ABSTRACT
This study aimed to elucidate the effect of tryptophan (Trp) on gut hormone secretion as well as the roles of the calcium-sensing receptor (CaSR) and its downstream signaling pathway in gut hormone secretion by assessing swine duodenal perfusion in vitro. Swine duodenum was perfused with Krebs-Henseleit buffer as a basal solution. Various concentrations (0, 10, and 20 mM) of Trp were applied to investigate its effect on gut hormone secretion. A CaSR antagonist was used to detect the involvement of CaSR and its signal molecules. The 20 mM Trp concentration promoted the secretion of cholecystokinin (CCK) and glucose-dependent insulinotropic peptide (GIP), elevated the mRNA level of CaSR, and upregulated the protein levels of CaSR, protein kinase C (PKC), and inositol trisphosphate receptor (IP3R). However, NPS 2143, an inhibitor of CaSR, attenuated the CCK and GIP release, reduced the mRNA level of CaSR, and decreased the protein levels of CaSR, PKC, and IP3R with 20 mM Trp perfusion. The results indicate that CCK and GIP secretion can be induced by Trp in swine duodenum in vitro, and the effect is mediated by CaSR and its downstream signal molecules PKC and IP3R.
Subject(s)
Cholecystokinin , Duodenum , Gastric Inhibitory Polypeptide , In Vitro Techniques , Inositol , Perfusion , Protein Kinase C , Receptors, Calcium-Sensing , RNA, Messenger , Swine , TryptophanABSTRACT
BACKGROUND:It is reported that the cellsurface antigen may be damaged by the trypsin enzyme in some extent and the cellactivity may also be influenced, as a result of which, the subsequent separation and fol ow-up-test wil be affected. Accutase enzymes possess the activities of protease and col agen enzyme and need no special termination or cleaning at the end of digestion. Another special function of accutase enzyme is to protect cellsurface antigen and thus it has been widely applied in the stem celldigestion and culture. OBJECTIVE:To compare the digestive effect of accutase enzymes and trypsin enzyme in the separation and original culture of spermatogonial stem cells. METHODS:The testes of 5-7 days male Kunming mice (n=45) were col ected and primarily digested with col agenas. The suspension of digested tissue was divided into three parts with the same volume named accutases enzyme group, trypsin enzyme group and mixed enzyme group (trypsin enzyme and hyaluronidase). For the comparison of testis digestive status and the time required for the formation of single cells, the micrographs were taken at 1, 3 and 5 minutes respectively after enzyme digestion. The total number and the mortality of the single cells were estimated and compared. The leydig cells and sertoli cells were removed by differential adherent method and the remained spermatogenic cells were then treated with CD90.2 immune magnetic beads. The selected spermatogonial stem cells were subsequently labeled by glial cellline-derived neurotrophic factor receptor alpha-1 and sorted with flow cytometry. The number of spermatogonial stem cells positive for glial cellline-derived neurotrophic factor receptor alpha-1 in CD90.2+and CD90.2-cells was compared within different groups. RESULTS AND CONCLUSION:The digestive capacities of different enzyme were different. Accutases enzyme obtained the single cellsuspension more quickly than trypsin enzyme and mixed enzyme, and had the least cellmasses and broken cellmembrane than the other two groups. After the differential attached treatment, the highest total number of CD90+spermatogonial stem cells and lowest cellmortality could be found in the accutases group, when compared with the other groups. The results of cellsorting by flow cytometry showed a higher rate (72.24%) of GFRα1+/CD90+cells in the accutases group than the trypsin group (51.16%) and mixed enzyme group (71.27%). The GFRα1+/CD90-number in the accutases group was lower (15.03%) than that of the trypsin group (18.8%) and mixed enzyme group (24.23%), respectively. The results indicate a better effect of accutases enzyme on the primary separation of spermatogonial stem cells than that of trypsin or mixed enzyme.
ABSTRACT
Dietary essential amino acids are extracted in the first-pass metabolism by the small intestine.Besides incorporation into mucosal protein,they are also the fuels for the utilization by small intestinal mucosal cells and the precursors for intestinal synthesis of new amino acids and enormous biological important molecules such as glutathione,polyamines,etc.Thus,their gut metabolism is not only crucial for the maintenance of the integrity and function of intestinal mucosa,but also important for the regulation of whole body metabolism.
ABSTRACT
With the improvement of living conditions,people pay more attention to food sanitation,following which the incidence rate of food allergy is higher and higher.Food allergy threatens public health seriously.It is caused mainly by dominance of T helper type 2-based immune responses,which breaks the dynamic balance of Th1/Th2 immune responses and resultes in over secreting of IL-4,IL-5 and IL-13,production of specific antibody IgE,degranulation of mast cells,alteration of intestinal microflora and so on.At present,a lot of investigations have been reported,of which the probiotics therapy attracted more attention.As the indigenous flora,probiotics could not only prevent and treat food allergy but could also modulate immune responses and recover the dynamic balance of it via secreation of cytokines such as IFN-?,IL-10,TGF-?.
ABSTRACT
Objective: To study bacterial and lactobacilli communities in stomach of neonatal piglets from 7 to 35(two weeks after weaning) days of age.Methods: The semi-quantitative Dilution-PCR,PCR-DGGE and sequencing were used to analyze the shifts of stomach total bacterial and lactobacilli community.Results: Stomach pH value was around 3.0 before weaning and increased apparently after weaning.Dilution-PCR showed that bacterial concentration in stomach of piglet was very low before weaning and increased significantly after weaning.The DGGE profiles from total bacteria in stomach showed that the bands of samples before weaning were very simple and the predominant band belonged to high GC bacterium.After weaning,some new predominant bands appeared and the previous high GC bacteria disappeared simultaneously.Sequence analysis indicated that these new bands were Escherichia fergusonii,Escherichia coli,Streptococcus gordonii and Streptococcus suis,all of which were potential pathogens for piglets.The similarity of DGGE profiles from stomach lactobacilli showed weaning stress had no obvious effect on lactobacilli community.Conclusion: Weaning stress could cause stomach pH increase apparently and induce potential pathogens proliferation in stomach of piglets.
ABSTRACT
OBJECTIVE:To study the effects of Xinghuang tablets on tumor growth and immunologic function in S 180 sarcoma-bearing mice.METHODS:The model of mice with S 180 sarcoma were given Xinhuang tablets intragastrically to ob?serve the effects on the ratio of tumor to body,the inhibition rate of tumor,the indices of the spleen and thymus,and the rate of micronuclei in PCE in bone marrow of the mice.RESULTS:The body weight of the mice with S 180 sarcoma was decreased;the growth of the tumor was inhibited;the weight of spleen was increased;the number of leucocyte of peripheral blood was raised(P