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: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=681099
• 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

该研究计划的远距离目标是提高我们对控制乳腺互动控制的生物学过程的了解，并开发经济可行且消费者可接受的技术或实践，以改善哺乳期持久性并在奶牛中实现更长的泌乳。延长的泌乳将减少牛早期哺乳期花费的比例，因此，与这一时期有关的疾病，代谢障碍和繁殖失败的发生。最近在我的实验室进行的工作表明，与认为的激素催乳素（PRL）相反，在乳制反刍动物中是半乳突的。如果PRL的基础水平与牛奶产量水平没有明确相关，则在啮齿动物的乳腺中，挤奶引起的PRL释放与PRL的牛奶产量抗凋亡效应相关，因此，我们发现在PRL分泌抑制PRL分泌的牛腺体中有更多的凋亡。因此，PRL（尤其是挤奶引起的PRL）可能是通过限制细胞丧失和维持细胞分化来实现泌乳持久性的重要因素。但是，我们还发现，PRL的半乳突作用是通过尚待阐明的机制在乳腺水平上调节的。 ****我的假设是：*** - 挤奶引起的激素释放对于维持乳腺上皮细胞的差异化，分泌活动和存活至关重要。挤奶引起的PRL *** 2-确定局部因素影响泌乳持久性的机制。*** 3-确定系统因素影响泌乳持久性的机制