Remodeling of mammary tissue and lactation persistency

乳腺组织重塑和泌乳持续性

• 批准号: RGPIN-2017-05427
• 负责人: Lacasse, Pierre
• 金额: $ 1.82万
• 依托单位: Université de Sherbrooke
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=656280
• 关键词: Remodeling; mammary; tissue; lactation; persistency

The long range objectives of this research program are to improve our knowledge of the biological process involved in the control of mammary gland involution and to develop economically viable and consumer acceptable technologies or practices that would improve lactation persistency and enable longer lactation in dairy cows. Extended lactation would reduce the proportion of cow's lifetime spent in early lactation and, thus, the occurrence of disease, metabolic disorder and reproduction failure associated with this period.***Although little is known about the biological control of persistency, factors such as milking frequency, completeness of milk removal, parity, photoperiod, nutrient intake and gestation have been shown to affect it. Recent work carried out in my laboratory, have demonstrated that the hormone prolactin (PRL), contrary to what was believed, is galactopoietic in dairy ruminants. If basal level of PRL was not clearly associated with level of milk production, the milking-induced PRL release was correlated to level of milk production Anti-apoptotic effects of PRL have been reported in the mammary gland of rodents and, accordingly, we found more apoptosis in the glands of cows where PRL secretion was inhibited. Therefore, it is possible that PRL, especially the milking-induced PRL, is an important factor for lactation persistency by limiting the loss of cells and maintaining cell differentiation. However, we also found that the galactopoietic action of PRL is modulated at the level of the mammary gland by a mechanism that remains to be elucidated. ******My hypotheses are:***-The milking-induced release of hormone is important to maintain the differentiation, the secretory activity and the survival of the mammary epithelial cells.***- Several factors affect milk production and lactation persistency by modulating the amount of hormones release at milking and/or mammary gland responsiveness to them.******My short range objectives are:***1- To determine the factors controling the magnitude of milking-induced release of PRL***2- To determine the mechanisms by which local factors affect lactation persistency.***3- To determine the mechanism(s) by which systemic factors affect lactation persistency

该研究计划的长期目标是提高我们对控制乳腺退化的生物过程的了解，并开发经济可行且消费者可接受的技术或实践，以提高泌乳持久性并延长奶牛的泌乳时间。延长泌乳期会减少奶牛在泌乳早期度过​​的一生的比例，从而减少与这一时期相关的疾病、代谢紊乱和繁殖失败的发生。***尽管人们对持久性的生物控制知之甚少，但诸如挤奶频率、排奶完整性、胎次、光周期、营养摄入和妊娠等因素已被证明会对其产生影响。我的实验室最近进行的研究表明，与人们所认为的相反，催乳素（PRL）激素在乳反刍动物中具有泌乳素生成作用。如果PRL的基础水平与产奶量没有明显的相关性，则挤奶引起的PRL释放与产奶量相关。在啮齿类动物的乳腺中已经报道了PRL的抗凋亡作用，因此，我们在PRL分泌受到抑制的奶牛的腺体中发现了更多的细胞凋亡。因此，PRL，尤其是挤奶诱导的PRL，可能通过限制细胞损失和维持细胞分化而成为泌乳持续性的重要因素。然而，我们还发现 PRL 的乳汁生成作用在乳腺水平上受到一种仍有待阐明的机制的调节。 ******我的假设是：***-挤奶诱导的激素释放对于维持乳腺上皮细胞的分化、分泌活性和存活非常重要。***-有几个因素通过调节挤奶时激素释放量和/或乳腺对其的反应来影响产奶量和泌乳持续性。******我的短期目标是：***1-确定控制幅度的因素 泌乳诱导的 PRL 释放***2- 确定局部因素影响泌乳持续性的机制。***3- 确定全身因素影响泌乳持续性的机制