[DNase I sensitivity of nucleus and chromatin in six different tissues of old rates].
In order to investigate the mechanism of aging, we studied the DNase I sensitivity of nucleus and chromatin in six different tissue (heart, liver, spleen, lung, kidney and brain of old and weanling wistar rats. The results showed that the DNase I digestive sensitivity levels of nucleus and chromatin in the tissue of the old rats were lower than those of the weanling rats respectively that in the old rats, the DNase I digestive sensitively in the tissue varied, the lowest sensitivity was in brain (P < 0.01); and that in the weanling rats, lowest DNase I digestive sensitivity of nucleus and chromatin was also in the brain, but the difference was not significant.