Study Of Raw Soybean And Excessive Protein Diet Inducing Oxidative Stress In Digestive Organs Of Mice

Oxygen free radical is related to many diseases,for example,diabetes,obesity, inflammatory bowel,cardiovascular disease and so on.Oxidatie damage of digestive system is very serious under the condition of chronic stress..Digestive system includes digestive,absorbtive and metabolic organs.Excessive free radicals can induce deseases of digestive system.The aim of our experiment was to study the effect of soybean trypsin inhibitor and the kind and level of dietary protein on digestive system.1.The effect of raw soybean on redox state of the peptic and gland alveolus function of pancreas in miceThe objective of the this study was to investigate the effect of STI on redox state of the digestive system and gland alveolus function of pancreas in mice.A total of 108 male,KM mice weighing 12-14g,have been used for the experiments.The One hundred and eight were randomly divided into nine groups of 12 each:group 1,basic diet;group 2,basic diet supplemented with 30mg/kg cysteamine;group 3,basic diet supplemented with 60mg/kg cysteamine;group 4,basic diet containing low level of STI;group 5,basic diet containing low level of STI supplemented with 30mg/kg cysteamine;group6,basic diet containing low level of STI supplemented with 60mg/kg;group 7,basic diet containing high level of STI;group 8,basic diet containing low level of STI supplemented with 30mg/kg cysteamine;group 9,basic diet containing low level of STI supplemented with 60mg/kg cysteamine.Mice were fed for two weeks.The effect of STI on the redox state and gland alveolus of pancreas in were evaluated by determination of oxidative and antioxidative indexes in plasma and the digestive system,and activities of amylase,lipase and trypsin.The results show higher content of oxidative index STI and lower level of antioxidant index were found in plasma and duodenum,liver and pancreas in the basic diet containing STI(P＜0.05);STI caused pancreas pancrease hypertrophy,and significantly lowed activities of amylase,lipase and trypsin in plasma,duodenum and pancreas.These result was dependent-level of STI.A balance between oxidatant and antioxidant was improved and lesion of pancreas was lessened by cysteamine.These results strongly suggest that damage of STI on pancreas was related to production of free radicals.2.The effect of dietary protein origin and level on the redox status in peptic of miceTo study the effects of dietary protein kind(soybean protein or casein) and level on a balance between free radicals production and antioxidant level in digestive organs of mice and the dynamic change of ROS level.A total of 72 male,C57BL/6J mice weighing 12-13g,have been used for the experiments.The seventy-two were randomly divided into six groups of 12 each:group 1,control diet containing casein; group 2,excessive protein diet containing casein;group 3,excessive protein diet containing casein supplemented with 60mg/kg cysteamine;group 4,control diet containing soybean;group 5,excessive protein diet containing soybean;group 6, excessive protein diet containing soybean supplemented with 60mg/kg cysteamine. Mice were fed for two weeks.In addition,the one hundred and eight mice were randomly divided into nine groups of 12 each:group 1,before intake,that is,0h;other eight groups were 0.5h,1.0h 1.5h and 2.0h after intake(casein and soybean protein). Oxidative and antioxidative levels in digestive system,organs weight and viscera indexes in mice,ROS level in blood,jejunum,duodenum,liver and pancreas,and the scavenging effect of soybean and casein hydrolysate on DPPH and·OH in vitro were determined.The results show that ingestion of excessive protein markedly increased contents of superoxide anion and MDA and decreased activities of SOD,GSH-Px, CAT and Na~+K~+-ATPase,and content of GSH in duodenum,liver and pancreas of mice(P＜0.05).Levels of oxidative parameters were lower and antioxidant capacity of both enzyme and non-enzyme was higher in mice fed with soybean protein than those fed with casein in vivo.The scavenging capacity of soybean hydrolysate on DPPH and·OH was stronger than that of casein hydrolysate in vitro.In groups fed excessive protein diets supplemented with cysteamine,oxidative stress was mitigated;however, oxidative parameters levels