Quantification of PAS reactive materials in the renal cortices of rat and mouse

Abstract

The purpose of this study was_to quantify any age-related changes in PAS reactivi-ty in the renal cortex of ~ndiseased rat and mouse kidneys, and to apply statistical analysis (Student's t-Test) to the data obtained to determine (1) ·intraspecific PAS reactivity changes with age and (2) interspecific PAS.reactivity relationships within four relative age g.roups. The kidneys were removed, longitudinally divided at the hilus, fixed with a solution of ethanol: formalin: acetic acid (AFA), and embedded inparaffin. Sections 1011 in thickness were mounted and stained utilizing routinePAS·procedures. Significant differences were found between age groups within each species, with both rat and mouse exhibit_ing a. peak of PAS reactivity. in a ~iddle ag_e group, with significantly lower reactivity,in the younger and older age groups. The interspecific relationships wer_e· significantly different when identical areas (8 X 104 ]1 2 ) of cortex were compared. In order to cqmpare interspecific tubular ·PAS rea~tive relationships, the number of tubules per area within each age_ group~of each species was determined. No significant intraspecific,. changes in tubules perJarea .occurred with age in either species, but the mouse had significantly more tubules per area than rat. , This data was applied· to the ·area ·comparison to illustrat_e the more intense PAS reactivity· in rat ·tubular basement membranes and brush borde:r;s when compar~d· with· mouse:. tubular basement membra.nes and. brush borders.