reasonable extent. In this study, we investigated the effects of chronic exposure to plant-derived insecticide pyrethrin on sperm and the male reproductive system of adult Wistar rats. Fifteen adult male Wistar rats used were divided into 3 groups. Group 1 was the control while groups 2 and 3 served as test groups. Group 1 received 2 puffs of distilled water daily, while groups 2 and 3 were exposed to 2 puffs (Low dose) and 3 puffs twice daily (morning and night) for six weeks. Serum samples obtained from the rats were assayed for reproductive hormones (Testosterone, Estradiol, Follicle Stimulating Hormone (FSH) and Luteinizing Hormone (LH)) using Enzyme-Linked Immunosorbent Assay (ELISA). Testes, epididymis, seminal vesicles and the prostate glands were removed for histology, while sperm motility and concentration were determined using sperm from the caudal epididymis and vas deference. Sperm movement kinetics of the rats was determined using Computer Assisted Sperm Analysis (CASA) and histology was determined using Haematoxylin and Eosin (H&E) staining.

There was no significant difference in the relative reproductive organs weight (testis, seminal vesicle, epididymis) among the three groups but there was a significant change (p<0.05) in the prostate glands in group 2 and 3 compared to the control. There were no significant differences in Estrogen, Testosterone, FSH and LH values in the test groups of rats when compared with the control but there was an observable increase. There was no significant difference in the motility and kinetics of the sperm. There was a significant increase in sperm concentration as well as a significant reduction in the numbers of immotile sperm of groups 2 and 3 respectively compared to the control group. Interestingly, tissue damage was observed in the testis, epididymis, seminal vesicles and prostate gland was seen using H&E staining.

Chronic exposure to pyrethrin insecticides did not significantly affect sperm but induced tissue destruction of the male reproductive organs. This may lead to decreased secretions in the testes, epidydimis, seminal vesicles and prostrate glands that may affect male reproductive functions