| Abstract: | Abstract— The early effect of mechanical injury of the sciatic nerve in cats and rats on the amount of nucleic acids and on the number of Schwann cells was studied. The content of RNA and DNA increased at both ends of a severed nerve as early as 2 hr after operation; at 8 hr and up to 24 hr, their level was about twice as high as at the beginning of experiment. The increase in nucleic acids seemed to be chiefly due to their biosynthesis in the Schwann cells although the possibility of a contribution of axonal RNA must also be taken into consideration. The division of Schwann cell nuclei was observed not earlier than 36 hr after operation. The injury stimulates the synthesis of nucleic acids not only in the Schwann cells directly damaged, but also in those from neighbouring internodes. The increase in DNA and RNA observed 24 hr after a fresh lesion had been made in a degenerating nerve was smaller than the increase observed 24 hr after cutting or crushing a normal nerve. |
