Effect Of Neuropeptide Y On Expression Of NaPi-Ⅱb Protein And Absorption Of Inorganic Phosphorus In Porcine Small Intestinal Epithelial Cells

This experiment was conducted to investigate the effect of different concentration of neuropeptide Y on gene transcription and protein expression of NaPi-IIb and absorption of inorganic phosphorus through culturing and establishing the model of porcine small intestinal epithelial cells in vitro. To interpret the regulation mechanism of inorganic phosphorus absorption affected by neuropeptide Y, and provide experiment basis for further study on animal phosphorus absorption and regulatory mechanism.Six treatments were designed of concentration of neuropeptide Y, and the control group without neuropeptide Y, other treatments of adding different concentration of neuropeptide Y (10-11mol/L,10-10mol/L,10-9mol/L,10-8mol/L and10-7mol/L), respectively, with six or eight repetition each treatment. Proliferation of porcine small intestinal epithelial cells was determined by MTT assay. Phosphorus content of the cell supernatant fluid was detected by phosphorus detection kits. The relative expression quantity of porcine small intestinal epithelial cells NaPi-IIb mRNA was detected by RT-PCR. The relative expression levels of NaPi-IIb protein was detected by western blotting. The main results were as follows:There was no difference (P>0.05) on cell proliferation in each treatment group, stimulating intestinal epithelial cells with different concentration of neuropeptide Y after24hours:Phosphorus content of the cell supernatant fluid declined over time, and there were significant linear (P＜0.01) and quadratic (P<0.01) correlations. Neuropeptide Y and phosphorus content were very significantly correlated (P<0.01) after24hours. Compared with the control group, the treatment group of10-10mol/L,10-9mol/L,10-8mol/L and10-7mol/L very significantly (P<0.01) decreased phosphorus content, and the amount of phosphorus uptake in small intestinal epithelial cells increased by161%,171%,168%and139%respectively than the control group.Compared with the control group, the treatment group of10-11mol/L,10-10mol/L,10-9mol/L and10-8mol/L significantly (P<0.05) increased relative expression quantity of NaPi-IIb mRNA. There was significant quadratic correlations between relative expression quantity of NaPi-IIb mRNA and neuropeptide Y (P<0.01).Compared with the control group, the treatment group of10-10mol/L,10-9mol/L and10-8mol/L significantly (P<0.05) increased relative expression levels of NaPi-IIb protein. There was significant quadratic correlations between relative expression levels of NaPi-IIb protein and neuropeptide Y (P<0.01).In a word, we concluded that the appropriate concentration of neuropeptide Y can stimulate NaPi-IIb gene transcription, increase expression levels of NaPi-IIb protein, and then induce inorganic phosphorus in the extracellular fluid to transport across the membrane into the intracellular fluid, so as to promote the absorption of porcine small intestinal epithelial cells to inorganic phosphorus, and the optimum concentration of neuropeptide Y in the cell culture fluid between10-10mol/L～lO-8mol/L...