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OBJECTIVE@#To investigate the variations in the expression of voltage-gated sodium (Nav) channel subunits during development of rat cerebellar Purkinje neurons and their correlation with maturation of electrophysiological characteristics of the neurons.@*METHODS@#We observed the changes in the expression levels of NaV1.1, 1.2, 1.3 and 1.6 during the development of Purkinje neurons using immunohistochemistry in neonatal (5-7 days after birth), juvenile (12-14 days), adolescent (21-24 days), and adult (42-60 days) SD rats. Using whole-cell patch-clamp technique, we recorded the spontaneous electrical activity of the neurons in ex vivo brain slices of rats of different ages to analyze the changes of electrophysiological characteristics of these neurons during development.@*RESULTS@#The expression of NaV subunits in rat cerebellar Purkinje neurons showed significant variations during development. NaV1.1 subunit was highly expressed throughout the developmental stages and increased progressively with age (P < 0.05). NaV1.2 expression was not detected in the neurons in any of the developmental stages (P > 0.05). The expression level of NaV1.3 decreased with development and became undetectable after adolescence (P < 0.05). NaV1.6 expression was not detected during infancy, but increased with further development (P < 0.05). NaV1.1 and NaV1.3 were mainly expressed in the early stages of development. With the maturation of the rats, NaV1.3 expression disappeared and NaV1.6 expression increased in the neurons. NaV1.1 and NaV1.6 were mainly expressed after adolescence. The total NaV protein level increased gradually with development (P < 0.05) and tended to stabilize after adolescence. The spontaneous frequency and excitability of the Purkinje neurons increased gradually with development and reached the mature levels in adolescence. The developmental expression of NaV subunits was positively correlated with discharge frequency (r=0.9942, P < 0.05) and negatively correlated with the excitatory threshold of the neurons (r=0.9891, P < 0.05).@*CONCLUSION@#The changes in the expression levels of NaV subunits are correlated with the maturation of high frequency electrophysiological properties of the neurons, suggesting thatmature NaV subunit expressions is the basis of maturation of electrophysiological characteristics of the neurons.
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Rats , Animals , Purkinje Cells/physiology , Rats, Sprague-Dawley , Neurons , Brain , Sodium/metabolismABSTRACT
Objective:To analyse the quality control assessment results of arsenic testing laboratories of national endemic disease prevention and control institutions from 2006 to 2020, so as to further strengthen the quality control of arsenic determination in laboratories of national endemic disease prevention and control institutions, and to ensure the accuracy and reliability of national endemic arsenic poisoning monitoring data.Methods:The water arsenic and urinary arsenic test results of arsenic quality control laboratories from 2006 to 2020 were collected and evaluated by Z-ratio scoring method(│Z│≤2 was qualified, 2 < │Z│ < 3 was basically qualified, │Z│≥3 was unqualified), and the qualification rates of water arsenic and urinary arsenic in different years and different provinces were calculated.Results:From 2006 to 2020, the number of laboratories participating in water arsenic quality control in 14 provinces has increased from 25 to 167, and the number of laboratories participating in urinary arsenic quality control increased from 22 to 90. The standard deviation of laboratory assessment samples was relatively stable, all < 0.05 mg/L. The quality control assessment results from 2006 to 2020 were calculated according to │Z│ < 3, the qualified rate of water arsenic ranged from 64.0% to 100.0%, and that in urine was 54.5% to 100.0%. The quality control assessment results from 2009 to 2020 were calculated according to │Z│≤2, the qualified rate of water arsenic was 84.6% - 100.0%, and that in urine was 83.6% - 100.0%. Among the 13 water arsenic assessment results from 2009 to 2020, according to │Z│≤2, provincial laboratories reported all qualified years for 8 times, prefecture, city and county-level laboratories reported all qualified years for 2 times; there were 8 provinces with all qualified laboratories at province level and 3 provinces with all qualified laboratories at prefecture, city and county-level. Among the 13 assessment results of urinary arsenic from 2009 to 2020, according to │Z│≤2, the provincial laboratories reported all qualified years for 6 times, and the prefecture, city and county-level laboratories all qualified for 1 times; there were 6 provinces in which all provincial laboratories were qualified, and there were 6 provinces in which all prefecture, city and county-level laboratories were qualified.Conclusions:The quality control work of laboratories is improving day by day, but there are still some problems in individual links. Laboratories at all levels should continue to strengthen the construction of laboratories and the training of relevant personnel, further improve the theoretical and technical level of inspectors, and continuously improve the detection quality, to make the analysis data more reliable and comparable, so as to ensure the quality of arsenic poisoning prevention and monitoring work.
