Glutamine: The Effect Of Gastrointestinal Protection In Newborn Rats

Objectives:Recent literatures have focused on the role of glutamine in the area of nutrition and metabolism.We carried on this Gln-related research with the expectation to better nourishment support to critically-ill children.To observe the changes of the intestinal tract of the maternal breast-fed newborn rats,we deprived glutamine(Gln) artificially by depressing glutamine synthetase(methionine sulfoximine,MS) in mother and/ or baby rats.Also,newborn rats model with endotoxemia were used to observe the effect of Gln supplementation to intestinal function.Methods:First part of the experimentNewborn rats were divided into 5 groups.All rats were breast-fed.Group 1,the control group,consisted of rats and maternal rat without MS injection into the abdominal cavity.Group 2 consisted of rats with maternal use of MS through intraperitoneal injection from the 3rd day of given birth for 6 days.Group 3 consisted of rats with maternal use of MS from the first day given birth for 6 days.Group 4 consisted rats who were injected MS from the 3rd day on,maternal rat used MS from the 3rd day of given birth,both for 6 days.Group 5 consisted of rats with MS from the 3rd day of life until day 9,without maternal use of MS.All newborn rats were killed.Small intestine was harvested for morphological studies.Changes of the small intestine villi were observed by light microscope and electron microscope.Membrane fluidity of intestinal epithelial cell was examined, too.Second part of the experimentNewborn rats were divided into 4 groups.Group 4(Gln completely-deprived model) from the first part experiment as experiment set and the normally fed rats as control set.Gln completely-deprived model:rats who were injected MS from the 3rd day on,maternal rat used MS from the 3rd day of given birth.normally fed rats:rats and maternal rat without MS injection into the abdominal cavityGroup 1 consisted Gln completely-deprived rats whom used Gln through intraperitoneal injection from the 3rd day for 6 days.Group 2 consisted Gln completely-deprived rats without Gln supplementation for 6 days.Group 3 consisted normally fed rats whom used Gln through intraperitoneal injection from the 3rd day for 6 days.Group 4 consisted of rats and maternal rat without use ofmethionine sulfoximine All newborn rats were uesd LPS through intraperitoneal injection in the 7th day of experiment.After 6 hours the rats were killed.Small intestine was harvested for morphological studies.Changes of the small intestine villi were observed by light microscope and electron microscope,and the membrane fluidity of intestinal epithelial cell was examined.Results:In the first experiment,the morphology of small intestine was significantly different in each group.In the control group small intestine villi and microvilli were slender,developed,arranged closely and intestinal structure was clear under optical and electric microscopics,the membrane fluidity of intestinal epithelial cell was best in all groups.By the contrast,the small intestine villi and microvilli in group 4 were badly destroyed and arranged,the membrane fluidity of intestinal epithelial cell was worst among all groups.In the second part of the experiment,the morphology of small intestine of rats with endotoxemia was significantly different in each group.In group 2 intestinal structure was not integral,small intestine villi and microvilli were the shortest and badly destroyed under optical and electric microscopics,the membrane fluidity of intestinal epithelial cell was worst in all groups.However,due to the additional Gln supplementation,the destroyed small intestine villi and microvilli of group1 were alleviatived compared to group 2,so does the membrane fluidity of intestinal epithelial cell.The morphology of small intestine was not significant changed between group 3 and group 4,but both of them were better than the former two groups.Conclusions:(1) The experiment showed that Gln deprivation can really change the gastrointestinal structure and function of newborn rats.(2) The 4th group will be the most suitable animal model for Gln deficiency model in breast-fed baby rats.(3) The study preliminary certified that Gln supplement could protect the gastrointestinal structure and function in newborn rats during endotoxemia.