Embryolethality of bromofenofos in rats

Area of Science:

• Veterinary Pharmacology
• Developmental Toxicology
• Teratology

Background:

• Organophosphorus compounds are widely used as anthelmintics in veterinary medicine.
• Assessing the developmental toxicity of veterinary drugs is crucial for animal and human safety.
• Bromofenofos is an anthelmintic agent whose effects on pregnancy have not been extensively studied.

Purpose of the Study:

• To evaluate the embryolethal and teratogenic effects of bromofenofos in pregnant rats.
• To determine dose-dependent toxicity and identify specific malformations induced by bromofenofos.

Main Methods:

• Pregnant rats were administered bromofenofos via gastric intubation from day 8 to 15 of gestation at doses of 0, 2.5, 5, 10, and 20 mg/kg.
• Dams were sacrificed on day 21 of gestation, and reproductive parameters (implants, resorptions, live fetuses) were assessed.
• Fetuses were weighed and examined for external, skeletal, and internal malformations using standard teratological methods.

Main Results:

• Bromofenofos exhibited significant embryolethality, with approximately 91% of implants resorbed at the highest dose (20 mg/kg).
• No external malformations were observed, but the incidence of skeletal malformations (bipartite vertebral centra, wavy ribs) and internal malformations (anophthalmia, hydronephrosis, uterine hypoplasia) was significantly increased at 20 mg/kg.
• Dose-dependent effects were observed, with increasing resorptions and malformations correlating with higher bromofenofos doses.

Conclusions:

• Bromofenofos demonstrates significant embryolethal and teratogenic potential in rats at doses of 20 mg/kg.
• The compound can induce specific skeletal and internal malformations, indicating a risk of developmental toxicity.
• Further research is warranted to understand the mechanisms of toxicity and establish safe dosage limits for bromofenofos during pregnancy.