抗性淀粉饮食模式下 L -茶氨酸对大鼠肠道免疫功能的调节作用

Effect of L -theanine on intestinal immunity of ratsunder resistant starch feeding

目的:探究抗性淀粉饮食模式下L-茶氨酸对大鼠肠道免疫功能的调节作用。方法:通过对抗性淀粉饮食模式下4周龄SD雄性大鼠进行28 d不同剂量L-茶氨酸[100,300,500 mg/(kg·d)]干预试验,考察抗性淀粉与L-茶氨酸组合营养对大鼠肠道免疫功能的调节作用。结果:在抗性淀粉饮食模式下,中、高剂量组L-茶氨酸能显著增加大鼠体重,提高回肠组织超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)活性,降低回肠丙二醛(MDA)含量;各剂量组均能显著增加回肠白介素-4(IL-4)、白介素-10(IL-10)的表达量,抑制白介素-6(IL-6)、肿瘤坏死因子-α(TNF-α)的表达量,提高免疫球蛋白A(IgA)的表达水平,同时能增加各小肠肠段谷氨酸(Glu)、谷氨酰胺(Gln)含量,提高双歧杆菌属(Bifidobacterium)、普雷沃菌属9(Prevotella_9)、布劳特氏菌属(Blautia)等有益菌丰度,降低肠道有害菌幽门螺杆菌属(Helicobacter)和副萨特氏菌属(Parasutterella)占比(P<0.05),其中,中剂量L-茶氨酸[300 mg/(kg·d)]效果最佳。结论:抗性淀粉饮食模式下L-茶氨酸对大鼠肠道免疫功能具有提高抗氧化能力、平衡促炎/抗炎因子、升高Glu与Gln含量、改善肠道菌群结构等调节作用。

Objective:This study aimed to explore the effect of L-theanine on intestinal immunity of rats under resistant starch feeding.Methods:Different doses of L-theanine[100,300,500 mg/(kg·d)]was performed for 28 days in 4-week-old SD male rats by filling the stomach once daily under resistant starch feeding,in order to investigate the regulation of resistant starch combined with L-theanine on intestinal immunity.Results:The results were shown as follows the medium and high dose groups of L-theanine significantly increased the weight of rats,and improved the activities of ileum SOD,GSH-Px with reducing the content of MDA under resistant starch feeding;Pretreatment with L-theanine at different dosages improved the expressions of IL-4,IL-10,lowered the levels of IL-6,TNF-α,increased the level of IgA in ileum significantly.At the same time,L-theanine could heighten the contents of glutamate and glutamine in each small intestine,and improve the relative abundance of beneficial microorganisms such as Bifidobacterium,Prevotella_9,Blautia reducing the proportion of intestinal harmful microorganisms Helicobacter and Parasutterella(P<0.05).Consequently,the medium dose group of L-theanine[300 mg/(kg·d)]combined with resistant starch had the best effect.Conclusion:Under the resistant starch feeding,L-theanine can enhance intestinal immunity of rats by improving antioxidant capacity,balancing the levels of pro-inflammatory and anti-inflammatory factors and raisng the contents of glutamate and glutamine.In addition,it can also ameliorate the structure of intestinal bacteria to affect intestinal immunity.