通草增加哺乳期乳汁分泌的机制研究

摘要

Objective To explore the mechanism of lactogenic effect of Medulla Tetrapanacis in lactation, and investigate the effect of Medulla Tetrapanacis on the composition of latex. Methods Sixteen ICR dams were divided into negative control group ( n = 8) and Medulla Tetrapanacis treatment group ( n = 8) after delivery. Intragaslric administration of 0.25 mL Medulla Tetrapanacis extract of dams was conducted daily in Medulla Tetrapanacis treatment group, and the same amount of normal saline was given in negative control group. The amount of latex and the contents of protein and lactose in latex were compared between two groups, and serum prolactin levels of mice were measured by ELISA. Mouse HC11 mammary epithelial cells were treated by different doses of Medulla Tetrapanacis extract (low dose Medulla Tetrapanacis treatment group, high dose Medulla Tetrapanacis treatment group and control group), fluorescent quantitative RT-PCR was employed to detect the expression of β-casein and lactalbumin mRNA in mammary epithelial cells, and the expression of β-casein, STAT5 protein and phosphorylated STAT5 protein was determined by Western blotting. Results The amount of latex on the 1st, 3rd,8th, 13th and 18th day of lactation in Medulla Tetrapanacis treatment group was higher than that in negative control group. The mass concentration of protein in latex of mice in Medulla Tetrapanacis treatment group (119. 567μg/mL) was significantly higher than that in negative control group (100. 562 μg/mL) (P <0.05), while the concentration of lactose in Medulla Tetrapanacis treatment group (53.072 mmol/L) was significantly lower than that in negative control group (63.290 mmol/L) [P <0.05]. There was no significant difference in the prolactin levels on the 1st, 3rd, 8th and 13th day of lactation between Medulla Tetrapanacis treatment group and negative control group (P >0.05). The expression of β.-casein and lactalbumin mRNA in mammary epithelial cells in low dose Medulla Tetrapanacis treatment group and high dose Medulla Tetrapanacis treatment group was higher than that in control group. The expression of phosphorylated STAT5 protein in mammary epithelial cells was the lowest in control group, and that was the highest in high dose Medulla Tetrapanacis treatment group. Conclusion Medulla Tetrapanacis can increase the phosphorylation of STAT5 protein and promote the prolactin signaling transduction in mammary epithelial cells, which results in the increase of latex amount and protein content.%目的 初步探讨通草在哺乳期增加乳汁分泌的途径和作用机制及其对乳汁成分的影响.方法 将16只产后ICR母鼠分为阴性对照组(n=8)和通草处理组(n=8)；通草处理组每日通过灌胃方式给予母鼠通草提取液0.25 mL,阴性对照组给予等量生理盐水.比较通草处理组与阴性对照组小鼠的泌乳量、乳汁中蛋白质和乳糖含量；采用ELISA法检测小鼠血清中催乳激素的水平.采用不同剂量通草提纯液处理小鼠HC11乳腺上皮细胞(设为低剂量通草处理组和高剂量通草处理组,另设对照组)；采用荧光定量RT-PCR方法检测乳腺上皮细胞中β-酪蛋白和乳清蛋白mRNA的表达；采用Western blotting技术检测乳腺上皮细胞中β-酪蛋白、STAT5蛋白和磷酸化STAT5蛋白的表达.结果 通草处理组小鼠在哺乳第1、3、8、13和18天的泌乳量均高于阴性对照组.通草处理组母鼠乳汁中蛋白质的质量浓度(119.567 μg/mL)明显高于阴性对照组(100.562 μg/mL),乳糖浓度(53.072 mmol/L)明显低于阴性对照组(63.290 mmol/L),差异均有统计学意义(P＜0.05).在哺乳第1、3、8和13天,通草处理组催乳激素水平与阴性对照组比较,差异无统计学意义(P＞0.05).低剂量通草处理组和高剂量通草处理组乳腺上皮细胞中β-酪蛋白及乳清蛋白mRNA的表达均高于对照组.对照组、通草低剂量处理组和通草高剂量处理组乳腺上皮细胞中磷酸化STAT5蛋白的表达水平依次升高.结论 通草可以增加STAT5蛋白的磷酸化水平,加强细胞内信号转导,促进乳腺细胞泌乳,增加乳汁中乳蛋白的含量.