白及多糖对GU模型大鼠胃组织PI3K/Akt的影响

目的:探讨白及多糖对胃溃疡(GU)模型大鼠胃组织磷脂酰肌醇3-激酶(PI3K),蛋白激酶B(Akt) m RNA及蛋白,以及其介导细胞因子白细胞介素-2受体(IL-2R),白细胞介素-4(IL-4)表达水平的影响。方法:将60只SPF级Wistar大鼠随机分为空白组和模型组,模型组大鼠采用乙酸直接烧灼法复制GU模型,将GU模型大鼠按随机数字表法分为模型组、盐酸雷尼替丁组和白及多糖高、中、低剂量组共5组,每组10只。空白组和GU模型组大鼠给予10 m L·kg~(-1)·d~(-1)蒸馏水灌胃,白及多糖高、中、低剂量组分别予0. 5,0. 25,0. 125 g·kg~(-1)·d~(-1)白及多糖灌胃,盐酸雷尼替丁组给予0. 3 g·kg~(-1)·d~(-1)盐酸雷尼替丁灌胃,治疗15 d。采用酶联免疫吸附测定(ELISA)法检测各组大鼠血清一氧化氮(NO)含量及胃组织胃蛋白酶活性及细胞因子IL-2R,IL-4含量,实时荧光定量聚合酶链式反应(Real-time PCR)法检测胃溃疡病灶组织PI3K及Akt m RNA表达水平,蛋白免疫印迹法(Western blot)检测胃溃疡病灶组织PI3K及Akt蛋白表达水平。结果:与空白组比较,胃组织细胞因子IL-2R,IL-4含量及m RNA表达显著升高,PI3K,Akt m RNA及蛋白表达水平显著升高(P 0. 01);与GU模型组比较,白及多糖高、中、低剂量组IL-2R,IL-4含量及m RNA表达均降低,以白及多糖高剂量组降低显著,PI3K,Akt m RNA及蛋白表达水平均降低,以白及多糖高、中剂量组降低显著(P 0. 05,P 0. 01)。结论:白及多糖可通过下调PI3K及Akt m RNA和蛋白表达水平,抑制细胞因子IL-2R及IL-4异常分泌而发挥保护胃黏膜的作用。

Effect of Bletillae Rhizoma Polysaccharide on PI3K/Akt in Gastric Tissue of GU Model Rats

Objective: To investigate the effect of Bletillae Rhizoma polysaccharide on the expressions of phosphatidylinositol 3-kinase (PI3K), protein kinase B (Akt) gene protein and its mediated cytokines interleukin-2 receptor (IL-2R) and interleukin-4 (IL-4) in gastric tissue of rats with gastric ulcer (GU). Method: Sixty SPF Wistar rats were randomly divided into blank group and model group.The GU model was replicated by direct acetic acid cauterization in model group.The GU model rats were randomly divided into five groups:model group, positive control group, and large, medium and small-dose Bletillae Rhizoma polysaccharide groups, with 10 rats in each group.Rats in blank group and GU model group were given 10 mL·kg^-1·d^-1 distilled water by gavage, rats in large, medium and small-dose groups were given 0.5, 0.25, 0.125 g·kg^-1·d^-1 Bletillae Rhizoma polysaccharide by gavage, while rats in positive control group were given 0.3 g·kg^-1·d^-1 ranitidine by gavage for 15 days.Serum nitric oxide (NO) content, pepsinase activity and cytokines IL-2R and IL-4 levels in rats of each group were measured by enzyme-linked immunosorbent assay (ELISA), PI3K and Akt mRNA expressions were detected by Real-time fluorescent quantitative polymerase chain reaction (Real-time PCR), and PI3K and Akt protein expressions were detected by Western blot. Result: Compared with the blank group, the contents and gene expressions of cytokines IL-2R and IL-4 in gastric tissue were significantly increased, and the PI3K and Akt genes and protein expressions were significantly increased, with statistical significance (P<0.01). Compared with GU model group, the content and gene expressions of IL-2R and IL-4 in large, medium and small-dose Bletillae Rhizoma polysaccharide groups were decreased significantly, and the PI3K and Akt gene and protein expressions were decreased significantly in large-dose Bletillae Rhizoma polysaccharide group, while those in large and medium-dose Bletillae Rhizoma polysaccharide groups were decreased significantly (P<0.05, P<0.01). Conclusion: Bletillae Rhizoma polysaccharide can protect gastric mucosa by down-regulating PI3K and Akt gene and protein expressions and inhibiting abnormal secretion of cytokines IL-2R and IL-4.