THE CONDITION OF THE REPRODUCTIVE SYSTEM IN MALE WISTAR HANNOVER RATS EXPOSEDTO TYPE II PYRETHROID — BETA-CYFLUTHRIN

Abstract

Background. Type II pyrethroids, particularly beta-cyfluthrin, are insecticides used in agriculture that have toxic effects on non-target organisms. Despite the high biological activity of this cyanogen-containing stereoisomer, its effects on the male reproductive system have not been sufficiently studied compared to cyfluthrin. This highlights the relevance of investigating the reproductive toxicity of beta-cyfluthrin in male Wistar Hannover rats.

Aim. To investigate the state of the reproductive system of male Wistar Hannover rats following exposure to beta-cyfluthrin within a single generation.

Methods. The study was conducted on male Wistar Hannover rats that were orally administered beta-cyfluthrin at doses of 3.0 and 30 mg/kg body weight for 10 weeks (5 times per week). Control males (0 mg/kg body weight) received distilled water with an emulsifier. Gonadal function and fertility were assessed by mating males with intact females (1:2). The status of embryogenesis was analyzed on the 20th day of gestation. Statistical data analysis was performed using Python. The normality of the distribution was tested using the Shapiro-Wilk test. In cases of non-normal data distribution, the Mann-Whitney and Kruskal-Wallis tests were used. Results were considered statistically significant at p ≤ 0.05.

Results. It was established that beta-cyfluthrin exerts a general toxic effect on the test rats, manifested by a decrease in body weight at 3 mg/kg body weight—from the 6th to the 10th week of exposure by 5.06–7.56 % (from the 6th to the 8th weeks p ≤ 0.01, from the 9th to the 10th week p ≤ 0.001) and at 30 mg/kg body weight—from the 3rd to the 10th week of exposure by 7.00–18.03 % (p ≤ 0.0001). At the maximum dose, disturbances in the morphofunctional state of spermatozoa were also observed, specifically: a 33.94 % decrease in progressive motility (p ≤ 0.02) and a 38.74 % decrease in the percentage of medium-progressive spermatozoa (p ≤ 0.001), an increase in the percentage of morphologically abnormal spermatozoa by 19.52 % (p ≤ 0.01) and a decrease in the percentage of normal spermatozoa by 26.84 % (p ≤ 0.01), as well as a decrease in the fertility index by 20 % (p ≤ 0.05). A dose of 3 mg/kg body weight did not cause statistically significant changes in reproductive parameters.

Conclusions. It was established that beta-cyfluthrin at a dose of 30 mg/kg body weight causes pronounced reproductive toxicity, manifested by a decrease in the fertility index of males. It also causes suppression of sperm motility and an increase in the proportion of abnormal sperm forms. At a dose of 3 mg/kg body weight, beta-cyfluthrin does not cause significant disturbances in male reproductive function. Therefore, the 3 mg/kg dose is ineffective based on the reproductive parameters studied.