Genotoxicity and sperm defects induced by 5-FU in male mice and the possible protective role of Pentas lanceolata-iridoids

•5-FU was demonstrated to be a genotoxic agent. It induced significant increase in micronucleated polychromatic erythrocytes, chromosome anomalies (CAs) and also cytotoxic effects in bone marrow cells (somatic cells). It also induced highly significant percentage of CAs in mouse spermatocytes (germ cells) and a dramatic increase in the percentage of morphological sperm defects.•The results clearly indicated that the genotoxicity of 5-FU in germ cells and its effects on sperm morphology are serious and may lead to reproductive toxicity, infertility or heritable defects.•The biosafety of Pentas lanceolata iridoid-rich fraction and its possible protective role in combined treatment with 5-FU are well established in the present work. 5-Fluorouracil (5-FU) is a widely used antineoplastic drug. In this work, a comprehensive study was performed to detect the extent of chromosomal damage and morphological sperm defects induced by 5-FU in male mice and the possible protective role of the iridoids-rich fraction of Pentas lanceolata leaves (IFPL). Six main groups were examined in micronucleus and chromosomal assays: I- control negative, II- control positive (i.p. treated with single dose of 75 mg/kg 5-FU), III- control plant (orally administrated IFPL, 300 mg/kg, 5 consecutive days), and IV-VI- treated with IFPL (100, 200 and 300 mg/kg, 5 consecutive days) plus 5-FU (i.p. treated at the last day). Samples were taken 24 h post treatment. The study of morphological sperm anomalies, single and repeated treatments were examined and samples were taken after 35 days from the 1st treatment. In bone marrow, 5-FU induced a significant increase in the micro-nucleated polychromatic erythrocytes, chromosome anomalies (CAs) and also cytotoxic effects. A significant percentage of CAs was recorded in spermatocytes after 5-FU treatment reached 22.80 ± 1.32 vs 4.20 ± 0.37 for control (mainly X–Y univalent, 90%). IFPL was recorded to be non-mutagenic in all tests examined. In addition, it alleviated the previous defects in a dose-dependent manner. A significant and dramatic increase in the percentage of morphological sperm defects was recorded after single and repeated treatments with 5-FU reached 13.24 ± 0.24, 30.42 ± 0.32 respectively vs 2.56 ± 0.14 for control. Amorphous head-sperm and sperm with coiled tail were the most pronounced types of abnormalities. Significant protection was detected with the highest tested dose of IFPL. In conclusion: 5-FU demonstrated to be a genotoxic ag