弓形虫感染对大鼠脑组织神经丝mRNA表达的影响

目的探讨弓形虫感染对大鼠脑组织神经丝（NF）mRNA表达和细胞免疫水平的影响。方法将4周龄雄性SD大鼠随机分成2组：弓形虫感染组（A组）腹腔感染弓形虫速殖子2×10^2／ml悬液2ml；正常对照组（B组）腹腔注射灭菌生理盐水2ml。感染弓形虫速殖子9周后，应用逆转录聚合酶链反应检测大鼠大脑组织中高分子量NF（NF—H）、中分子量NF（NF—M）和低分子量NF（NF—L）mRNA表达水平；流式细胞术检测大鼠外周血CD3^＋、CD4^＋、CD8^＋T淋巴细胞；ELISA测定其血清IFN-γ、TNF-α、IL-4等细胞因子。结果大鼠弓形虫感染9周后，大脑组织NF．LmRNA下降为正常对照组的64％（P〈0．01）；NF—M为96％（P〉0．05）；NF—H为89％（P〈0．05）。感染组大鼠的CD4^＋和CD8^＋T淋巴细胞与正常对照组相比，差异均无统计学意义（P均〉0．05）；感染组大鼠血清中IFN-γ、TNF-α、IL-4等细胞因子的水平均高于正常对照组大鼠水平（P〈0．05）。结论弓形虫感染可导致大鼠脑组织中NF亚单位mRNA表达水平的下降，血清IFN-γ、TNF-α、IL-4水平的升高。

Effect of Toxoplasma gondii infection on levels of neurofilament mRNA and cellular immunity in rats

Objective To investigate the alterations in levels of neurofilament(NF)mBNA and cellular immunity in rats infected with Toxoplasma gondii.Methods Four-week old male SD mrs were randomly divided into two groups with ten animals for each.The subjects in the experimental group were injected with 2×10~7/ml Toxoplasma tachyzoits 2 ml for each(Group A).Meanwhile,each rat in the control group(Group B)was injected with NaCI 2 ml.After 9 weeks,mRNA levels of light molecular NF(NF-L),medium molecular NF(NF-M)and high molecular NF(NF-H) in cerebrum were determined by RT-PCR.The percentages of CD3~+,CD4~+,CD8~+T lymphocytes were examlnea by flow cytometery,and the peripheral blood levels of IFN-γ,TNF-α,IL-4 were analyzed by ELISA.Results The mRNA levels of NF-L in rat cerebrum decreased significantly to 64%(P<0.01),NF-M decreased to 96%(P>0.05),andNF-H declinedto 89%(P<0.05)of the control.No significant changes were found on the levels of CD3~+,CD4~+,CD8~+T lymphocytes(P>0.05).The levels of lFN-γ,TNF-α and IL-4 in the sera of experimental rats were significantly higher than those in the control group(P<0.05).Conclusion Toxoplasma gondii infection is associated with the alterations in mRNA levels of NF in the cerebrum of rats.