Expression and characterization of anionic components in the tubulointerstitial compartment of rat kidney during polymicrobial sepsis

The aim of the study was to evaluate sialic acids and hyaluronan expression, anionic components important for the structure and function of the renal tubulointerstitial compartment, in the early stages of sepsis. Two groups of rats were used: (1) sham-operated controls; (2) cecal ligation and puncture (CLP) (polymicrobial sepsis model). A search for microbial growth was made in the peritoneal fluid to document infection. Tubular function was evaluated by means of urinary protein loss, urinary Na+ and urea excretion. Kidney samples were processed to analyze histology, sialic acids (lectin histochemistry) and hyaluronan (immunohistochemistry) expression. Results showed increased urinary protein loss and fractional excretion of Na+ and urea reduction in the CLP group. Histological changes, particularly in the cortex and in proximal tubules of the CLP group, were observed. In septic rats, compared to controls, sialic acids decreased in amount and their acetylation increased in the tubules, although to a lesser extent in the proximal portion. Hyaluronan was expressed in the medullary interstitium and in a few areas of cortex in controls. In septic rats it increased in the cortical interstitium and appeared in proximal tubules. These results suggest correlation between expression changes of anionic components and tubulointerstitium morphofunctional alterations during sepsis. A role of these molecules in protection/defense and repair processes may be suggested.