济南军区总医院利用干细胞成功修复了受损神经细胞。其原理主要是依据(    )

阅读下面古诗词，回答相关问题。
                                                                                                          留别王维
                                                                                                           孟浩然
                                                                                               寂寂竟何待，朝朝空自归。
                                                                                               欲寻芳草去，惜与故人违。
                                                                                               当路谁相假，知音世所稀。
                                                                                               只应守寂寞，还掩故园扉。
     【注解】当路，当权者。假，提携。

若函数y=f(x) 在区间(a,b) 内可导,且$x_0\in \left(a,b\right)$, 则$\underset{h\to 0}{\lim }\frac{f(x_0+h)-f(x_0-h)}{h}$ 的值为（   ）