| 6-month drinking water |
Chronic (>90 days) |
Before treatment, the rats were acclimatized for one week and were then randomly divided into three groups: (a) normal control group with less than 0.5 mg NaF/L in their drinking water; (b) a lower F-exposed group with 5 mg NaF (2.26 mg F ion)/L in their drinking water; and (c) a higher F-exposed group with 50 mg NaF (22.6 mg F ion)/L in their drinking water.; Seventy-two young Sprague-Dawley rats (half males and half females, weighting 90-120 g) were purchased from the Experimental Animal Center in Guizhou, China. Ethical permission for these experiments was obtained from the regional ethical committee for animal studies in Guizhou. In the animal housing facility the humidity ranged from 30 to 55% with the temperature between 22 and 25 deg C. Before treatment, the rats were acclimatized for one week…. During the study, four rats per cage (single sex per cage) were housed in stainless-steel cages suspended in stainless-steel racks, and the treated water and food were available ad libitum. At the end of 6 months, the rats were tested for learning and memory and sacrificed for biochemical study of their brain tissue. |