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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.
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Objective To observe the effects of different levels of sodium arsenite ( NaAsO2) on mRNA expression of pigment epithelium-derived factor (PEDF) and apoptosis-related factors in PC12 cells ( rat neuron properties pheochromocytoma). Methods PC12 cells were treated with different levels of NaAsO2 [0 (control group), 2, 5, 10 μmol/L] for 24 hours. The mRNA expression of PEDF and apoptosis-related factors (Bax, Bcl-2) were detected by real-time quantitative PCR. Results There were significant differences in the mRNA expressions of PEDF between the 4 groups (F=102.28, P 0.05); there were significant differences in the mRNA expressions of Bcl-2 between the 4 groups (F=19.87, P<0.05), the mRNA expressions of Bcl-2 in the group of 2, 5, 10 μmol/L (0.65 ± 0.03, 0.49 ± 0.04, 0.57 ± 0.09) were lower than that of control group (0.95 ± 0.11, all P<0.05);there were significant differences in the mRNA expressions of Bax/Bcl-2 between the 4 groups (F=8.352, P<0.05), the mRNA expressions of in the group of 5, 10μmol/L (1.80 ± 0.72, 1.82 ± 0.36) were higher than that of control group (1.02 ± 0.24, all P<0.05). Conclusion NaAsO2 may increase the expression of apoptosis-related factorsBax/Bcl-2 mRNA by decreasing the expression of PEDF mRNA in PC12 cells, leading to apoptosis in PC12 cells.
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Objective To observe the changes of the totle nitric oxide synthase (NOS) activity in brain tissue,the metabolism of arsenic speciations in urine and the totle contents in blood,brain after rats drinking water containing different doses of arsenic.Methods Forty SD rats were divided into 4 groups according to random number table,10 rats in each group:control group,5 mg/L NaAsO2 group,10 mg/L NaAsO2 group and 50 mg/L NaAsO2 group.The animals were allowed free access to water and food.Body mass was weighted once a week.Expose to arsenic was continued for three months,then the animals were put to death and their blood,urine and brain tissues were collected.Determination of four kinds of speciations of arsenic (3 valence inorganic arsenic,iAs3+;5 valence inorganic arsenic,iAs5+;monomethylated arsenic,MMA;dimethylated arsenic,DMA) in urine was carried out by high performance liquid chromatography-hydride atomic fluorescence spectrometry.Total arsenic concentration in blood and brain tissue was detected by Atomic Fluorescence Spectrometry.The activity of total NOS in blood and brain tissue was detected using the spectrophotometer method.Results ①Weight:at the 5th-12th week after arsenic exposure,compared with the weight of control group [(420.93 ± 21.13),(441.52 ± 28.85),(462.45 ± 30.57),(470.16 ± 31.17),(484.92 ± 32.93),(483.79 ± 29.63),(482.02 ± 29.14),(483.89 ± 29.31) g],weight of rats in 50 mg/L NaAsO2 group [(391.66 ± 32.88),(410.17 ± 33.47),(426.96 ± 33.49),(427.15 ± 32.20),(441.78 ± 33.69),(438.27 ± 33.05),(440.98 ± 33.33),(441.46 ± 32.45) g] was significantly lighter (all P ＜ 0.05).② Urine arsenic:the medians of iAs3+ content (0.00,57.30,236.33,857.80 μg/L) were compared between control group,5,10 and 50 mg/L NaAsO2 groups,the differences were statistically significant (x2 =31.982,P ＜ 0.01);the medians of iAs5+ content (0.00,0.00,80.75,162.90 μg/L) were compared between control group,5,10 and 50 mg/L NaAsO2 groups,the differences were statistically significant (x2 =24.206,P ＜ 0.01);the medians of DMA content (12.83,1 711.13,l0 386.20,37 038.90 μg/L) were compared between control group,5,10 and 50 mg/L NaAsO2 groups,the differences were statistically significant (x2 =34.338,P ＜ 0.01).③Blood arsenic:total arsenic content in serum of rats [(5.04 ± 1.57),(25.40 ± 7.33),(32.28 ± 7.75),(56.11 ± 19.87) mg/L] was compared between control group,5,10 and 50 mg/L NaAsO2 groups,the differences were statistically significant (F =27.78,P ＜ 0.05).④Brain arsenic:total arsenic content in brain tissue of 5,10 and 50 mg/L NaAsO2 groups [(0.57 ± 0.20),(1.56 ± 0.52),(3.63 ± 0.48) μg/g] was respectively compared with that of control group [(0.11 ± 0.06) μg/g],the differences were statistically significant (all P ＜ 0.05).⑤NOS activity:compared with control group [(27.69 ± 5.56) kU/L],total NOS activity [(33.63 ± 2.26),(34.19 ± 2.55) kU/L] in serum of rats in 10 mg/L NaAsO2 group and 50 mg/L NaAsO2 group increased significantly (all P ＜ 0.05);compared with control group [(1.79 ± 0.79) U/(mg·prot)],total NOS activity [(2.63 ± 0.60)U/(mg ·prot)] in brain tissue of 50 mg/L NaAsO2 group increased significantly (P ＜ 0.05).Conclusions A high dose of arsenic exposure can increase totle contents of arsenic in blood,brain and the activity of total NOS in rat brain tissue.