Early changes in protein synthesis following spinal cord hemisection in the Cebus monkey (Cebus apella)

The short term effects of spinal cord hemisection on protein synthesis in the Cebus monkey were studied by measuring the uptake of [3H]lysine into the trichloroacetic acid (TCA) precipitable and non-precipitable fractions of spinal cord. Animals were sacrificed 3, 6, or 13 days after hemisection. Two normal animals and a 3 day sham operate were utilized as controls. All data were pooled and subjected to analysis of variance. Significant group differences were resolved by a standad t-test over pooled operative group samples and a paired t-test for left-right differences within groups. Compared to normal animals, significant increases in the mean uptake of precursor into TCA precipitable and non-precipitable fractions of spinal cord samples were noted in all postoperative groups. The observed increase in the uptake of [3H]lysine into TCA soluble and insoluble fractions at 3 days after hemisection were attributed to stress, as were increases in the activity of the TCA insoluble fractions in the sham operate. By 6 days, the increases attributed to stress in the average protein activity seemed to subside, resulting in an overall decrease in the TCA precipitalbe protein activity with an increase in TCA soluble fraction activity. Between 6 and 13 days the activity of the TCA soluble and insoluble fractions returned to the 3 day levels with a sharp increase in the activity of both fractions in the area of the hemisection. This increase was attributed to increases in neuronal, neuroglial, and infiltrating cell metabolism possibly associated with regenerative changes.