Objective To explore more accurate method about the time of pregnancy and gestational age of SD rats.Methods 7 to 8-week-old SD rats (18 females,6 males) were selected,the ratios of male to female were 2:1,5:2,1:1 and 4:1.Through vaginal plug observation,vaginal smear method,weight comparison method to verify the exact date of pregnancy in the next morning.Results Vaginal observed at milky vaginal plug sperm could be observed as sickle rat sperm head.Body weight of pregnant rats changed obviously.Three detection methods were used to detect the pregnancy time for 18 females.The positive rate of vaginal plug observation was 5.6％.The positive rate of vaginal smear method was 44.4％.The false negative rate of vaginal smear method was 11.1％.The positive rate of body weight method was 11.1％.The false positive rate was 5.6％.Conclusion The accuracy of vaginal smear is higher than the vaginal plug method and weight comparison method,the vaginal plug method can be used as the premise of the other two methods.Comparison method can be used as supplementary that the other two methods missed.

Objective: To observe the influence of excessive fluoride on the levels of osteocalcin and testosterone in the testis of the male mouse. METHODS: Twenty-four C57BL/6J male mice were equally randomized into a normal control and a fluorosis model group, the former fed on distilled water while the latter on a solution of sodium fluoride (100 mg/L) in distilled water, both for 12 weeks. Then, the level of osteocalcin in the testis tissue was measured with the immunohistochemical streptavidin-peroxidase (SP) method and those of osteocalcin and testosterone in the serum determined by ELISA. RESULTS: After 12 weeks of fluoride intervention, the level of serum osteocalcin was significantly higher in the fluorosis models than in the normal controls (［68.05 ± 5.32］ vs ［47.50 ± 5.73］ pg/mL, F = 11.901, P = 0.008), while that of testosterone markedly lower in the former than the latter group (［8.07 ± 1.35］ vs ［12.94 ± 3.09］ ng/mL, F = 2.313, P = 0.006). The results of immunohistochemical SP showed the expression of osteocalcin in the cell membrane and cytoplasm of the fluorosis models, which was evidently higher than in the normal controls. CONCLUSIONS Twelve-week intake of 100 mg/L fluoride solution can decrease the level of testosterone and increase the expression of osteocalcin in the testis of the male mouse.
Animals ; Fluoride Poisoning ; metabolism ; Fluorides ; toxicity ; Male ; Mice ; Mice, Inbred C57BL ; Osteocalcin ; metabolism ; Random Allocation ; Sodium Fluoride ; toxicity ; Testis ; drug effects ; metabolism