Increased disease activity is associated with altered sleep architecture in an experimental model of systemic lupus erythematosus.
OBJECTIVE
The aim of this study was to evaluate sleep patterns during the course of the disease in (NZB/NZW)F1 mice, an experimental model of systemic lupus erythematosus (SLE).


METHODS
Female mice were implanted with electrodes for chronic recording of sleep-wake cycles during the entire experimental phase (9, 19, and 29 weeks of age). The disease course was also assessed. At each time-point, blood samples were collected from the orbital plexus to evaluate serum antinuclear antibodies (ANA), which are important serologic parameters of disease evolution. Pain perception was also evaluated.


RESULTS
During the dark phase, (NZB/NZW)F, mice aged 19 weeks spent more time in sleep, and, as a consequence, the total waking time was lower when compared with earlier periods. An augmented number of sleep-stage transitions and microarousals were observed at the 29th week of life in both light and dark phases. At this same time-point, the mice showed lower pain thresholds than they had at 9 weeks of life. The disease status was confirmed; the entire group of mice at 29 weeks of life showed positive ANA with high titer levels.


CONCLUSIONS
The sleep-recording data showed that, during the progress and severe phases of the disease (19 and 29 wks of age, respectively), sleep architecture is altered. According to these results, increased sleep fragmentation, disease activity, and pain sensitivity are features observed in these mice, similar to symptoms of SLE.
Palma
Beatriz Duarte
BD
Department of Psychobiology, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil. biapalma@uol.com.br
Tufik
Sergio
S
D000818:Animals; D000974:Antibodies, Antinuclear / Q000097:blood; D002940:Circadian Rhythm / Q000502:physiology*; D004195:Disease Models, Animal; D005260:Female; D008180:Lupus Erythematosus, Systemic / Q000150:complications* / Q000503:physiopathology* / Q000523:psychology; D008297:Male; D051379:Mice; D008814:Mice, Inbred NZB; D017288:Pain Threshold; D012307:Risk Factors; D012892:Sleep Deprivation / Q000097:blood / Q000150:complications* / Q000503:physiopathology; D013997:Time Factors
D000974:Antibodies, Antinuclear