Abstract
Objective Aim of the study is to investigate the expression of syndecan-4 and nuclear factor kB (NF-kB) in the kidney of rat with chronic fluorosis,and to reveal the mechanism of kidney damage resulted from the toxicity of excessive amount of fluoride.
Methods According to body mass and sex,sixty SD rats were randomly divided to three groups according to body mass and fed with different contents of fluoride:control group with normal tap-water (< 0.5 mg/L fluoride),small dosage of fluoride exposure group (adding 10 mg/L fluoride in tap-water) and large dosage of fluoride exposure group (50 mg/L fluoride) for six months.The protein level of syndecan-4 and NF-kB in the kidney was detected by Western blotting and syndecan-4 mRNA level by quantitative real time PCR.
Results As compared to the control group[(100.0 + 8.1)%],the expression of syndecan-4 at protein level in the kidney of rat was significantly increased in the small dosage of fluoride exposure group [(198.5 + 5.6)%, P < 0.05] and large dosage of fluoride exposure group [(209.2 + 13.0)%, P < 0.05]; the protein levels of NF-kB in the small dosage of fluoride exposure group[(284.4 + 11.1)%, P < 0.05] and in the large dosage of fluoride exposure group [(343.2 + 2.9)%, P < 0.05] were significantly increased than that of the control group [(100.0 ± 10.7)%]. The mRNA levels of syndecan-4 in the kidney in the small dosage of fluoride exposure group and large dosage of fluoride exposure group(0.431 + 0.058 and 0.453 ± 0.065, both P < 0.05,respectively) were significantly increased than that of the control(0.128 + 0.026).
Conclusions The increased expression of NF-kB in the kidney is induced by increased expression of syndecan-4, which may be involved in kidney damage of chronic fluorosis.