限饲对初情期小鼠乳腺发育的影响及机制

郑吉松; 陈双; 杨强; 张静; 袁聪; 朱晓彤; 束刚; 王丽娜; 高萍; 江青艳; 王松波

doi:10.7671/j.issn.1001-411X.201904036

限饲对初情期小鼠乳腺发育的影响及机制

Effects of feed restriction on mammary gland development of pubertal mice and the involved mechanisms

摘要

摘要:
目的研究限饲对初情期小鼠乳腺发育的影响及机制，为动物乳腺发育的营养调控提供科学依据。

方法选用24只4周龄C57BL/6雌性小鼠，分为对照组和限饲组。试验为期4周，每周称体质量并统计采食量和饮水量，在试验结束前对小鼠进行体成像和体组成检测。试验结束后采集小鼠乳腺并称质量。采集血液，测定血清中胰岛素样生长因子(IGF-1)和雌二醇(E2)的水平。采用Whole-mount染色观察小鼠乳腺发育情况，统计小鼠乳腺终末乳芽(TEB)和导管分支数量。利用免疫荧光染色检测乳腺组织中增殖细胞核抗原(PCNA)的表达。

结果限饲组小鼠体质量、体增质量、平均日采食量、平均日能量摄入均极显著低于对照组(P<0.001)，但其饮水量显著高于对照组(P<0.05)。限饲对小鼠肌肉含量和脂肪含量无显著影响。限饲使小鼠的乳腺质量降低了29%(P<0.05)，对乳腺指数无显著影响。Whole-mount染色结果表明，限饲显著抑制初情期小鼠的乳腺发育，其乳腺组织的TEB数量和导管分支数量均显著低于对照组(P<0.05)。此外，限饲对血清中E2水平无显著影响，但使血清中IGF-1水平降低了34%(P<0.05)。限饲显著抑制了小鼠乳腺组织中PCNA蛋白的表达。

结论限饲可显著抑制初情期小鼠乳腺发育，这可能与限饲可降低血清中IGF-1水平和乳腺组织中增殖相关蛋白PCNA表达有关。

Abstract:
Objective To investigate the effect of feed restriction on mammary gland development of pubertal mice and explore the involved mechanisms, and provide a scientific basis for nutritional regulation during mammary gland development of animals.

Method Twenty-four 4-week-old C57BL/6J female mice were randomly divided into the control group and feed restriction group. The trial lasted for four weeks. The body weight, feed intake and water intake were recorded weekly, and the body imaging and body composition of mice were examined before the end of the trial. At the end of the trial, the mouse mammary gland was collected and weighed. The blood was collected and the levels of insulin-like growth factor (IGF-1) and estradiol (E2) in serum were measured. The mammary gland development was observed and assessed by using whole-mount staining and the numbers of mammary gland terminal end bud (TEB) and duct branches were analyzed. Immunofluorescence staining was used to detect the expression of proliferating cell nuclear antigen (PCNA) in the mammary gland tissue of pubertal mice.

Result The body weight, body weight gain, average daily feed intake and average daily energy intake of mice in feed restriction group were significantly lower than those of mice in control group (P<0.001), while the water intake of feed restriction group was significantly higher than that of control group (P<0.05). Feed restriction had no effect on muscle and fat contents. In addition, feed restriction significantly decreased the mammary gland weight by 29%(P<0.05), with no effect on mammary gland index. The results of whole-mount staining showed that feed restriction significantly inhibited the development of mammary gland, with significant lower number of TEB and duct branches (P<0.05). Furthermore, feed restriction significantly reduced the serum level of IGF-1 by 34%(P<0.05), with no influence on serum E2 level. Feed restriction significantly inhibited PCNA protein expression in the mammary gland of pubertal mice.

Conclusion Feed restriction significantly inhibits mammary gland development of pubertal mice, which might be associated with the decreased level of IGF-1 in serum and expression of proliferation-associated protein PCNA in mammary gland tissue.

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