Transcriptome of normal mammary glands of Sprague-Dawley rats at six stages of development: pre-pubertal, peri-pubertal, pubertal, lactation, adult parous and age-matched nulliparous. Rattus norvegicus

There is a lack of systematic investigations of large-scale transcriptome patterns associated with normal breast development. Herein, we profiled whole-transcriptome (by microarrays) of normal mammary glands in female Sprague-Dawley rats, an animal model widely used in breast cancer research, across six distinctive developmental stages – pre-pubertal, peri-pubertal, pubertal, lactation, and adult parous and age-matched nulliparous. Overall design: Female Sprague-Dawley rats examined in this study are part of controls for a study on effects of environmental chemicals on developing mammary glands. These rats were regularly gavaged with olive oil by gastric intubation, the vehicle for chemical treatment in the parent study. Animals were sacrificed at six developmental time-points reflective of distinct stages of mammary gland development – pre-pubertal (n=10), peri-pubertal (n=5), pubertal (n=5), lactation (n=3), adult parous (n=5) and age-matched nulliparous (n=5). Pre-pubertal animals were sacrificed at postnatal day (PND) 21, peri-pubertal group at PND 42 and pubertal group at PND 63. Animals in the lactation group were sacrificed at the end of lactation at lactating day 28 (PND 146). Parous and age-matched nulliparous animals were sacrificed at PND 181.

目前针对与正常乳腺发育相关的大规模转录组模式，尚缺乏系统性研究。本研究以广泛应用于乳腺癌研究的动物模型——雌性斯普拉格-道利（Sprague-Dawley, SD）大鼠为对象，采用微阵列（microarrays）技术对其正常乳腺组织开展全转录组（whole-transcriptome）分析，覆盖六大典型发育阶段：青春期前、青春期前后、青春期、泌乳期、成年经产及同年龄未产状态。

实验设计概述：本研究纳入的雌性斯普拉格-道利大鼠，为一项探究环境化学物对发育中乳腺影响的对照队列。该队列大鼠通过胃插管法定期灌胃给予橄榄油——该物质为母体研究中化学处理的溶剂载体。实验按六个对应乳腺发育不同阶段的时间节点对大鼠实施安乐死：青春期前（n=10）、青春期前后（n=5）、青春期（n=5）、泌乳期（n=3）、成年经产（n=5）及同年龄未产（n=5）。其中，青春期前大鼠于出生后第21天（postnatal day 21，缩写为PND 21）安乐死；青春期前后组于PND 42、青春期组于PND 63安乐死；泌乳期组于泌乳第28天（PND 146，即出生后第146天）泌乳结束时实施安乐死；成年经产及同年龄未产组均于PND 181实施安乐死。