Twenty-four-hour disruption of the sleep-wake cycle and sleep-onset REM-like episodes in a rat model of African trypanosomiasis.
OBJECTIVE
Patients with human African trypanosomiasis (sleeping sickness) due to the inoculation of Trypanosoma brucei gambiense or rhodesiense show a major disruption of the 24-hour sleep-wake distribution, accompanied by the occurrence of sleep-onset rapid-eye-movement (REM) sleep episodes, proportional to the severity of the illness. Although animal models of human African trypanosomiasis have been developed to understand the pathogenic mechanisms leading to immune alterations, the development of an animal model featuring the alterations of endogenous biologic rhythms remains a necessity.


METHODS
Sprague-Dawley rats (N = 10) entrained to a 12:12-hour dark-light regimen.


METHODS
Rats were infected with Trypanosoma brucei brucei AnTat 1.1E and instrumented with electrocorticographic and electromyographic electrodes. Polysomnography was recorded continuously from 2 days before infection until the animal's death.


RESULTS
The analysis of the spontaneous sleep-wake architecture revealed an increased proportion of slow-wave sleep (SWS) and a decreased amount of wakefulness 2 days before death. Considerable sleep fragmentation was observed in the infected rats, with numerous changes in sleep-wake stages and an increased number of episodes of wakefulness and SWS. Infected rats presented a fragmented pattern of SWS and a marked reduction in the mean paradoxical-sleep (PS) latency, resulting in a considerable disruption of the PS-SWS sequences. Abnormal transitions, particularly the appearance of sleep-onset REM episodes, marked the disruption of the internal sleep structure. The electrocorticogram traces were modified during SWS, with the occurrence of abnormal hypersynchronic slow waves and a disappearance of spindles.


CONCLUSIONS
The Trypanosoma brucei brucei-infected rat is a good model of the syndrome seen in human African trypanosomiasis, ie, the 24-hour disruption of the sleep-wake cycle and the occurrence of sleep-onset REM-like sleep episodes.
Centre de recherches du Service de santé des armées, département des facteurs humains, B.P 87, F-38702 La Tronche cedex, France. a_darsaud@yahoo.com
Annabelle
A
Darsaud
Lionel
L
Bourdon
Sarah
S
Mercier
Florian
F
Chapotot
Bernard
B
Bouteille
Raymond
R
Cespuglio
Alain
A
Buguet
D000818:Animals; D021081:Chronobiology Disorders / Q000503:physiopathology*; D004576:Electromyography; D008297:Male; D017286:Polysomnography; D051381:Rats; D017207:Rats, Sprague-Dawley; D020178:Sleep Disorders, Circadian Rhythm / Q000469:parasitology* / Q000503:physiopathology*; D012895:Sleep, REM / Q000502:physiology*; D013997:Time Factors; D014346:Trypanosoma brucei brucei; D014353:Trypanosomiasis, African / Q000150:complications*