【科技日报】海马为何能“雄性怀孕”

Core Viewpoint - The research reveals the unique biological phenomenon of "male pregnancy" in seahorses and their close relatives, uncovering the cellular and molecular mechanisms behind it [3]. Group 1: Mechanism of Male Pregnancy - Male seahorses possess a specialized brood pouch that allows them to carry fertilized eggs, providing protection, oxygen, nutrients, and immune support to the embryos, comparable to mammalian uteri [1]. - The study identified a type of epithelial progenitor cell with stem cell potential that is crucial for the formation of the brood pouch, regulated by male hormones [1][2]. - The brood pouch's inner layer thickens during early pregnancy, forming structures similar to mammalian placentas, and the presence of "trophoblast-like cells" indicates evolutionary adaptations [2]. Group 2: Immune Regulation - Seahorses lack the foxp3 gene, which is essential for immune tolerance in mammals, and have evolved a unique "non-foxp3 dependent" immune regulation mechanism to prevent the paternal immune system from rejecting the embryos [2]. - The study highlights the dynamic balance of immune responses at the maternal-fetal interface, which is critical for successful pregnancy [2]. Group 3: Evolutionary Insights - The research compares different types of brood pouches across seahorse species, suggesting that the evolutionary origin of these structures may stem from specialized epidermal cells that initially helped attach sticky eggs to the male's body [2]. - Over time, these cells evolved to recruit more functionally similar cells, leading to the complexity and diversity of brood pouch structures [2].