Histological Study On Age-Associated Changes In The Kidney Of The Yak

This experiment was conducted to investigate histological characteristics of age-related changes in yak kidney and expression and localization of kidney related factors.The newborn(1-7 days old,n=5),adult(3-6 years old,n=5)and old(7-10years old,n=5)yaks were selected as the subjects,and Histological methods were used to compare the structure characteristics in the kidney of yaks.The immunohistochemistry method was used to observe the expression and localization of EGFR,BMP-2 and p53 in the kidney of different ages,and the relevant data of nephrons and optical density value were measured by the image analysis software.Histological observations showed that yak kidneys consisted of the surface of the membrane and the internal substance.The malpighian corpuscles were composed of glomeruli and renal capsules.The wall of the renal capsule was rich in collagen fibers and the basal membrane of malpighian corpuscles was PAS positive.The kidney tubules included proximal tubules and distal tubules,which are rich in collagen fibers and had a positive PAS on the epithelium basal membrane.Immunohistochemical results showed that EGFR,BMP-2 positive reaction in the newborn group was mainly distributed in the proximal tubule epithelial cells,and was widely distributed in the adult and old groups.However,the p53 positive reaction was widely distributed from the newborn,adult and old groups.The results of measuring showed that the number of glomeruli per unit field(2.3×10~6μm~2)decreased with age;while the number of glomerular cells and the size of glomerular nuclei increased with age;the differences was in the maximum cross-sectional area of glomeruli and malpighian corpuscle were the largest in adult,followed by the differences in the aged,with those in the newborn being the smallest.In addition,with the age,the trend of changes in the number of tubule epithelial cells in the kidney cortex and medulla per unit vision(2.3×10~4μm~2)and the size of proximal tubule and distal tubule epithelial nuclei were the same as the number of glomeruli and cells in glomeruli,the size of glomeruli nuclei,and themaximum cross-sectional area changes of glomeruli and malpighian corpuscle.The results suggest that the histological structures of yak kidney change with the increase of age.Moreover,it is presumed that the contributing factors to this change might include glomeruli sclerosis and reduction of substantial cells.EGFR and BMP-2 had the effect of promoting kidney development.However,p53 had been widely distributed in newborn kidney of the yaks.It is suggested that p53 had been involved in cell migration and metabolic differentiation and self-renewal in the new stage.