Changes of NO and NOS in lead-treated rat serum and their correlation

Objective To study the changes of serum nitric oxide(NO),nitric oxide synthase(NOS),super oxide dismutase(SOD) and malondialdehyde(MDA) after lead exposure and the relationship between them. Methods NO content in serum(NO 3 -+NO 2 -) was measured by nitric acid reductase,NOS activity in serum was measured by NOS catalyse L Arg producing NO,SOD activity in serum was measured by nitrat coloration and MDA content by TBA method. Results Serum NOS activity in high dose lead exposure groups and control group at the 7th day were 26.03±3.40 and 16.40± 1.29 U/ml respectively,and the former increased significantly( P 0.05).Serum NOS activity decreased significantly after 60 and 90 days exposure( P 0.05).Serum NO content and SOD activity decreased markedly in low and high dose groups after 60 days poisoning( P 0.05).Compared with control group at each dot,MDA content increased significantly in high dose groups except 14 d.There was no correlation between lead in blood and NO,NOS in serum( r =0.217, r =0.119, P 0.05),but there exist negative correlation( r =-0.479, P 0.01) and negative dose effect relationship between lead in blood and SOD in serum,positive correlation( r =0.496, P 0.01) and positive dose effect relationship between lead and MDA in serum( P 0.01).There were positive correlation( r =0.379, P 0.01) and positive dose effect relationship between NO and SOD. Conclusion SOD activity in serum decreased significantly and MDA content increased significantly during chronic lead exposure,and dose effect relationship existed,and there is positive correlation and dose effect relationship between NO and SOD in serum.It was indicated that the effects of lead on NO and NOS were carried out indirectly by SOD.