| rat offspring |
Developmental |
The rats were randomly divided into 2 groups, e.g., higher fluoride exposed group (9 rats with 6 female and 3 male), in which the diet was made from corn polluted by fluoride during the corn-drying processes with burning coal containing high level of fluoride in a severe endemic fluorosis area — Bijie County in Guizhou province of China and contained 104.2 mg/kg sodium fluoride (NaF); and control group (9 rats with 6 female and 3 male) fed normal diet containing 6.2 mg/kg NaF.; Eighteen parental SD rats with one month old were purchased from the Experimental Animal Center in Guizhou, China, and ethical permission for these experiments was obtained from the regional ethical committee for animal studies in Guizhou. All animals were housed in stainless-steel cages suspended in stainless-steel racks with the humidity ranged from 30 to 55% and the room temperature remained between 22 and 25 °C, fed with tap water containing low- fluoride (0.5 mg/L) and acclimatized for one week in a housing facility before treatment. Six months after establishing the animal model with chronic fluorosis, the experimental rats and controls with 2:1 proportion of female:male, respectively, were housed in a single cage, respectively. The female animals were allowed to become pregnant by natural mating. After lactation, the offspring rats born from fluorosis rats were fed with the same food containing high fluoride as their parents and the offspring in control fed normal diet. At the day 30 after born, 10 offspring rats in each group were selected for the experiment. |