Abstract: Objective To explore the effect of sonic hedgehog (Shh) on the stem cell potential in cerebral cortical reactive astrocytes (RAS). Methods The astrocytes of cerebral cortex of SD rats were cultured in vitro. The inflammatory RAS were induced by tumor necrosis factor (TNF)-α, interleukin (IL)-1 α and C1q. The traumatic RAS were prepared by scratch test. The morphology and purity of cells were observed by immunofluorescence staining. The cells were divided into the normal astrocytes group (control group), the inflammation group, and the scratch group (trauma group). The inflammation group was cultured for 24 h after the intervention, control group and scratch group were cultured for 5 days. The positive rate of Nestin was observed by immunofluorescence staining. The expressions of Shh in different injured groups were detected by Western blot assay. Then, the cells in each group were replaced with neural stem cell culture medium on the 7th day, and cells were subdivided into the activation group (the group was replaced with neural stem cell culture medium and added with smoothened agonist) and inhibition group (the cells in each group were replaced with neural stem cell culture medium and then added with cyclopamine). After 14 days, the expression levels of RAS -induced neural stem cell related genes were verified by qRT-PCR. Results In cell injury model, the result of immunofluorescence staining showed that Nestin-positive cells were significantly more in the scratched group than those in the inflammatory group and control group. Western blot assay showed that the expression of Shh was significantly higher in the scratched group than that in the inflammatory group(P＜0.05). After replacing the neural stem cell conditioned medium, the expressions of neural stem cell genes (Nestin, Pax-6, Sox-2, Oct-4 and Map-2) were significantly higher in the scratch group than those in the inflammatory group and the control group (P＜0.01). After adding the cyclopamine, the gene expression levels were significantly reduced in the three groups, but the expressions of neural stem cell genes were significantly higher in the scratch group than those of the other two groups (P＜0.01). Conclusion In vitro, the Shh signaling pathway can mediate the potential of stem cells in the cerebral cortex RAS after injury.

Key words: astrocytes , genes, reactive astrocytes, Shh, SAG, cyclopamine, neural stem cell