The Expression Of Growth Hormone Releasing Factor In Rabbit Liver And Muscle Tissue And Its Effect On Growth

Growth Hormone Releasing Factor (GRF) can specifically stimulate Growth Hormone realsing. so it can improve animals growth rate. It has potential and extensive applications in husbandry. The recombinated plasmids containing GRF gene were expressed in liver and muscle respectively by different ways. And the effects on growth were investigated on rabbits.The orientation expression in rabbit livers and its effect on growth.Receptor-mediated gene transfer has been used to introduce exogenous gene into specific tissue of animals in vivo and expression were observed. In this experiment, the recombinated pcDNAS plasmids containing GRF gene were specifically deliveried into rabbits' livers by asialoglycoprotein receptor-mediated phagocytosis. The plasmid containing GRF gene were extracted, purificated and calculated. Poly-L-lysine(PLL) and a -D-Galactopyranosylphenyl Isothiocyanate(Gal) were dissolved in Na2COs solution(0.1mol/L, pH 9.6) in 4:1 (molar ratio). The tube containing the solution was shielded from light and solution was mixed for 24 hours in room temperature and then dialyzed in cellophane against 500ml of 5mmol/L NaCl for 24 hours with one change for 6 hours. The pcDNA3-GRF plasmid was dissolved in 0.7mol/L NaCl solution and vortexed in medium speed, then Gal-PLL solution were added into vortexed DNA solution drop by drop hi the mass ratio 1:3.16 to plasmid DNA. Then 5mol/L NaCl solution was added into it slowly and the last concentration of NaCl in the solution was regulated to 1.031mol/L. The DNA/Gal-PLL complexes were observed with electron microscope. The complexes were spherical and 10-100nm in diameter in this concentration of NaCl. The complexes containing Img pcDNA3-GRF plasmid were injected into ear margin vein of adult rabbits. The liver, lung and kidney tissue were collected on 7 and 27day after administration. Total RNA of those tissues were extracted. GRF mRNA were detected by RT-PCR. GRF protein was detected by indirect ELISA. The expressions of GRF gene were detected in livers on 27 days after administration. The function of improving growth rate was detected on 10 rabbits. Those rabbits were separated into 2 groups at random. Saline (A), DNA/lignad complexes (B) were injected into rabbits' ear margin vein respectively. Weight of those rabbits were measured when injecting and on the 5th, 10th, 15th, 20th, 25th, 30th day after injection. The datum were disposaled by statistics methods. The results showed that the function of improving rabbits growth rate of DNA/ligand complexes was significant comparing to saline.The expression in rabbit muscles and its effect on growth.Protoplast containing pcDNA3-GRF were prepared. The fusion between protoplast and48cells of muscle were investigated by electron microscope. Following, the effects on growth were investigated. 10 rabbits were separated into 2 groups at random. Protoplast without pcDNA3-GRF plasmid(A), protoplast containing pcDNA3-GRF plasmid(B) were injected into rabbits muscles of hindlimb respectively. Weight of those rabbits were measured when injecting and on 5th, 10th, 15th, 20th, 25th, 30th day after injection. The data were disposaled by statistics methods. The results showed that the function to improve growth rate of protoplast containing pcDNA3-GRF plasmid was significant comparing to protoplast without pcDNA3-GRF plasmid.