| Diabetic enteropathy is one of the common complications of diabetes mellitus.Diabetic enteropathy leads to disturbance of the intestinal electrophysiology,disturbance of the intestinal nerves and prolonged passage of food through intestines,which leads to overgrowth of microorganisms in intestines and bile salt decomposition,resulting in diarrhoea,which in turn leads to inflammation of intestines.The project investigated the nutritional modulation and nutritional efficacy of diabetic food formulations to improve the inflammatory properties of the diabetic intestine and the immunomodulatory effects of L-arginine in diabetic food formulations.A mouse model of intestinal epithelial cell hyperglycaemic injury was established to demonstrate the immunomodulatory effects of L-argine.The intestinal epithelial cell were stimulated with high sugar to establish a simulated intestinal oxidative stress system,and L-arginine was used to evaluate the establishment of the simulated high sugar injury model and its antioxidant properties.The concentrations of L-arginine in intestinal epithelial cell were determined to be 0,0.001,0.005,0.01,0.02 and 0.04mmol/L.The concentration of glucose in intestinal epithelial cell was designed to be 70mmo/L.L-arginine was incubated with intestinal epithelial cell under high glucose conditions for 8 h.After incubation,the cells were assayed for lactate dehydrogenase,superoxide dismutase,glutathione peroxidase and catalase were measured at the end of incubation,and the enzymes in the high sugar group were 88.79 U/L,5.07 U/m L,5.89μmol/L,156.82 U/m L,L-argine significantly reduced LDH activity in cells to80.00-84.56 U/L,increased SOD,GSH,CAT by 5.15-7.37 U/m L,6.52-10.04μmol/L,184.99-225.71 U/m L,indicating that L-arginine has antioxidant capacity.The addition of L-arginine to intestinal epithelial cell mimicking a high glucose injury model was co-cultured with TNF-α,IL-1β,and Ig G in the high glucose group at 113.33 ng/L,98.67ng/L,and 1.34 mg/m L,respectively.L-arginine significantly reduced the cellular viability of TNF-αand IL-1βto 88.00-107.00 ng/L,60.67-75.33 ng/L and increased Ig G levels to 1.82-2.16 mg/m L,indicating the immunomodulatory ability of L-arginine.The immune effects of L-arginine and the enteral nutrition preparation with silkworm pupae protein component(ENS)were enhanced in the mouse inflammatory intestinal system.LPS-induced inflammation was induced in the isolated intestine of mice with intestinal fluid to form an in vitro small intestinal system.H&E staining was used to analyze the histomorphology of mouse small intestine.Immunohistochemical staining was performed to detect the number of CD4~+T lymphocytes in the mouse small intestine.Elisa results showed that compared to the LPS group,L-arginine and ENS were able to significantly reduce the levels of TNF-α,IL-1β,IL-6(P<0.05)and significantly increase the levels of s Ig A,Ig G,Ig M,Pep T1,FATP4,GLUT2(P<0.05).The H&E results showed that compared with the LPS group,the small intestinal villi were more intact without significant detachment and necrosis,and the mucosal layer and the structure of the submucosa was clear,the muscular layer was not thinned and the inflammatory cell infiltration was reduced.Immunohistochemical staining showed that L-arginine and ENS reduced the sharp increase in CD4~+T lymphocytes caused by LPS stimulation,indicating that L-arginine and ENS effectively carried out cellular immunity,reduced the inflammatory response of the intestine caused by LPS stimulation and maintained the immune function of the small intestine.L-arginine and ENS enhanced immune effects in the intestine of mice.L-arginine modulated the immune effect of the enteral nutrition preparation with the silkworm pupae protein component by administering different doses of L-arginine and ENS to mice and inducing intestinal inflammation by LPS intraperitoneal injection.Intestinal electromyography showed a significant decrease in slow wave frequency and amplitude in the small intestine of the LPS treated group compared to the control group(P<0.05)indicating an inflammatory response in intestines.Blood indicators showed that ENS significantly increased(P<0.05)the levels of white blood cells,red blood cells,haemoglobin and platelets compared to the LPS-treated group.The secretion levels of IL-1β,TNF-α,IL-6 and IL-10 inflammatory factors were measured by ELISA,and the results showed that ENS was able to significantly decrease(P<0.05)the levels of inflammatory factors compared with the LPS-treated group.The secretion levels of Ig M,Ig G and ZO-1 were measured,and the results showed that ENS was able to significantly increase(P<0.05)the levels of Ig M,Ig G and ZO-1 compared with the LPS-treated group.The results of H&E staining showed that ENS significantly improved the LPS-induced intestinal tissue damage and reduced inflammatory factor infiltration in mice.The results of immunohistochemical staining showed that ENS could reduce the proliferation of CD4~+T lymphocytes and increase the expression of s Ig A protein,maintaining a stable microenvironment in the small intestine.Studies have shown that in vitro system L-arginine enhances the immune action and antioxidant capacity of epithelial cells.In the Ex vivo system,L-arginine and the enteral nutrition preparation with silkworm pupa protein components reduce the secretion of inflammatory factors,increase the level of immunoglobulins and the metabolism of nutrients.In the In vivo system,L-arginine modulates the immune effect of the silkworm pupa protein enteral nutrition preparation on the small intestine,relieves intestinal diarrhoea and improves intestinal motility,regulates the balance of blood parameters,reduces inflammatory factors and increases immunoglobulins and tight junction proteins.This study provides a theoretical basis for the mechanism of action of L-arginine and ENS in regulating intestinal immunity,and for the use of L-arginine as a unique element in enteral nutritional preparations to improve intestinal immunity in animals,enhance the immunity of the body,reduce inflammation in the body,enhance nutrient absorption,and provide a scientific basis for the development of formulations for special medical purposes. |
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