Effects of maternal bilateral ureteral ligation on formation of the glomerular basement membrane in fetal rat kidney.

BACKGROUND

The present study was designed to clarify development of filtration property of fetal renal glomerulus when maternal kidney is dysfunctional.

MATERIALS AND METHODS

Maternal bilateral ureteral ligation was performed on days 17, 19, and 21 of pregnancy. One day after each operation, cationized ferritin (CF), native ferritin (NF), and horseradish peroxidase (HRP) were injected, respectively, in the fetuses. Distribution of the tracers in the fetal kidneys was investigated electron microscopically.

RESULTS

On fetal day 20, clustered CF particles were present in the laminae rarae interna and externa of the glomerular basement membrane of the fetuses from ureter-ligated mothers, while the clusters were arrayed in three to four layers in that of the fetuses from sham-ligated ones. On fetal day 22, a relatively large amount of CF particles was present in the lamina rara externa in the fetuses from ureter-ligated mothers when compared to that in the age-matched control fetuses. On fetal days 20 and 22, the number of NF particles was decreased, and shortening of the time for filtration of HRP through the glomerular basement membrane was observed in the fetuses from the ligated mothers.

CONCLUSIONS

These results suggest that dysfunction of maternal kidneys causes accelerated formation of fetal glomerular basement membrane and stimulates glomerular function in filtration in fetal rat kidney.