Neuroscience Institute, National Research Council of Italy (CNR), Cagliari, Italy.
Department of Life and Environment Sciences, Section of Neuroscience and Anthropology, University of Cagliari, 09100, Cagliari, Italy.
Psychopharmacology (Berl). 2017 Sep;234(17):2587-2596. doi: 10.1007/s00213-017-4661-2. Epub 2017 Jun 16.
Social isolation of rats immediately after weaning is thought to represent an animal model of anxiety-like disorders. Socially isolated virgin females showed a significant decrease in allopregnanolone levels, associated with increased anxiety-related behavior compared with group-housed rats.
The present study investigates whether post-weaning social isolation affects maternal behavior and assesses neuroactive steroid levels in adult female rats during pregnancy and postpartum.
Socially isolated dams displayed a reduction in the frequency of arched back nursing (ABN) behavior compared to group-housed dams. In addition, both total and active nursing were lower in socially isolated dams compared to group-housed dams. Compared to virgin females, pregnancy increases allopregnanolone levels in group-housed as well as isolated dams and such increase was greater in the latter group. Compared to pregnancy levels, allopregnanolone levels decreased after delivery and this decrease was more pronounced in isolated than group-housed dams. Moreover, the fluctuations in plasma corticosterone levels that occur in late pregnancy and during lactation follow a different pattern in socially isolated vs. group-housed rats.
The present results show that social isolation in female rats decreases maternal behavior; this effect is associated with lower allopregnanolone concentrations at postpartum, which may account, at least in part, for the poor maternal care observed in socially isolated dams. In support of this conclusion is the finding that finasteride-treated dams, which display a decrease in plasma allopregnanolone levels, also showed a marked reduction in maternal care, suggesting that allopregnanolone may contribute to the quality of maternal care.
人们认为，断奶后大鼠的社交隔离代表了一种类似焦虑障碍的动物模型。与群居大鼠相比，单独饲养的处女雌性大鼠的别孕烯醇酮水平显著降低，同时伴有焦虑相关行为增加。
本研究调查了断奶后社交隔离是否会影响母性行为，并评估了成年雌性大鼠在怀孕期间和产后的神经活性甾体水平。
与群居对照组相比，社交隔离组的母鼠拱背哺乳（ABN）行为的频率降低。此外，与群居对照组相比，社交隔离组的总哺乳和活跃哺乳次数均较低。与处女雌性大鼠相比，怀孕会增加群居和隔离组的别孕烯醇酮水平，而后者的增加幅度更大。与怀孕水平相比，分娩后别孕烯醇酮水平下降，隔离组比群居组下降更为明显。此外，社交隔离组与群居组相比，血浆皮质酮水平在妊娠晚期和哺乳期的波动呈现出不同的模式。
本研究结果表明，社交隔离会降低雌性大鼠的母性行为；这种影响与产后较低的别孕烯醇酮浓度有关，这至少可以部分解释在社交隔离组中观察到的母性照顾不良的现象。支持这一结论的是，经 finasteride 处理的母鼠，其血浆别孕烯醇酮水平下降，同时也表现出明显的母性照顾减少，这表明别孕烯醇酮可能有助于母性照顾的质量。
