The Effects Of TGF-β1and The Astrocyte Conditioned Medium It Treated On Neuronal Dendritic Growth And The Expression Of Synapsinl

Objective To investigate the effects of TGF-β1and the astrocyte conditioned mediumit treated on neuronal dendritic growth and the expression of synapsin1,then analyze themechanism of neurological function recovery after brain injury and explore the linkbetween astrocytes and neurons.Methods Astrocytes were derived from newborn mice and subcultures. RNAinterference technique was used to interfere Smad3gene expression. And then RT-PCRwas conducted to determine the transfection efficiency. The cells were divided intogroups. They are TGF-β1at10ng·ml-1, Smad3-SiRNA-1, Smad3-SiRNA-2,Smad3-SiRNA-3and the control group. Astrocyte-conditioned medium was collectedwhen astrocytcs at passage2were cultured maintained at–20℃for use.The neuronswere derived from18days embryonic mouse. And divided them into two part.First,Dose-dependent effects of TGF-β1(1ng/ml to10ng/ml) on cerebellar neurons wereevaluated after48hours.Seconde,Put the astrocytes conditioned medium into theneurons,then to observed.The expression of microtubule associated protein-2(Map2)and Synapsin1were examined by immunocytochemistry staining respectivly Map2wasused to observe the neurite growth of dendritic. And the Synapsin1was used to measurethe expression changes of synapsin1by Multifunction Microplate Reader.Results (1)At concentrations of1ng/ml,5ng/ml and10ng/ml TGF-β1, the length of cerebellar neuronal dendritic cultured for48h was106.2±5.5,164.3±7.49,218.3±13.5respectively, which was significantly promoted compared with the control group(63.7±7.8)(P <0.05). Each dose group of TGF-β1can increase the expression ofsynapsin1. Meanwhile, the value of synapsin1fluorescence intensity was21940.7±870.0,38450.0±559.1,46067.5±1303.5respectively, which significantly increasedcompared with the control group (17608.3±1389.3)(P <0.01).(2) The length ofcerebellar neuronal dendritic in the group of TGF-beta was shorter, which wassignificantly promoted compared with the control group (P <0.05). The group ofTGF-β1can decrease the expression of synapsin1. Which significantly increasedcompared with the control group (P <0.01). While Smad3gene was successfullyinterfered, the consquences were reversed.Conclusion (1) TGF-β1can promote recovery of neurological function by promotingthe growth of dendrites of cerebellar neurons and the increase of synapsin1expression,which shows dose-dependent.(2) TGF-β1can restrain the growth of dendrites ofcerebellar neurons and the decrease of synapsin1expression.the TGF-β1-Smad3pathway is involved in the process.