Abstract

Folic acid (FA) is known to be an important micronutrient in humans; however, information regarding the effect of FA supplementation on bovine mammary epithelial (BME) cells is insufficient. FA supplementation is reported to increase milk production in dairy cows, but the underlying molecular mechanisms are unknown. This study examined the effects of FA supplementation on the proliferation and apoptosis of a BME cell line (MAC-T). MAC-T cells were treated with various concentrations (deficient in FA (DF) < 0.01 ng/mL; low-level FA (LF) 3.1 ng/mL; normal FA (NF) 15.4 ng/mL; and high-level FA (HF) 30.8 ng/mL) based on serum folate (10–20 ng/mL) in milking cows. HF treatment significantly increased the proliferation of MAC-T cells. Cellular apoptosis was observed mainly in the DF group. The number of apoptotic cells in DF media was significantly higher than that in NF media. The bcl-2/bax mRNA expression ratio was significantly increased in the HF group compared to that in the DF group. FA supplementation significantly increased the ratio of Bcl-2/Bax protein levels in MAC-T cells. FA supplementation increases proliferation and decreases apoptosis in these cells. This study might provide information regarding the molecular mechanism through which FA supplementation is associated with increased milk yield.

摘要

众所周知，叶酸 (FA) 是人体重要的微量营养素；然而，关于补充 FA 对牛乳腺上皮 (BME) 细胞影响的信息不充分。据报道，补充 FA 可增加奶牛的产奶量，但潜在的分子机制尚不清楚。本研究检查了补充 FA 对 BME 细胞系 (MAC-T) 增殖和凋亡的影响。MAC-T 细胞用不同浓度（缺乏 FA (DF) < 0.01 ng/mL；低水平 FA (LF) 3.1 ng/mL；正常 FA (NF) 15.4 ng/mL；和高水平 FA（ HF) 30.8 ng/mL) 基于挤奶牛的血清叶酸 (10–20 ng/mL)。HF处理显着增加了MAC-T细胞的增殖。细胞凋亡主要在DF组中观察到。DF培养基中凋亡细胞的数量明显高于NF培养基。这与DF组相比，HF组bcl-2 / bax mRNA表达比显着增加。FA 补充剂显着增加了 MAC-T 细胞中 Bcl-2/Bax 蛋白水平的比率。补充 FA 可增加这些细胞的增殖并减少细胞凋亡。这项研究可能会提供有关补充 FA 与增加产奶量相关的分子机制的信息。