Effects of aminoglycosides on glomerular ultrastructure

Area of Science:

• Nephrology
• Pharmacology
• Cell Biology

Background:

• Aminoglycosides are widely used antibiotics.
• Some aminoglycosides can cause kidney damage (nephrotoxicity).
• The precise ultrastructural changes in the kidney glomerulus due to these drugs are not fully understood.

Purpose of the Study:

• To investigate the effects of gentamicin, netilmicin, and tobramycin on rat glomerular ultrastructure.
• To correlate observed ultrastructural changes with potential nephrotoxicity.

Main Methods:

• Male Wistar rats were treated with specific doses of gentamicin, netilmicin, or tobramycin via intraperitoneal injection for seven days.
• Glomerular ultrastructure was examined using both scanning electron microscopy (SEM) and transmission electron microscopy (TEM).

Main Results:

• Gentamicin and tobramycin significantly decreased the number and density of fenestrae in glomerular capillary endothelial cells, observed via TEM and SEM.
• These two drugs also reduced the number of granulated myoepithelioid cells in the juxtaglomerular apparatus.
• Netilmicin did not induce any significant changes in glomerular ultrastructure.

Conclusions:

• Nephrotoxic aminoglycosides, gentamicin and tobramycin, alter the ultrastructure of glomerular capillary endothelium.
• These alterations, particularly the reduction in fenestrae, may explain the impaired glomerular permeability observed with these drugs.