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Objective:To establish a method for preparing urine arsenic quality control samples and verify its uniformity and stability.Methods:Urine samples of healthy adults were collected, concentrated and then freeze-dried using a freeze dryer. The freeze-dried samples were subjected to atomic fluorescence spectrophotometry to determine the arsenic content. The method was verified from the uniformity, stability, determination of different detection methods, and the fixed value of urine arsenic content.Results:The linear correlation coefficient of the standard curve of the method was 0.999 7. The variation coefficients of arsenic content after freeze-dried of urine samples were all < 5%. The uniformity test results showed that there was no statistically significant difference in the arsenic content between bottles of low and high concentration samples ( t = 1.09, 1.53, P > 0.05), and the sample uniformity was good. The stability test results show that the decline rate of the freeze-dried samples of high and low concentrations stored ≤360 days was less than 10%, and the stability was good at room temperature. Atomic fluorescence spectrophotometry and inductively coupled plasma mass spectrometry(ICP-MS) were used for the arsenic content determination of high and low concentration samples, and there was no significant difference between the two methods ( P > 0.05). The results of determination of arsenic content in urine of 14 provinces and 86 cities and counties showed that the low concentration was (0.028 ± 0.002) mg/L and the high concentration was (0.113 ± 0.008) mg/L. Conclusion:The uniformity and stability of the freeze-dried urine arsenic quality control samples can meet the external quality control requirements of the laboratory in endemic disease prevention and monitoring.
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Objective:To investigate the effects of combined exposure of arsenic and high-fat diet (HFD) on serum adiponectin in mice.Methods:According to the 2 × 3 factorial design, a total of 90 male C57BL/6 mice were randomly divided into 6 groups using random number table method based on body weight (16-22 g): standard diet (STD) control group, STD+ 5 mg/L arsenic group, STD+ 50 mg/L arsenic group, HFD control group, HFD+ 5 mg/L arsenic group and HFD+ 50 mg/L arsenic group. There were 15 mice in each group, and sodium arsenite (NaAsO 2) was added to the drinking water. Mice were accessed freely to water and fed ad libitum. After 17 weeks, urine samples, fasting blood samples and adipose tissue were collected. Urinary arsenic was determined by atomic fluorescence. Blood glucose meter was used to measure blood glucose. Levels of blood lipid contents, including serum triglyceride (TG), total cholesterol (TC), and high density lipoprotein cholesterol (HDL)-c, were examined by kit enzymatic method. Levels of insulin, total adiponectin and high molecular weight (HMW) adiponectin were examined by enzyme-linked immunosorbent assay. Results:There was no interaction between arsenic exposure and HFD on the effects of blood glucose and blood lipids ( P > 0.05). There was an interaction between these two factors on serum insulin and total adiponectin ( P < 0.05). HFD can significantly increase blood glucose, serum TC levels ( P < 0.05), but not TG and HDL-c in mice ( P > 0.05). The levels of TG and HDL-c in STD+ 50 mg/L arsenic group were significantly decreased as compared to those of STD control group (mmol/L: 0.72 ± 0.14 vs 0.88 ± 0.24, 0.67 ± 0.03 vs 0.80 ± 0.16, P < 0.05). Compared with STD control group, there was no significant difference in serum insulin level in HFD control group and STD+ 5 or 50 mg/L arsenic groups ( P > 0.05), but insulin levels in HFD+ 5 or 50 mg/L arsenic groups were significantly decreased (mU/L: 14.71 ± 4.16 vs 11.42 ± 0.78, 11.52 ± 1.53, P < 0.05). Compared with STD control group, serum total adiponectin, HMW adiponectin levels, and the ratio of HMW adiponectin to total adiponectin were significantly reduced in HFD control group and STD+ 5 or 50 mg/L arsenic groups ( P < 0.05). In HFD+ 5 mg/L arsenic group, the above indexes of adiponectin were significantly higher than those of the HFD control group ( P < 0.05). In STD groups, an inverse relationship was observed between log transformed urinary total arsenic concentrations and serum levels of total adiponectin and HMW partial correlation coefficient ( r=- 0.549,-0.608, P < 0.01). Conclusions:Both arsenic exposure and HFD can alter glucose and lipid metabolism in mice, but their manifestations are different. Arsenic exposure and HFD can synergistically reduce serum insulin levels, and have an antagonism on serum adiponectin.
