Objective To explore the protective effects of N Acetylcysteine (NAC) on exogenous hydrogen peroxide and endogenous superoxide anion induced DNA strand breakage in human spermatozoa by using the single cell gel el...Objective To explore the protective effects of N Acetylcysteine (NAC) on exogenous hydrogen peroxide and endogenous superoxide anion induced DNA strand breakage in human spermatozoa by using the single cell gel electropherosis (SCGE) Methods Sperm cells were exposed to 0.5 mmol/L of H 2O 2 or 5.0 mmol/L of β NADPH with or without 0.1, 0.5, 1.0 mmol/L of NAC. The percentage of sperm comet cells and the comet tail lengths were measured in the treated sperm cells by using SCGE. Results Both percentage of comet sperm nuclei and mean tail length in sperm cells exposed to 0.5 mmol/L hydrogen peroxide with different concentrations of NAC decrease significantly in a dose dependent manner as compared with sperm cells exposed to H 2O 2 without NAC or catalase. Although mean tail length in sperm cells exposed to 5.0 mmol/L of β NADPH with different concentrations of NAC decreases significantly compared with sperm cells exposed to β NADPH without NAC or SOD, there were no significant differences on the percentage of sperm comet cells between sperm cells exposed to 5.0 mmol/L of β NADPH with different concentrations of NAC and sperm cells exposed to 5.0 mmol/L of β NADPH without NAC. Conclusion NAC has a protective effect on exogenous hydrogen peroxide induced DNA damage, while protective effect of NAC against O - 2 induced DNA strand breakage is significant but very weak.展开更多
Three water-soluble β-alanine C 60 adducts with different addition numbers, C 60(NHCH 2CH 2COONa) nH n(n=1,5,9), were synthesized. The products were characterized by FTIR, 1H NMR and elemental analysis. The antioxida...Three water-soluble β-alanine C 60 adducts with different addition numbers, C 60(NHCH 2CH 2COONa) nH n(n=1,5,9), were synthesized. The products were characterized by FTIR, 1H NMR and elemental analysis. The antioxidant activity of these C 60 adducts as the quencher for superoxide anion radical O -· 2 was evaluated by chemiluminescence in the system of pyrogallol-luminol. The results indicate that the three C 60 derivatives are all excellent quencher for superoxide anion radical O -· 2. The concentrations of 50% inhibition are 252, 140, 112 μmol/L respectively. This high efficiency should be attributed to many factors such as the numbers of remaining double bonds, donor effect of amino group and steric effect. However, the above results also suggest the effect of the adducted β-alanine groups is predominated in this system.展开更多
Enzymes are an important tool used for signal amplification in biosensing.However,traditional amplification methods based on enzymes are always dependent on their catalytic activities,so their signals fluctuate with t...Enzymes are an important tool used for signal amplification in biosensing.However,traditional amplification methods based on enzymes are always dependent on their catalytic activities,so their signals fluctuate with the change of micro-environment(e.g.,pH and temperature).In this work,we communicate an activity-independent enzyme-powered(AIEP)amplification strategy for biosensing to improve signal stability and fidelity.To verify this hypothesis,the monitoring of oxidative stress during drug-induced liver injury was carried out.Carboxylesterase(CEs),highly expressed in hepatic tissue,was selected as the amplification tool.A CEs configuration-matching fluorophore(CMF)was designed and screened,and a nanobeacon was fabricated by loading CMF within an O_(2)^(•-)-responsive polymeric micelle.Since the degradation of the nanobeacon was triggered by O_(2)^(•-),CMF was released to bind with CEs,and the fluorescence was lit by CEs-CMF configuration matching but not catalytic reaction.Results demonstrated that the oxidative stress during drug-induced liver injury could be successfully monitored,and the hepatoprotective effects of repair drugs could be evaluated by cell and in vivo imaging.This strategy is flexible for bioactive molecules by altering the responsive unit and generally accessible for pharmacological evaluation.展开更多
