Construction Of TGF-β1Knock Down Transgenic Mouse Models And Their Roles In Spinal Cord Injury And Immunoregulation

[Objective]To construct the TGF-β1knock-down transgenic (TG) mouse models with aim to investigate the effect of TGF-β1on the recovery of Spinal Cord Injury (SCI) in mice.[Methods]To construct the TGF-β1gene know-down mouse models with TGF-β1hypo-expression by using gene manipulation. Polymerase chain reaction (PCR) was employed to identify the genotypes of mice. Western blot and immunohistochemistry (IHC) were used to examine the expression level and localization of TGF-β1in various tissues in the TGF-β1gene know-down mouse models of different genotypes.Following ascertaining the inhibition rate of TGF-β1in different tissues in TG mice, the mouse strain with the lowest TGF-β1down regulation rate was selected as the object of this study. And then, the monocytes were harvested from the peripheral blood of this mouse strain. Real-time PCR was used to detect the expression level of IL-1, IL-6, IL-10, NF-κB and TNFα in know down (do) mice in order to investigate the role of TGF-β1in immunoregulation. Moreover, T8spinal cord transected (SCT) mouse models were prepared, with aim to ascertain role of TGF-β1hypo-expression in the motor function in SCT mice.[Results]1. A total of5kinds of heterozygote transgenic descendants of TGF-β1-kd mouse strains were successfully constructed. In four of them, transgenic offspring could be generated and designed as Founder90, Founder12, Founder41and Founder46.2. The TGF-β1down-regulated rate in Founder90, Founder12, Founder41and Founder46, which were all TGF-β1protein levels know-down mice with TGF-β1hypo-expression, were57%,32%,18%and17%.3. TGF-β1immunopositive product distribution was observed in the olfactory bulb, the whole brain, spinal cord, skeletal muscles, lung, heart, spleen, kidney, adrenal glands, intestine and epidermis.4. There exists no prominent effect of TGF-β1gene hypo-expression on the level of expression in inflammatory factors, including IL-1, NF-κB and TNFα,which relative to that of WT mice (p>0.05). There was no expression of IL-6and TL-10mRNA detectable in the peripheral blood.5.The BBB Scores in TG mice with TGF-β1hypo-expression after SCI were markedly elevated relative to that of WT ones(P<0.05).[Conclusion]1.TGF-β1extensively up regulated transgenic mouse models were successfully constructed, and the down-regulated rates and systemic distributions of TGF-β1protein in four phenotypic transgenic mice with extensive hypo-expression of TGF-β1was provided, which paves a new way for sequent researches with regard to immunoregulation and spinal cord injury.2.TGF-β1gene down regulation had no influence on the level of inflammatory factors in peripheral blood in TG mice.3. TGF-β1gene down regulation promotes the recovery of motor function of hind limbs in SCT mice, suggesting that TGF-β1plays a crucial role in the plasticity of motor nerves following SCI in mice.