益生菌对感染小鼠早期IFN-γIL-4的影响

目的研究口服益生菌对鼠伤寒沙门菌（STM）感染小鼠Th细胞因子的影响，以探讨益生菌抗沙门菌感染的免疫学机制。方法将95只Balb／c小鼠分为4组，分别为益生菌组（P）、益生菌对照组（Pc）、正常感染组（I）和对照组（C）。P组口服益生菌，I组口服生理盐水，均予等剂量STM口服感染，Pc组接种益生菌但不感染STM，C组不作任何处理。各组动物在11个不同时点处死，观察小肠、肝脏、脾脏病理改变，ELISA测量血清IFN-γ、IL-4表达。结果益生菌组器官组织的病理改变轻微，IFN-γ较正常感染组明显增加（Xp-1=66．52，P=0．001），且其表达在感染最初的1h和后期的72h分别出现两个高峰；IL-4明显降低（Xp-1=-29．02，P〈0．001），且较稳定。IFN-γ／IL4比值扩大（Xp-1=2．64，P〈0．001）。结论口服益生菌使小鼠保持有利于抗STM感染的Th1型反应，减轻了STM对机体的免疫损伤。

Effects of probiotics on interfereon-gamma and interleukin-4 during the early stage of infection in mice

Objective To explore the effects of probiotics on the cytokine Th in Salmonella typhimurium （ STM ） - infected mice and discuss the immunological mechanism of the anti-STM infection role of probiotics. Methods 95 Balb/c mice were divided into probioties （P） group, problotics control （Pc） group, infection （I） group and control （C） group, respectively. The mice in group P were given orally probiotics, while the mice in group I were given orally saline; both groups were infected orally with S. thphimurium by equivalent dose. Mice in group Pc were o- rally given probiotics but not infected with STM. Mice in control group were untreated. All mice were sacrificed at a series of time points to observe pathological changes of spleen, liver and small intestine under a microscope. Serum intcrferon-γ （IFN-γ） and interleukin-4 （IL-4） were detected with ELISA. Results In probiotics group, the expression of IFN-γ was significantly higher than in infection group （Xp-1 = 66.52, P = 0.001 ） ; Two distinct expression peaks of IFN-γ appeared at 1 h and 72 h after inoculation respectively; Pathological lesion of mice was mild; The expression of IL-4 was distinctly lower with significantly difference than in infection group （Xp-1 =- 29.02, P 〈0.001 ） ; The ratio of IFN-γ/IL-4 was increased （Xp-1=2.64, P 〈0. 001 ）. The values of IFN-γ and IL-4 of probiotics control group and control group at all time points were not detectable. Conclusion Probiotics induced the expression level of serum IFN-γ, and decreased the expression level of serum IL-γ responding to STM infection in mice. Probiotics can promote immunological response against invaded pathogens and maintain suitable immunological response of organis.