| Background With the epidemic of human obesity,dietary fats have increasingly become a focal point of biomedical research.Epidemiological studies indicate that high-fat diets(HFDs)have multi-organ pro-inflammatory effects,and cause chronic forms of intestinal inflammation.The incidence and severity of chronic inflammatory diseases in industrialized countries,especially inflammatory bowel disease,are increasing.The majority of patients have recurrent attacks and prolonged unhealed,and quite a few of them require surgical treatment due to complications.Objective This study was designed to explore the Improving effect and underlying mechanism of Saponins from Panax Japonicus(SPJ)on intestinal inflammation.It is expected to provide a theoretical basis for the clinical application and new drug development of Saponins from Panax Japonicus(SPJ)in the prevention and treatment of intestinal inflammation.Methods A total of 32 male SPF level C57 BL / 6 mice were randomly divided into 4groups,namely the normal control group,the high-fat-diet group,HFD + low-dose SPJ(SPJ-L,50 mg/kg),and HFD + high-dose SPJ(SPJ-H,150 mg/kg)groups.0.5% sodium hydroxymethyl cellulose was used to prepare SPJ solutions at 5 mg/m L and 15 mg/m L.Mice in the low-dose and high-dose SPJ group were given 50 mg/kg and 150 mg/kg of SPJ solution,respectively,for intragastric administration.Meanwhile,the mice of high-fat diet group were given with a 5% CMC-Na solution for intragastric administration.The mice in the normal control group were fed with normal feed,while the mice of the high-fat-diet group,HFD +low-dose SPJ group,and HFD + high-dose SPJ group were fed with high-fat feed.Mice in each group were fed continuously for 4 months.Then all the mice were killed under anesthesia.(1)The immunohistochemical method was used to observe the effect of SPJ on the expressions of inflammatory factors,including IL-1β,TNF-α and NF-κB p65,in the jejunum of mice fed with a high-fat diet.(2)Real-time quantitative PCR technique was used to detect the effect of SPJ on the expression of IL-22 m RNA involved in inflammatory in jejunum of mice on a high-fat diet.(3)The immunohistochemical technique was used to observe the effect of SPJ on the expressions of endoplasmic reticulum stress-related proteins,including p-e IF2α,ATF4,ATF6α,GRP78,CHOP,and p-IRE1α,in jejunal epithelial cells of high-fat-diet-fed mice.(4)The method of HE staining was used to observe the morphological changes in jejunal tissue of mice in each group.(5)The triglyceride kit was used to detect the levels of triglyceride in jejunal tissue of all mice.(6)Real-time quantitative PCR technique was used to detect the effect of SPJ on relative expression levels of lipid metabolism genes associated with triacylglycerol(TG)synthesis(DGAT1,DGAT2,GPAT3,Mogat1,Mogat2),FA trafficking(FABP1,FABP2,CD36),Chylomicrons packaging(CD36,and MTP),Cyloplasmic lipolysis(ATGL,HSL,MGL),and lipophagy(LAL),in jejunal epithelial cells of mice fed with a high-fat diet.(7)The immunohistochemical method was used to observe the effect of SPJ on the expression of nuclear transcription factors PPAR-γ in jejunal epithelial cells of mice on a high-fat diet.Results(1)The results of immunohistochemistry showed that compared with the mice of the normal control group,the protein expressions of NF-κB p65,TNF-α,and IL-1β were significantly increased in jejunal tissue of mice on a high-fat diet.The protein expression of NF-κB p65,TNF-α,and IL-1β in jejunal tissue of mice on a high-fat diet were significantly decreased after the administration of low-and high-doses of SPJ.(2)The results of real-time quantitative PCR showed that compared with the normal control group mice,the expression of IL-22 m RNA in the jejunum of mice fed with high-fat diet was increased;compared with the high-fat diet group,the expression of IL-22 m RNA in jejunum of mice was significantly down-regulated after the administration of low-doses and high-doses of SPJ.(3)The results of immunohistochemistry showed that compared with the mice of the normal control group,the protein expressions of GRP78,CHOP,ATF6α,p-PERK,p-e IF2α,ATF4,p-IRE1α in the jejunal epithelial cells of mice on a high-fat diet increased significantly;compared with the mice of high-fat diet group,the protein expressions of GRP78,CHOP,ATF6α,p-PERK,p-e IF2α,ATF4 and p-IRE1α were significantly down-regulated after the administration of low-or high-doses of SPJ.(4)The results of HE staining showed that,a large number of lipid droplets in different sizes were accumulated in the epithelial cells of mice in the high-fat diet group compared with the mice of the normal control group,and the administration of SPJ could effectively reduce the accumulation of lipid droplets in jejunum of mice caused by an high-fat diet.(5)The results of triglyceride kit showed that the content of the triglyceride in the jejunum of mice fed with a high-fat diet was significantly increased compared with the normal control group mice,and the content of triglyceride in the jejunum of mice was significantly decreased after administration of high-doses of SPJ.(6)The results of real-time quantitative PCR showed that compared with the normal control group,the expressions of GPAT3 and DGAT2 m RNA associated with lipid metabolism in jejunal epithelial cells of mice on a high-fat diet were significantly increased,whereas the expression of ATGL m RNA significantly decreased;compared with the high-fat diet group,after the administration of low-and high-doses of SPJ,the expressions of GPAT3 and DGAT2 m RNA in jejunal epithelial cells of mice on a high-fat diet decreased effectively,and the expression of ATGL m RNA increased effectively.(7)The results of immunohistochemistry showed that compared with the mice of normal control group,the expression of PPAR-γ,a nuclear transcription factor,in jejunal epithelial cells of mice on a high-fat diet was significantly increased;compared with the high-fat diet group,the expression of nuclear transcription factor PPAR-γin jejunal epithelial cells of mice in low-dose and high-dose SPJ group was decreased.Conclusion SPJ can regulate lipid metabolism-related genes by down-regulating the expression of nuclear transcription factor PPAR-γ protein,improve lipid deposition,in jejunal epithelial cells of mice induced by a high-fat diet,and inhibit jejunal inflammation. |
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