ABSTRACT
Objective To detect the osteopontin(OPN)expression in renal tissue of rats with fluorosis and low calcium diet,and study the role of OPN in renal injury of fluorosis.Methods Forty-eight aged 1 month Wistar rats,80-120 g,were randomly divided into 4 groups by 2×2 factorial design(the number of female and male in each group was equal):the control group,high-flluoride group,low-calcium group and low-calcium with high-fluoride group.All rats of the fluorosis groups were fed with feed containing corn exposed to coal-burning from endemic fluorosis areas with high fluoride(100 mg/kg,corn),the other two groups were fed with feed containing coru from nonendemic fluorosis areas(fluoride 5 mg/kg,corn).After 16 weeks,the rats were killed.The change of teeth was examined,and the incidence rate of dental fluorosis was calculated.The expressions of both protein and mRNA of OPN in rat renal tissue were determined by RT-PCR and immunohistochemistry after four-month experimentation.Results The growth of teeth was very well in the control group and the low-calcium group.The two high-fluoride groups showed evident dental fluorosis(100%).The results of immunohistochemistry showed that the OPN protein was localized in renal tubule cytoplasm.The OPN-positive cells from renal tissue were lightly and scatteredly stained in control and low-calcium groups.The OPN-positive cells had deeper color in high-fluoride group and low-calcium with high-fluoride group,widely distributed in the renal tubular epithelial cells.The protein expression of OPN in the two groups exposed to fluoride(168.64±13.21,169.26±8.92)was significantly higher than those of the corresponding control group(145.78±10.26,all P<0.01)and low-calcium group(149.60±16.84,all P<0.01).The mRNA expression of OPN in the two groups exposed to fluoride(1.89±0.37,1.94±0.22)was significantly higher than those of the corresponding control group(1.32±0.26,all P<0.05)and low-calcium group(1.30±0.186,P<0.05),respectively.High fluoride influenced the expression of protein and mRNA of OPN(F=13.821,4.24,all P<0.05).Low calcium did not affect the expression of protein and mRNA of OPN(F=2.164,0.58,all P>0.05).However,high fluoride and low calcium had a cross interaction on the expression of protein and mRNA of OPN(F=6.257,432,all P<0.05).Conclusions Over-dose fluoride enhances the expression of OPN.The higher expression observed in the cases exposed to high fluoride concentration is associated with serious renal injury.OPN may he a potential marker for renal injury in fluorosis.Moreover,over-dose fluoride and low calcium make the renal injury worse,indicating low calcium plays an important part in renal injury by fluoride.
ABSTRACT
Objective To investigate the meaning of PURA gene and its protein in nephridial tissue of the rats with endemic fluorosis of coal burning. Methods Thirty-six SD rats of 80 - 100 g, body weight were randomly divided into control group, low fluorosis group and high fluorosis group according to body weight, 12 in each group, the number of female and male in each group was the same respectively. The control group, Low fluorosis group and high fluorosis group rots were fed with 1.5,25.0,60.0 mg/kg fluoride content in feedstuff, to establish the animal model of fluorosis. Expressions of both mRNA and its protein of PURA gene in rat nephridium tissue, were determined by RT-PCR and immunohistochemistry after four-month experimental period. Results The expressions of PURA mRNA[(2.74± 1.06),(4.29 ± 2.11)] and its protein[ (28 827.91 ± 4801.94),(61 146.96 ± 4997.55)] in low fluorosis group and high fluorosis group was higher than that in the control group[ ( 1.13 ± 0.87), (7131.95 ± 1524.54), all P < 0.05]. And the expressions of PURA mRNA and protein in high fluorosis groups was higher than that in low fluorosis greup(all P < 0.05). Conclusion High fluoride can lead to the high expression of PURA gene mRNA and protein in the rat nephridium tissue exposed to sodium fluoride.