Correlation analysis and benchmark dose study on bone metabolic biochemical index of low doses of exposed hydrogen fluoride workers / 中华劳动卫生职业病杂志

Objective: To analyze correlation of occupational hydrogen fluoride exposure to low doses of bone metabolism index through occupational epidemiological investigation and benchmark dose calculation. Methods: In May 2021, using cluster sampling method, 237 workers exposed to hydrogen fluoride in a company were selected as the contact group, and 83 workers not exposed to hydrogen fluoride in an electronics production company were selected as the control group. The external exposure dose and urinary fluoride concentration, blood and urine biochemical indicators of the workers was measured.The relationship between external dose and internal dose of hydrogen fluoride was analyzed. The external dose, urinary fluoride was used as exposure biomarkers, while serum osteocalcin (BGP), serum alkaline phosphatase (AKP) and urinary hydroxyproline (HYP) were used as effect biomarkers for bone metabolism of hydrogen fluoride exposure. The benchmark dose calculation software (BMDS1.3.2) was used to calculate benchmark dose (BMD) . Results: Urine fluoride concentration in the contact group was correlated with creatinine-adjusted urine fluoride concentration (r=0.69, P=0.001). There was no significant correlation between the external dose of hydrogen fluoride and urine fluoride in the contact group (r=0.03, P=0.132). The concentrations of urine fluoride in the contact group and the control group were (0.81±0.61) and (0.45±0.14) mg/L, respectively, and the difference between the two groups was statistically significant (t=5.01, P=0.025). Using BGP, AKP and HYP as effect indexes, the urinary BMDL-05 values were 1.28, 1.47 and 1.08 mg/L, respectively. Conclusion: Urinary fluoride can sensitively reflect the changes in the effect indexes of biochemical indexes of bone metabolism. BGP and HYP can be used as early sensitive effect indexes of occupational hydrogen fluoride exposure.

Regulation of vascular endothelial growth factor and pigment epithelium-derived factor in rat retinal explant under the retinal acidification / 中华实验眼科杂志

BackgroundHypoxia and hyperglycemia are the common causes of retinal neovascularization.In these states,H+ accumulates because of the elevated glycolysis and failure of retinal circulation,thus the retinas readily acidified. ObjectiveThe present study was to explore whether retinal acidosis independently regulates the production of vascular endothelial growth factor (VEGF) and pigment epithelium-derived factor (PEDF) and whether the regulation is related to oxidative stress.Methods The retinas from 2-week-old male SD rats were cultured with explant method in DMEM modulated by NaHCO3,and culture retinas were randomly divided into pH 7.2,6.8 and 6.5 groups for 24 hours.In addition,after 24 hours of culture as above described,retinas were washed using PBS two times and then followed by again culture in DMEM with pH 7.2 for another 24 hours.Also,antioxidant was added in different pH values of DMEM for culture as above described.The retinal samples were prepared for histopathological examination.The expressions of VEGF and PEDF proteins and their mRNA in retina tissue were detected by Western blot and fluorescence quantitative polymerase chain reaction (PCR) respectively.Results The retina showed the clear structure and morphology in pH 7.2 group and pH 6.8 group,but retinal vacuoles change was seen in pH 6.5 group after culture for 24 hours.No significant difference was seen in the expressing level of VEGF mRNA in retina between normal group and pH 7.2 group( 112％ ±11％ vs 100％ ±7％ ) (P=0.55),but those in pH 6.8 group and pH 6.5 group were significant increased in comparison with pH 7.2 group( 196％ ±43％ vs 100％ ±7％ ;251％ ±29％vs 100％ ±7％ )( P＜0.05 ).The expressing level of PEDF mRNA in retina in normal group was similar to that of pH7.2 group(86％ ±19％ vs 100％ ±33％) (P=0.64),but that in pH 6.5 group was significantly higher than pH 7.2 group( 230％ ±66％ vs 100％ ±33％ ) ( P＜0.05 ).The resemble results were found in the expressions of VEGF and PEDF protein.After pH reversion,the expressing levels of VEGF mRNA were 100％ ±13％,111％ ±9％,113％ ±9％ in pH 7.2 group,pH 6.8 group and pH 6.5 group respectively without significant difference among them (F=2.51,P=0.16).The expressing levels of PEDF mRNA were 100％ ±13％,110％ ±9％,108％ ±11％in different groups ( F =0.98,P =0.43 ).Under the presence of antioxidant,the expressing level of VEGF mRNA in pH 6.5 group increased in comparison with pH 7.2 group and pH 6.8 group ( P ＜ 0.05 ).The expressing levels of PEDF mRNA were significant different among pH 7.2 group( 100±31 )％,pH 6.8 group( 282±45 )％ and pH 6.5 group(480±117)％ (F=20.73,P=0.00). Conclusions VEGF can be induced by retinal acidification alone,which may be regulated by oxidative stress.Under the retinal acidification,antioxidants promote the expression of PEDF,suggesting that oxidative stress inhibits the production of PEDF.