Comparative study on the immune surveillance injury of blood cerebrospinal fluid barrier induced by exposure to lead acetate and nano-lead sulfide

Abstract

Objective: To investigate the differences in terms of blood cerebrospinal fluid barrier immune surveillance injury by lead acetate and nano-lead sulfide exposure in order to provide basis for the study of their mechanism of nerve injury caused by exposure to lead and nano lead. Methods: In June 2015, forty-five SPF SD male rats were randomly divided into control group, lead acetate group (20 mg/kg) and nano-lead sulfide group (20 mg/kg), with 15 rats in each group. The rats were intragastric five times a week, for nine weeks. The numbers of CD4(+) T lymphocytes in blood and cerebrospinal fluid were detected by flow cytometry. The levels of interleukin-4 (IL-4) and interferon-γ (IFN-γ) in serum and cerebrospinal fluid were detected by ELISA. The expressions and distribution of intercellular cell adhesion molecule-1 (ICAM-1) and CD4(+) T lymphocytes in choroid plexus were detected by laser confocal fluorescence immunoassay. The mRNA expression levels of IL-4, IFN-γ and ICAM-1 in the choroid plexus were detected by real-time PCR. Results: Compared with the control group, the proportion of CD4(+) T lymphocytes in blood of rats in lead acetate group was increased, the proportions of CD4(+) T lymphocytes in cerebrospinal fluid of rats in lead acetate group and nano-lead sulfide group were increased, the contents of IL-4 and IFN-γ in serum of rats in lead acetate group and nano-lead sulfide group were increased, the content of IL-4 in cerebrospinal fluid of rats in lead acetate group and the contents of IL-4 and IFN-γ in cerebrospinal fluid of rats in nano-lead sulfide group were increased, the differences were statistically significant (P<0.05). The fluorescence intensity of ICAM-1 and CD4(+) T lymphocytes in choriochoroid plexus of rats in lead acetate group and nano-lead sulfide group were stronger than those in control group, and the fluorescence intensity of CD4(+) T lymphocytes of rats in nano-lead sulfide group was weaker than that in lead acetate group. Compared with the control group, the mRNA expression levels of ICAM-1, IL-4 and IFN-γ in choriochoroids plexus of rats in lead acetate group and nano-lead sulfide group were increased, and the mRNA expression levels of ICAM-1 and IL-4 in nano-lead sulfide group were higher than those in lead acetate group, while the mRNA expression level of IFN-γ in nano-lead sulfide group was lower than that in lead acetate group (P<0.05) . Conclusion: Exposure to lead and nano-lead sulfide can cause the increase of CD4(+) T lymphocytes, IL-4, IFN-γ and ICAM-1, which may be related to the damage to the immune surveillance of the blood cerebrospinal fluid barrier. And there is a difference in the injury caused by lead and nano-lead sulfide exposure.