求翻译：但由于自体雪旺细胞来源稀少，且通常要牺牲供区神经，因此使用受限。是什么意思？

However, autologous Schwann cell source rare, and usually have to sacrifice for the District nerves, so use is limited.

However, since the snow Mong source of the cell are scarce, and often have to sacrifice for the district nerves, and therefore use the restricted.

But because is scarce from the body snow prosperous cell origin, usually also must sacrifice for the area nerve, therefore uses is limited.

But because of the autogenous Schwann cell source rare, and usually to be sacrificed for neural, so the use of limited.

In addition to autologous nerve graft, the neural tube technology to some extent able to compensate for defects in nerve tissue, and promote recovery of neurological function. Schwann cells are now recognized as suitable for nerve tissue engineering seed cells.