Study on endoplasmic reticulum stress in bone tissue of fluorosis rats / 中国地方病学杂志

ABSTRACT

Objective To observe endoplagmic reticulum stress in bone tissue of fluomsis rats and further explore the pathogenesis of skeletal fluorosis.Methods 48 Wistar rats were divided into 4 groups according to their body mass.The control and low.calcium group were fed with normal diet(0.79%calcium)and low-calcium diet(0.79%calcium)respectively,and both drank tap water(sodium fluoride concentrations＜1 mg/L).High fluoride and low.calcium plus high-fluoride groups were fed with normal diet(0.79%calcium)and low-calcium diet (0.79%calcium)respectively,and both drank tap water containing sodium fluoride(sodium fluoride concentrations 221 mg/L).During experimental period,rats were measured body mass once a week with a stand diet and water available ad libiturn.The experimental period was 3 months.The biochemical techniques were used to test the indicators of oxidative stress and ALP in seFum of fluorosis rats.The total RNA was extracted from the one side of the femur,and the transcription level of Bip,Xbp1,CHOP and PDI were investigated by reverse transcription polymerase chain reaction(RT-PCR).Results The level of MDA in serum of low-calcium plus high-fluoride group wag higher than that of the control[(14.74±3.11)μmol/L vs(10.15±1.96)μmol/L,P＜0.05];the activity of GPx was ma~edly higher in hish-fluoride group compared with the control[(3.87±0.41)×103 U/L vs(2.85± 0.55)×103 U/L,P＜0.05];the level of uric acid in sel'um was significantly lower both in high-fluoride group and low-calcium plus high-fluoride group compared with the respective control and the low-calcium group[(73.95± 9.52)μmol/L vs(110.43±25.48)μmol/L,(54.32±22.09)μmol/L vs(101.71±17.01)μmol/L,P＜0.05]. The activity of ALP wag obviously higher in low-calcium plus high-fluoride group compared with the control [(24.77±4.57)×103U/L vs (12.91±3.97)×103U/L,P＜0.01)].The mRNA expression of Bip/GAPDH in bone tissue was markedly higher in bone of high-fluoride group and low-calcium plus high-fluoride group compared with the control(1.38±0.24,1.35±0.12 vs 1.14±0.06,P ＜ 0.05). The expression of Xbp1/GAPDH in bone tissue significantly increased in low-calcium plus high-fluoride groups compared with the control and the low-calcium group (1.48±0.20 vs 1.02±0.25,1.07±0.25,P ＜ 0.05 or ＜ 0.01);and CHOP/GAPDH in bone tissue significantly increased in low-calcium plus high-fluoride groups compared with the control(0.84±0.18 vs 0.52±0.07,P ＜ 0.05 ). Conclusions Accelerated osteogenetic action is seen in fluorosis rats,accompanied by oxidative stress and bone endoplasmic reticulum stress,which is likely involved in the pathogenesis of skeletal fluorosis.