Modification of sleep architecture in an animal model of experimental cirrhosis

To analyze the polygraphic sleep patterns during cirrhosis progression in a rat model by repeated CCl(4) administration.

Male Wistar rats received three weekly injections of CCl(4) for 11 wk, and were analyzed before and during the induction of cirrhosis. Rats were implanted with electrodes to record their sleep patterns. Polygraph recordings were made weekly over 11 wk for 8 h, during the light period. After a basal recording, rats received three weekly injections of CCl(4). Histological confirmation of cirrhosis was performed after 11 wk.

The results showed a progressive decrease in total wake time that reached statistical significance from the second week of treatment. In addition, there was an increase in total time of slow wave sleep (SWS) II and rapid eye movement sleep (REM sleep) in most of the 11 wk. SWS I showed no significant variations. During the final weeks, a significant increase in REM sleep frequency was also observed. Histological analyses of the livers showed unequivocal signs of cirrhosis.

These data suggest that hepatic failure produced by CCl(4) administration is capable of modifying the sleep pattern even after only a few doses.