Ultrastructural Study of the Effects of Recombinant Human Growth Hormone on the Rat Renal Tubulointerstitial Following Subtotal (5/6h) Nephrectomy

Compensatory renal growth (CRG) is growth of the remaining functional nephrons and interstitium alter some nephrous have been surgically removed or damaged due to disease. This growth includes the increase of kidney weight caused by hepertrophy and hyperplasia. Although uremic patients are often treated with growth hormone (GH), it is thought that GH may actually increase the degree of renal hypertrophy and the progress of CRG to the scarring and therefore accelerate renal failure. The aim was ultrastructural study of the effects of recombinant human growth hormone (rhGH) on the renal tubulointerstitial changes following 5/6 nephrectomy (SNX).

For this 48 rats from mule Lewis and Dwarf Lewis rats strains were used. Each strain was divided to control, control+rhGH, SNX and SNX+rhGH groups. Dwarf rats strain have only 10% of circulating GH compared to the normal strain one month later the rats were injected with exogenous growth hormone (thGH) or saline two times per day for 30 consecutive days.

The results showed tubular basement membranes was partially thickened in control thGH group and it was too thickened and multi-layered in the SNX groups. Tubular basement membrane was too thickened in the SNX-TGH group in compared to SNX only. Many of Convoluted tubules lost their apical architecture and mitochondria often appeared damaged and cytoplasm contained increased numbers of lysosomes. After SNX areas of focal fibrosis were common. These areas were become infiltrated with modified fibroblasts and myofibroblasts were present. The interstitium become filled with extracellular fibres and amorphous material.

It is evident that many of these changes were made more sever by treatment with thGH in both strains following SNX. So it seems GH caused more synthesis of extracellular matrix proteins and ultrastructural changes of the renal tubulointerstitial.