Feulgen-DNA changes in rat liver cell nuclei during the early phase of ischaemic necrosis

Summary

Cytophotometric comparison of the Feulgen-DNA contents of tetraploid nuclei from the left and median lobes of rat livers, after the left lobes had been ligated for different periods of time, yielded the following findings:

• 1. After ligation for 60 to 90 minutes, a small number of nuclei in the left lobe show a distinct decrease of the Feulgen-DNA content as compared with the nuclei of the control population (median lobe).

• 2. These outlying observations increase in number and decrease in measuring value with progressive duration of the period of ischaemia, until after 6 hours' ligation the mean Feulgen-DNA value of the nuclei in the left lobe amounts to 75.9% of the mean for the control population. After 1–2 hours of ischaemia, the mean value is hardly influenced by the outlying observations which in this early stage are still very scarce.

• 3. 24 hours after 60 minutes' ischaemia, followed by restoration of the circulation, the populations of the measured values of the left and the right lobe overlap entirely. The day after 90 minutes of temporary ischaemia, the majority of the nuclei in the left lobe are distributed over values that vary from 20 to 80% of the control mean; there is still a small proportion of nuclei with a Feulgen-DNA value within normal limits. The number of these lastmentioned nuclei decreases with the period of temporary ischaemia, until it is reduced to 0 after 6 hours' ligation.

It is concluded from these experiments that in liver tissue of the rat after a period of 60 to 90 minutes total ischaemia, the majority of the liver cells are damaged irreversibly and that a progressive and highly variable loss of DNA from the parenchymal nuclei, as a part of incipient necrosis, starts immediately afterwards. This principle can be applied elsewhere, e.g. in tracing cells in the early phases of necrosis.