Departamento de Psicobiologia, Universidade Federal de São Paulo, Escola Paulista de Medicina (UNIFESP/EPM), São Paulo, SP, Brazil.
Eur J Pain. 2011 Jul;15(6):545-53. doi: 10.1016/j.ejpain.2010.10.009. Epub 2011 Jan 26.
Osteoarthritis (OA) is a major healthcare burden with increasing incidence, and is characterised by the degeneration of articular cartilage. OA is associated with chronic pain and sleep disturbance.
The current study examined and compared the long-term effects of chronic articular pain on sleep patterns between female and male rats in an experimental model of OA.
Rats were implanted with electrodes for electrocorticography and electromyography and assigned to control, sham or OA groups. OA was induced by the intra-articular administration of (2 mg) monosodium iodoacetate into the left knee joint in male and female rats (at estrus and diestrus phases).
Sleep was monitored at days 1, 10, 15, 20 and 28 after iodoacetate injection during light and dark periods. The results showed that the overall sleep architecture changed in both sexes. These alterations occurred during the light and dark periods, began on D1 and persisted until the end of the study. OA rats, regardless of sex, showed a fragmented sleep pattern with reduced sleep efficiency, slow-wave sleep and paradoxical sleep, and fewer paradoxical sleep bouts. However, the males showed lower sleep efficiency and reduced slow-wave sleep compared to females during the dark period. Additionally, OA affected the hormonal levels in male rats, as testosterone levels were reduced in comparison to the control and sham groups. In females, progesterone and estradiol remained unchanged throughout the study.
Our results suggest that the chronic model of OA influenced the sleep patterns in both sexes. However, males appeared to be more affected.
骨关节炎（OA）是一种发病率不断增加的主要医疗保健负担，其特征是关节软骨退化。OA 与慢性疼痛和睡眠障碍有关。
本研究在 OA 的实验模型中，检查和比较了慢性关节疼痛对雌性和雄性大鼠睡眠模式的长期影响。
大鼠被植入脑电图和肌电图电极，并被分配到对照组、假手术组或 OA 组。雄性和雌性大鼠（发情期和间情期）的左膝关节内注射（2 mg）单碘乙酸钠诱导 OA。
在碘乙酸盐注射后的第 1、10、15、20 和 28 天，在白天和黑夜监测睡眠。结果表明，两种性别整体睡眠结构都发生了变化。这些变化发生在白天和黑夜，从第 1 天开始，并持续到研究结束。OA 大鼠，无论性别如何，都表现出睡眠碎片化，睡眠效率降低，慢波睡眠和异相睡眠减少，异相睡眠发作减少。然而，与雌性相比，雄性在夜间的睡眠效率更低，慢波睡眠更少。此外，OA 影响了雄性大鼠的激素水平，因为与对照组和假手术组相比，睾酮水平降低。在雌性中，孕激素和雌二醇在整个研究过程中保持不变。
我们的结果表明，慢性 OA 模型影响了两种性别的睡眠模式，但雄性似乎受到的影响更大。
