Serum N-telopeptide of TypeⅠCollagen in Rats with Coal-Burning Type Fluorosis

Objectives  To observe the change of serum N-telopeptide of typeⅠcollagen (NTX) in rats with coal-burning type fluorosis, and to explore the role of bone resorption in skeletal fluorosis.

Methods  One hundred and sixty SD rats at 4 weeks after weaning were divided into four groups, including a control group and three fluoride groups. The rats in fluoride groups were fed with corn (at low-medium-and high-dose level) roasted with coal from a fluorosis endemic area. The rats were executed at the 30^th, 90^th and 180^th day of the experiment respectively. The level of NTX in serum was tested by ELISA.

Results  The concentration of fluoride in urine and bone, the incidence of dental fluorosis, and the pathological score of thighbone were higher with longer-term of fluorosis (P less than 0.05).There were no statistic difference for NTX among the four groups at the 30^th and 90^th day of the experiment; but the NTX levels of low-dose group and medium-dose group were higher than that of high-dose and control group at the 180^th day of the experiment.

Conclusions  At the beginning of taking high fluoride diet, the bone resorption was not strengthened. With the increase of dosage and duration of taking fluoride, the bone resorption was promoted.