Cerebrospinal fluid sampling by lumbar puncture in rats – repeated measurements of nitric oxide metabolites

Abstract

The ability to measure nitric oxide (NO) metabolites (NO 2 − plus NO 3 −: NO x ) in cerebrospinal fluid (CSF) will facilitate understanding the involvement of NO in neurogenic or inflammatory diseases. The purposes of this study were to develop a reliable method for CSF sampling from the lumbar region, and to repeatedly measure NO x in naïve rats. NO x in CSF were measured using the Griess method. Twelve young (13-week-old) and seven middle-aged (40-week-old) male Wistar rats were used. CSF (50–70 μl) was collected four times at 1-week intervals. The success rate of CSF collection was 96% and average surgery time was 21 min. The blood contamination rate was 11% on macroscopic inspection. NO x in the CSF ranged from 3.8 to 10.6 μM. The NO x in clear CSF were not significantly different from those with blood contamination on macroscopic inspection. There was, however, a linear correlation between the increase in NO x and the volume of venous blood added experimentally. NO x levels were significantly higher ( P < 0.05) in young rats (6.5 ± 0.2 μM) than in middle-aged rats (5.6 ± 0.3 μM). There was no significant difference in CSF NO x among the four samples collected at 1-week intervals in 13-week-old rats. These results indicate that our CSF sampling technique can be used to reliably obtain a small amount of CSF for NO x measurement. This technique will facilitate further experimental studies of the involvement of CSF NO in neurogenic or inflammatory diseases.