Gentamicin and tobramycin nephrotoxicity. A morphologic and functional comparison in the rat

Area of Science:

• Nephrology
• Pharmacology
• Toxicology

Background:

• Aminoglycosides like gentamicin and tobramycin are crucial antibiotics.
• Nephrotoxicity is a significant concern with aminoglycoside use.

Purpose of the Study:

• To compare the nephrotoxic effects of gentamicin and tobramycin in a rat model.
• To investigate the dose-dependent and time-dependent renal injury caused by these antibiotics.

Main Methods:

• Fischer 344 rats were administered varying doses of gentamicin and tobramycin.
• Renal function was assessed via serum creatinine and blood urea nitrogen (BUN) levels.
• Kidney tissues were analyzed using light and electron microscopy.

Main Results:

• Gentamicin induced progressive renal proximal tubular necrosis, with elevated BUN and creatinine levels.
• Tobramycin, even at higher doses, caused only minimal tubular damage and slight increases in BUN and creatinine.
• Ultrastructural changes in tobramycin-treated rats mirrored gentamicin-induced changes but were less severe and appeared later.

Conclusions:

• Tobramycin is significantly less nephrotoxic than gentamicin in this experimental model.
• The mechanism of renal injury for both drugs appears similar.
• Tobramycin represents a potentially safer alternative for antibiotic therapy where aminoglycosides are indicated.