摘要:
Objective To analyze the changes of endoplasmic reticulum stress (ERS) in the spleen of water-improving fluorosis rat,to explore the mechanism of fluoride-induced immune system damage,and to provide a scientific basis for prevention and control of endemic fluorosis.Methods Forty-eight male Wistar rats of SPF grade were randomly divided into control group and low,medium and high fluoride dose groups according to body mass (120-140 g),12 rats in each group.The sodium fluoride (NaF) content was 0,50,100 and 150 mg/L,respectively.The animals were allowed free access to water and food.After 12 weeks of fluoride exposure,6 rats in each group were selected to isolate the spleen;the remaining rats in each group were changed to drink distilled water containing no NaF,and the spleen was separated after 12 weeks of feeding.The levels of mRNA of glucoseregulated protein (GRP78),spliced X-box binding protein 1 (XBP1-s),activating transcription factor 4 (ATF4),homologous protein (CHOP) and cysteine containing aspartate specific protease 12 (Caspase-12) in spleen were determined by quantitative real-time PCR (qRT-PCR).Results Before the water-improving,the expressions of GRP78 (1.00 ± 0.09,1.69 ± 0.35,1.39 ± 0.29,1.19 ± 0.19),XBP1-s (1.00 ± 0.12,1.40 ± 0.23,1.24 ± 0.26,1.38 ± 0.11),ATF4 (1.00 ± 0.17,1.86 ± 0.56,2.33 ± 0.55,1.95 ± 0.74),CHOP (1.00 ± 0.53,2.84 ± 0.68,3.06 ± 1.29,2.50 ± 0.35) and Caspase-12(1.00 ± 0.12,1.90 ± 0.29,1.56 ± 0.35,1.76 ± 0.23) mRNA in the control group and low,medium and high fluoride dose groups were statistically significant (F =8.45,5.38,6.38,8.21,11.31,P < 0.05).Except for the GRP78 in high fluoride dose group,the above indicators in fluoride groups were higher than the control group (P < 0.05).After the water-improving,the expressions of GRP78 (1.00 ± 0.36,0.75 ± 0.13,0.98 ± 0.41,0.47 ± 0.19),XBP1-s (1.00 ± 0.25,0.70 ± 0.06,0.74 ± 0.17,0.65 ± 0.21),ATF4 (1.00 ± 0.51,0.66 ± 0.09,0.91 ± 0.34,0.81 ± 0.29),CHOP (1.00 ± 0.36,0.92 ± 0.12,0.84 ± 0.16,0.67 ± 0.20) and Caspase-12 (1.00 ± 0.45,0.65 ± 0.11,0.65 ± 0.25,0.51 ± 0.27) mRNA in the control group and low,medium and high fluoride dose groups were not statistically significant (P > 0.05).Before and after the water-improving,the expressions of XBP1-s,ATF4,CHOP and Caspase-12 mRNA were statistically significant in fluoride groups (P < 0.05),and the GRP78 only had a statistically significant difference in the low fluoride dose group (P < 0.05).Conclusions Fluoride exposure causes ERS response in rat spleen,up-regulation of ERS-related gene expression,which is decreased after water-improving,and the ERS response is weakened.The water-improving may contribute to the recovery of fluoride-induced immune function damage.%目的 分析改水后氟暴露大鼠脾脏内质网应激反应(endoplasmic reticulum stress,ERS)水平的变化,探讨氟致免疫系统损伤机制,并为改水降氟防治工作提供科学依据.方法 选取SPF级Wistar雄性大鼠48只,按体质量(120~140 g)采用随机数字表法将其分为对照组和低、中、高氟剂量组,每组12只,各组饮用水中氟化钠(NaF)含量分别为0、50、100、150 mg/L.常规饲料喂养,自由饮水.染氟持续12周,每组选取6只大鼠分离脾脏;剩余6只大鼠改为饮用不含NaF的蒸馏水,继续饲养12周分离脾脏.采用实时荧光定量PCR(qRT-PCR)检测ERS相关基因葡萄糖调节蛋白78(GRP78)、剪切型X盒结合蛋白(XBP1-s)、活化转录因子4(ATF4)、增强子结合蛋白同源蛋白(CHOP)和半胱氨酸天冬氨酸酶12(Caspase-12)的mRNA表达水平.结果 改水前,对照组,低、中、高氟剂量组的GRP78(1.00±0.09、1.69±0.35、1.39±0.29、1.19±0.19)、XBP1-s(1.00±0.12、1.40±0.23、1.24±0.26、1.38±0.11)、ATF4(1.00±0.17、1.86±0.56、2.33±0.55、1.95±0.74)、CHOP(1.00±0.53、2.84±0.68、3.06±1.29、2.50±0.35)和Caspase-12(1.00±0.12、1.90±0.29、1.56±0.35、1.76±0.23)的mRNA表达组间比较,差异有统计学意义(F=8.45、5.38、6.38、8.21、11.31,P均<0.05),除高氟剂量组的GRP78外,其他各染氟组的上述指标均高于对照组(P均<0.05);改水后,对照组,低、中、高氟剂量组GRP78(1.00±0.36、0.75±0.13、0.98±0.41、0.47±0.19)、XBP1-s(1.00±0.25、0.70±0.06、0.74±0.17、0.65±0.21)、ATF4(1.00±0.51、0.66±0.09、0.91±0.34、0.81±0.29)、CHOP(1.00±0.36、0.92±0.12、0.84±0.16、0.67±0.20)和Caspase-12(1.00±0.45、0.65±0.11、0.65±0.25、0.51±0.27)的mRNA表达组间比较,差异无统计学意义(P均> 0.05);低、中、高氟剂量组XBP1-s、ATF4、CHOP、Caspase-12的mRNA表达改水前后比较差异有统计学意义(P均< 0.05),GRP78仅低氟剂量组比较差异有统计学意义(P<0.05).结论 氟暴露可以引起大鼠脾脏的ERS反应,使ERS相关基因表达上调,改水后有所下降,ERS反应减弱;改水措施有助于氟致免疫功能损伤的恢复.