Morphometry of the Glomerular Tuft During Normal Postnatal Growth in Female Rats. Effects of Age, Location of Glomeruli and Methods of Obtaining and Processing the Renal Tissue

Abstract

Total glomerular filtration rate depends upon the structural integrity, number and area of glomeruli. Counting  the number of glomeruli as well as measuring glomerular area or volume is nowadays widely employed  in human and experimental biology. 

Although functional and morphological differences between superficial and juxtamedullary glomeruli have  been described, this is not always taken into account in morphometric studies. The aim of this paper was to  study in female rats the area of juxtamedullary glomeruli and the area of superficial glomeruli as well as the  influence of the age of rats and the methods of obtaining and processing the renal tissue. 

The glomerular area was larger in kidneys collected in liquid nitrogen and smaller in those fixed in Bouin  (See Materials and Methods); 4% formaldehyde. These results were obtained in superficial and in juxtamedullary  glomeruli (F=29.60, p<0.0001).  Glomerular area increased with time in superficial as well as in juxtamedullary glomeruli (F=9.21,  p<0.0001). 

The area of the juxtamedullary glomeruli was significantly higher (F=329.29, p<0.0001) than that of superficial  glomeruli, independently of the different methods of obtaining and processing renal tissue, or the  age of the animals. 

The results indicate that glomerular area is greater in juxtamedullary glomeruli, increases with age, and  that different methods of obtaining and processing the renal tissue do have influence on glomerular size.