BALB/c Tipi Fare Embriyolarında Gelişen Nefronda Juxtaglomerular Aparatus Hücrelerinin Farklılaşmaları

Abstract

Objective: This study examined the development of nephrons and the differentiation of juxtaglomerular apparatus (JGA) cells in BALB/c type mouse embryos. Thick and thin epon sections were investigated by light microscopy (LM) and transmission electron microscopy (TEM) respectively.
 Materials and Methods: Nephron development is completed by passing through the nephrogenic vesicles in the respected stages of comma shape body, S-shape body, precapillary, immature glomerular, and mature glomerular stage. JGA is distinguished in the mature glomerular stage of nephron development at LM level. According to TEM observations, signs of differentiation of juxtaglomerular (JG) cells and macula densa (MD) cells forming JGA are seen earlier, in precapillary stage. In developed Golgi fields that characterize JG cells, large number of electron lucent small vesicles and small number of electron dense large renin granules are seen in the precapillary stage. In the mature glomerulus, the number of electron dense large granules increases in JG cells. The differentiation of MD cells is indicated by the formation of primary cilia on their apical faces in precapillary stage. Deep membrane folds are formed in the basal and lateral faces of MD cells in the mature glomerular stage. There are many numbers of large mitochondria in these regions.
 Results: JG and MD cells, which play an absolute role in the regulation of the renin-angiotensin system are differentiated in precapillary stage before completion of nephron development and formation of blood vessels.
 Conclusion: Such early differentiation of JGA cells suggests that the renin-angiotensin system is important both in the development of the kidney and in the total development of embryo.