were still higher than those of control diet-fed groups. ROS level showed the dynamic change with time after intake,and the whole level of ROS was highest at 1.0h.Based on above results,it was concluded that a balance between oxidant and antioxidant was destroyed,furthermore,oxidative stress was induced by excessive protein diet.3.The study of excessive protein diet on pancreas function and oxidative damageTo estimate the effect of excessive protein diet on free radicals and the pancreas function in mice,thirty-six mice with an average weight of 12-13g were randomly divided into three groups of twelve each.The mice received control diet,excessive protein diet and excessive protein diet supplemented with 60mg/kg cysteamine, respectively,for 14 days.Organs weight and viscera indexes,protein,DNA and RNA concentration in pancreas,oxidative and antioxidative levels,digestive enzyme activity,and level of somatostatin and insulin in plasma and pancreas in mice were determined.The results show that ingestion of excessive protein markedly increased contents of superoxide anion(225%and 481.82%) and MDA(91%and 185.19%) and decreased activities of SOD,GSH-Px,and T-AOC(P＜0.05).Pancreas weight and concentration of protein,DNA and RNA were significantly increased.But capacity of islet cell secretion was enhanced,that is,levels of somatostatin and insulin were enhanced(P＜0.05).Cysteamine improved the above symptom.These results show excessive protein diet might cause the increase of free radicals levels and oxidative damage,and influence pancreas function.4.The effect of excessive protein diet on gene expression of intestine in miceA total of 24 C57BL/6J male mice of an average body weight of 12-13g were randomly allocated to two dietary treatments of twelve each:control diet and excessive protein diet.These animals were fed for two weeks.The effect of excessive protein diet on gene expression of intestine in mice was estimated by gene chip.The results show excessive protein diet made genes of 714 up-regulated and genes of 458 down-regulated,and influenced gene expresstion of intestine at biological process,molecule function and cell component,mainly including oxidoreduction,metabolism,transport,immune response,defense reaction and signal conduction.We found that there were 63 Permute P less than 0.05 and 3(B cell receptor signaling pathway,Protein histidine kinase activity, Mitochondrial-Carnitine-Palmitoyl transferase-CPT-System-BioCarta) Adjusted P less than 0.05 by analyzing GenMAPPs datacase.Excessive protein diet induced up-regulation of Apoe,Gpx2,Cyba,Noxo1,Cat and Scd1 and so on related oxygen and reactive oxygen species metabolism(Cat,FC=2.143547),and genes expression of glutathione metabolism and glutathione transferase including Gpx2,Gsta1/Gsta2,Gstm1,Gstm2 and so on.In addition,excessive protein diet had wide effect on gene expression of metabolism of amino acid,protein,lipid and glucose.Gene of somatostatin was up-regulated and FC of it was 1.515717.5.The effect of excessive protein diet on gene expression of liver in miceA total of 24 C57BL/6J male mice of an average body weight of 12-13g were randomly allocated to two dietary treatments of twelve each:control diet and excessive protein diet.These animals were fed for two weeks.The effect of excessive protein diet on gene expression of liver in mice was estimated by gene chip. The results show excessive protein diet made genes of 381 up-regulated and genes of 300 down-regulated,and influenced gene expresstion of intestine at biological process, molecule function and cell component,mainly including oxidoreduction,metabolism, transport,immune response,defense reaction and signal conduction.We found that there were 73 Permute P less than 0.05 and 7(Cholesterol Biosynthetic Process, Sterol Biosynthesis,Alkaloid BiosynthesisⅡ) Adjusted P less than 0.05 by analyzing GenMAPPs datacase.Excessive protein diet induced up-regulation of major of genes related oxygen and reactive oxygen species metabolism and down-regulation of three genes including Scd1(FC,-4.92458),Mt2,Sod1,and genes expression of glutathione metabolism and glutathione transferase including Gpx2,Gpx1,Gpx4,Gstt2,Gstt1,Gstt3,Gsta4,Gstp1 and so on.In addition,excessive protein diet had wide effect on gene expression of metabolism of amino acid,protein,lipid and glucose.