Comparative analysis of neurofilament light chain levels in the serum and cerebrospinal fluid in rats subjected to partial sciatic nerve ligation

Neurofilament light chain (NfL) has recently been used as a biomarker of neurodegeneration. Although cerebrospinal fluid (CSF) NfL levels are hypothesized to affect blood NfL levels, whether blood NfL levels change independently of the CSF during peripheral nerve injury remains unclear. Thus, we evaluated the nervous tissues histopathology and serum and CSF NfL levels in partial sciatic nerve-ligated rats at 6 h and one, three, or seven days after the surgery. Sciatic and tibial nerve fiber damage was observed at 6 h after the surgery, and peaked at three days postoperatively. The serum NfL levels peaked 6 h to one day after ligation, but they tended to return to the normal seven days after ligation. However, the CSF NfL levels were unchanged throughout the study period. In conclusion, the comparative evaluation of serum and CSF NfL levels can provide useful information as biomarkers of nerve tissue damage and its distribution.