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Objective To carry out a methodological validation of a new standard method "Determination of Iodine in Serum-As3+-Ce4+ Catalytic Spectrophotometry".Methods In accordance with the requirements of "Guide for Establishing Occupational Health Standards-Part 5:Determination Methods of Chemicals in Biological Materials (GB/T 210.5-2008)",the methodological validation was tested in 3 standard development and 3 verification laboratories,calculated the linear relation and range of standard curve and the lowest linmit of detection,precision,accuracy and anti-interference ability,sample stability of sample determination.Results The linear range of iodine mass concentration of the standard curve was 0 to 300 μg/L in 6 laboratories.The linear correlation coefficients of the standard curve obtained from each laboratory were 0.999 1 to 1.000 0.The detection limits of serum iodine were 1.8 to 6.9 μg/L (the.sample amount was 0.10 ml) in 5 laboratories.Precision:15 different serum samples from 5 laboratories with a total iodine concentration range of 48.8 to 273.2 μg/L were repeatedly tested for six times,the relative standard deviations (RSD) were 0.7％ to 3.8％ (the average was 1.7％).Accuracy:a total recovery of samples with iodine concentrations ranging from 26.3 to 253.3 μg/L were performed in 5 laboratories,the recoveries were 96.2％ to 105.2％ (the average was 99.8％).One laboratory carried out the standard method and the inductively coupled plasma mass spectrometry (ICP-MS) method for serum iodine determination.The recovery rates of the two methods were 96.4％ ～ 107.8％,which met the measurement requirements.Anti-interference:15 kinds of chemical reagents were added for interference test in 3 laboratories,and the results showed no deviation,indicating that the standard method had strong anti-interference.Stability:The samples could be stored for 7 days at room temperature,for 2 months at 4 ℃,and for 3 months after freezing when the assay results were not affected.Reaction temperature and time:the appropriate pairing budget for temperature and time was consistent with the standard method.Conclusion The verification of the standard method for serum iodine determination further proves that the standard method has the advantages of simple reagents preparation,wide linear range,better correlation coefficient,lower detection limit,higher precision and accuracy,stronger antiinterference ability,convenient batch testing,and wide applicability.
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Objective To identify the morphology of arsenic in drinking water,by detecting arsenic in the drinking water within the endemic areas so as to determine the causes of arsenic through different forms of arsenic exposure.Methods The arsenic poisoning area and the high arsenic arsenic area in Taonan City and Tongyu County of Jilin Province were selected as the survey sites.The drinking water samples were collected,and the arsenic content and different arsenic species in the water samples were measured and analyze the relationship between well depth and water arsenic content.Resets A total of 161 arsenic water samples were tested,mainly in the form of inorganic arsenic;As5+ concentration was 0.004 to 0.226 mg/L,the median was 0.053 mg/L;the As3+ concentration was 0.004 to 0.309 mg/L,the median was 0.057 mg/L.Total arsenic content was in the range of 0.009 to 0.509 mg/L,the median was 0.100 mg/L.Monomethylated arsenic (MMA) was detected in 1 water sample with the content of 0.005 mg/L,dimethyl arsine (DMA) was detected in 1 water sample with the content of 0.014 mg/L.Totally 101 wells were surveyed with the depth of 13 to 75 meters.Totally 94 water samples had the water arsenic level of more than 0.05 mg/L,and most of them were detected in the well with the depth of more than 50 meters,which was accounted for 85.1％ (80/94).Conclusions Arsenic mainly exists in the form of inorganic arsenic in drinking water,organic arsenic is only found in water at low concentrations.Excessive water arsenic is mainly distributed in wells deeper.
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Objective To identify the morphology of arsenic in drinking water,by detecting arsenic in the drinking water within the endemic areas so as to determine the causes of arsenic through different forms of arsenic exposure.Methods The arsenic poisoning area and the high arsenic arsenic area in Taonan City and Tongyu County of Jilin Province were selected as the survey sites.The drinking water samples were collected,and the arsenic content and different arsenic species in the water samples were measured and analyze the relationship between well depth and water arsenic content.Resets A total of 161 arsenic water samples were tested,mainly in the form of inorganic arsenic;As5+ concentration was 0.004 to 0.226 mg/L,the median was 0.053 mg/L;the As3+ concentration was 0.004 to 0.309 mg/L,the median was 0.057 mg/L.Total arsenic content was in the range of 0.009 to 0.509 mg/L,the median was 0.100 mg/L.Monomethylated arsenic (MMA) was detected in 1 water sample with the content of 0.005 mg/L,dimethyl arsine (DMA) was detected in 1 water sample with the content of 0.014 mg/L.Totally 101 wells were surveyed with the depth of 13 to 75 meters.Totally 94 water samples had the water arsenic level of more than 0.05 mg/L,and most of them were detected in the well with the depth of more than 50 meters,which was accounted for 85.1％ (80/94).Conclusions Arsenic mainly exists in the form of inorganic arsenic in drinking water,organic arsenic is only found in water at low concentrations.Excessive water arsenic is mainly distributed in wells deeper.