基金China Medical Board ( 980 0 1 ) and Natural Science Foundation ofAnhui Province( 99j1 0 0 95)
文摘Objective To explore the protective effects of N Acetylcysteine (NAC) on exogenous hydrogen peroxide and endogenous superoxide anion induced DNA strand breakage in human spermatozoa by using the single cell gel electropherosis (SCGE) Methods Sperm cells were exposed to 0.5 mmol/L of H 2O 2 or 5.0 mmol/L of β NADPH with or without 0.1, 0.5, 1.0 mmol/L of NAC. The percentage of sperm comet cells and the comet tail lengths were measured in the treated sperm cells by using SCGE. Results Both percentage of comet sperm nuclei and mean tail length in sperm cells exposed to 0.5 mmol/L hydrogen peroxide with different concentrations of NAC decrease significantly in a dose dependent manner as compared with sperm cells exposed to H 2O 2 without NAC or catalase. Although mean tail length in sperm cells exposed to 5.0 mmol/L of β NADPH with different concentrations of NAC decreases significantly compared with sperm cells exposed to β NADPH without NAC or SOD, there were no significant differences on the percentage of sperm comet cells between sperm cells exposed to 5.0 mmol/L of β NADPH with different concentrations of NAC and sperm cells exposed to 5.0 mmol/L of β NADPH without NAC. Conclusion NAC has a protective effect on exogenous hydrogen peroxide induced DNA damage, while protective effect of NAC against O - 2 induced DNA strand breakage is significant but very weak.
文摘Three water-soluble β-alanine C 60 adducts with different addition numbers, C 60(NHCH 2CH 2COONa) nH n(n=1,5,9), were synthesized. The products were characterized by FTIR, 1H NMR and elemental analysis. The antioxidant activity of these C 60 adducts as the quencher for superoxide anion radical O -· 2 was evaluated by chemiluminescence in the system of pyrogallol-luminol. The results indicate that the three C 60 derivatives are all excellent quencher for superoxide anion radical O -· 2. The concentrations of 50% inhibition are 252, 140, 112 μmol/L respectively. This high efficiency should be attributed to many factors such as the numbers of remaining double bonds, donor effect of amino group and steric effect. However, the above results also suggest the effect of the adducted β-alanine groups is predominated in this system.
基金supported by National Natural Science Foundation of China(22222402,21735001,21974013,32001782)Changsha Municipal Natural Science Foundation(kq2208216)+1 种基金the Open Fund of State Key Laboratory of Chemo/Biosensing and Chemometrics of Hunan University(2021018)the Scientific Research Fund of the Hunan Provincial Education Department(23B0308).
文摘Enzymes are an important tool used for signal amplification in biosensing.However,traditional amplification methods based on enzymes are always dependent on their catalytic activities,so their signals fluctuate with the change of micro-environment(e.g.,pH and temperature).In this work,we communicate an activity-independent enzyme-powered(AIEP)amplification strategy for biosensing to improve signal stability and fidelity.To verify this hypothesis,the monitoring of oxidative stress during drug-induced liver injury was carried out.Carboxylesterase(CEs),highly expressed in hepatic tissue,was selected as the amplification tool.A CEs configuration-matching fluorophore(CMF)was designed and screened,and a nanobeacon was fabricated by loading CMF within an O_(2)^(•-)-responsive polymeric micelle.Since the degradation of the nanobeacon was triggered by O_(2)^(•-),CMF was released to bind with CEs,and the fluorescence was lit by CEs-CMF configuration matching but not catalytic reaction.Results demonstrated that the oxidative stress during drug-induced liver injury could be successfully monitored,and the hepatoprotective effects of repair drugs could be evaluated by cell and in vivo imaging.This strategy is flexible for bioactive molecules by altering the responsive unit and generally accessible for pharmacological evaluation.
