Florfenicol is a broad-spectrum antibiotic that used in different diseases. There is no evidence for teratogenicity effect of florfenicol; the aim of this study was to evaluate the teratogenic effect of florfenicol on skeletal system of rat fetuses. This study was performed on 39 pregnant rats in 5 groups, including first group (control group) and 2-5 groups (test groups) that was received florfenicol at doses 100, 200, 400 and 800 mg/kg, respectively. The drug was administrated at 8th and 10th days of gestation intraperitoneally. The rats were euthanized and fetuses were collected at 20th day of gestation prior to calculation of weight and length. Then, they were stained by alizarin red- alician blue method. The stained skeletal system of the fetuses were eviscerated and cleaned before they investigated by stereomicroscope. Fetus absorption rate in 1-5 groups were 4.09%, 22.64%, 44.68%, 53.58% and 59.32%. Skeletal teratogenicities consist of cleft palate, sternum malformation, reduce limbs ossification of hind limb and fore limb, observed in 4th group (400 mg/kg florfenicol) were 11.53, 11.53 and also 11.53% and in 5th group (800 mg/kg florfenicol) 20.38, 12.50 and 37.50%. It is concluded that, florfenicol produced some tratogenic skeletal disorders including cleft palate, sternum malformation; reduce limbs ossification and fetus absorption doses-depended in rat fetuses.
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