胎猪肾脏发育不同时期相关信号分子的表达

Expression of related signaling molecules at different stages of kidney development in fetal pig

目的:明确不同时期胎猪的肾脏发育情况,并研究胎猪肾脏发育相关信号分子的表达。方法:收集不同时期(妊娠21.5、27.5、35.0、45.0、75.0及110.0 d)胎猪肾脏组织,应用HE法观察不同时期胎猪肾脏的组织结构。通过实时荧光定量PCR和Western blot分别检测肾脏发育相关信号分子(Pax2、Pax8、Six2、Six1、Sall1和Bmp4)的mRNA和蛋白表达水平,并通过免疫组织化学检测Pax2在不同时期胎猪肾脏的表达定位情况。结果:27.5 d胎猪的后肾已经开始发育;35 d早期肾小体已经出现,肾小管也开始发育;45 d观察到近皮质不成熟的肾小体和近髓质成熟的肾小体;75 d肾单位数目显著增加,观察到肾椎体、肾乳头和肾盂;110d肾脏基本发育成熟,皮髓质分界明显,仍有新的肾单位产生。Pax2、Pax8、Six2、Six1、Sall1和Bmp4在胎猪75d的肾脏中mRNA和蛋白表达量高于35 d。Pax2广泛表达于输尿管芽、后肾间充质、帽状间充质、肾小囊体、逗号形体、S形体以及肾小管,并在后肾发育过程中持续表达。结论:27.5 d时胎猪后肾已经开始发育,110 d基本发育成熟。Pax2、Pax8、Six2、Six1、Sall1和Bmp4等信号分子在胎猪肾脏发育过程中均有不同程度表达,其中Pax2可能是胎猪肾脏发育的关键调控分子。

Objective:To clarify the developmental status of porcine fetal kidney at different stages,and to study the expression of signaling molecules related to the development of porcine fetal kidney.Methods:The kidney tissues of porcine fetuses at different stages(fetuses on post-implantation days 21.5,27.5,35.0,45.0,75.0 and 110.0)were collected.The histological structure of pig fetal kidneys was observed by HE staining.The mRNA and protein expression levels of factors related to renal development signaling molecules(Pax2,Pax8,Six2,Six1,Sall1 and Bmp4)were detected by quantitative real-time PCR(qPCR)and Western blot,respectively.The expression and localization of Pax2 at different stages of fetal kidney were detected by immunohistochemistry.Results:The metanephros of fetal pig initiated its development starting by the 27.5 thday.The early renal corpuscles appeared on the35 thday,and the renal tubules began to develop.On the 45 thday,the immature glomeruli in the cortex region and the proximal matured renal corpuscles in the medulla region could be detected.The number of nephrons on the 75 thday increased significantly,and kidney pyramid,renal papillae and renal pelvis were observed at this stage.On the 110 thday,kidney was basically mature,the cortex and medulla could be distinguished clearly,and new nephrons kept to be produced.The mRNA and protein expression levels of Pax2,Pax8,Six2,Six1,Sall1 and Bmp4 on 75 d were higher than that on 35 d.Pax2 was widely expressed in ureteric bud,metanephric mesenchyme,cap mesenchyme,renal vesicles,comma-shaped bodies,S-shaped bodies and renal tubule,and is continuously expressed during the development of the metanephros.Conclusion:The development of metanephros of fetal pig starts the 27.5 thday and basically reaches maturation on the 110 thday.The signaling molecules such as Pax2,Pax8,Six2,Six1,Sall1 and Bmp4 were expressed along different stages during the kidney development,and Pax2 may be a key regulator of porcine fetal kidney development.