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重组HSP65-6P277乳酸乳球菌疫苗对链脲佐菌素诱导的1型糖尿病小鼠的降糖作用

Hypoglycemic effect of Lactococcus lactis vaccine containing HSP65-6P277 on streptozotocin-induced type 1 diabetic mice

  • 摘要: 探讨表达HSP65-6P277蛋白的乳酸乳球菌活载体疫苗对链脲佐菌素(STZ)诱导的1型糖尿病小鼠的降糖作用及可能的作用机制。采用多次小剂量腹腔注射STZ建立1型糖尿病模型。将诱导型表达菌株Lactococcus lactis NZ9000 pCYT∶HSP65-6P277和组成型表达菌株L.lactis NZ9000 pHJ∶HSP65-6P277及无关蛋白对照菌株L.lactis NZ9000 pCYT∶Nuc灌胃1型糖尿病小鼠(2×109CFU,200 μL),每天灌胃1次,连续7 d,之后每周灌胃1次,持续16周。每月从小鼠眼眶静脉丛取血1次,血糖检测仪检测STZ造模小鼠血糖水平并称体重。4个月后将小鼠处死,取小鼠脾脏做脾细胞增殖实验,采用ELISA试剂盒分别检测脾细胞上清液中的IL-10和IFN-γ细胞因子水平以及血清IgG抗体水平。结果显示,与对照组相比,pCYT∶HSP65-6P277组和pHJ∶HSP65-6P277组可以一定程度上降低STZ造模小鼠血糖水平(P<;0.05),并能维持其正常体重稳定,降低脾细胞针对HSP65和P277的增殖(P<;0.05),脾细胞上清液中IFN-γ细胞因子水平明显降低(P<;0.05),血清IgG抗体水平无明显差异(P >;0.05)。

     

    Abstract: To study the hypoglycemic effect and mechanisms of vaccine HSP65-6P277 protein on type 1 diabetic mice induced by streptozotocin(STZ), Lactococcus lactis live vector was used to express the vaccine protein. The mouse model of type 1 diabetes mellitus were established by intraperitoneal injections of multiple low dose STZ(MLD-STZ)and divided into three groups. The inducible expression strain L. lactis NZ9000 pCYT ∶HSP65-6P277, constitutive expression strain L. lactis NZ9000 pHJ ∶HSP65-6P277 and control strains L. lactis NZ9000 pCYT ∶Nuc were respectively immunized to diabetic mice orally once daily(2×109 CFU, 200 μL)in the first week and once every week in the following weeks lasting for 16 weeks. Fasting blood glucose levels were measured once a month on blood samples taken from orbital venous plexus. Four months later, the mice were sacrificed. Spleen cell proliferation experiment was performed. IL-10 and IFN-γ cytokine levels of spleen cells and serum IgG levels were assayed using ELISA kits. The results showed that pCYT ∶HSP65-6P277 group and pHJ ∶HSP65-6P277 group have low blood glucose(P < 0. 05), and maintain normal body weight, compared with control group(pCYT ∶Nuc). On the other hand, cytokine IFN-γ levels were significantly lower(P < 0. 05)in spleen cells supernatant and spleen cell proliferation was reduced against HSP65 and P277(P< 0. 05), but serum IgG levels were not significantly different(P> 0. 05).

     

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