Carvalho Ana Laura O, Ferri Bárbara G, de Sousa Francielly A Lopes, Vilela Fabiana C, Giusti-Paiva Alexandre
Programa Multicêntrico de Pós-Graduação em Ciências Fisiológicas, Sociedade Brasileira de Fisiologia (SBFis), Brazil; Laboratório de Fisiologia Translacional, Departamento de Ciências Fisiológicas, Instituto de Ciências Biomédicas, Universidade Federal de Alfenas-MG, Alfenas, Brazil.
Laboratório de Fisiologia Translacional, Departamento de Ciências Fisiológicas, Instituto de Ciências Biomédicas, Universidade Federal de Alfenas-MG, Alfenas, Brazil.
Int J Dev Neurosci. 2016 Oct;53:75-82. doi: 10.1016/j.ijdevneu.2016.07.005. Epub 2016 Jul 25.
Several studies have investigated the effects of artificial litter size adjustment on offspring development. Social play behavior is important for neurobehavioral development and is impaired in several developmental psychiatric disorders. This study therefore investigated the effect of litter size on play behavior in adolescent rats. On postnatal day (PND) 2, litters were adjusted to a small litter (SL) size of 3 pups per dam or normal litter (NL) size of 12 pups per dam. Maternal behaviors scored daily during the first week of lactation (PND2-8) revealed that arched nursing and pup licking behaviors were increased in dams with SLs versus those with NLs. SL offspring exhibited accelerated weight gain and advanced development of physical landmarks and reflexes, possibly due to overnutrition. Social isolation lasting 3.5h prior to social play behavioral testing produced a higher frequency and duration of pouncing, pinning, sniffing, and grooming in both male and female offspring. However, male SL offspring exhibited a lower frequency of pouncing and pinning when compared with male NL offspring, while no litter size-dependent differences were observed in social behaviors unrelated to play (sniffing and grooming). These findings identify a possible sexually dimorphic influence of litter size in the development of social behavior. Given that social behaviors such as play behavior are vital for normal cognitive and social development, these findings have important implications for developmental and neuropsychiatric research.
多项研究调查了人工调整窝仔数对后代发育的影响。社交玩耍行为对神经行为发育很重要，且在几种发育性精神疾病中会受损。因此，本研究调查了窝仔数对青春期大鼠玩耍行为的影响。在出生后第2天（PND2），将窝仔调整为每只母鼠3只幼崽的小窝（SL）大小或每只母鼠12只幼崽的正常窝（NL）大小。在哺乳期的第一周（PND2 - 8）每天记录的母性行为显示，与NL组母鼠相比，SL组母鼠的弓背哺乳和舔舐幼崽行为增加。SL组后代体重增加加速，身体标志和反射发育提前，这可能是由于营养过剩所致。在社交玩耍行为测试前持续3.5小时的社会隔离使雄性和雌性后代的突袭、压制、嗅探和梳理行为的频率和持续时间更高。然而，与雄性NL组后代相比，雄性SL组后代的突袭和压制频率较低，而在与玩耍无关的社交行为（嗅探和梳理）中未观察到窝仔数依赖性差异。这些发现确定了窝仔数在社交行为发育中可能存在的性别差异影响。鉴于玩耍行为等社交行为对正常认知和社交发育至关重要，这些发现对发育和神经精神研究具有重要意义。
