Effects of Toxicity Induced by Gentamicin on the Kidney of Killifish Aphaniops hormuzensis and the Role of Wt1 and MMP9 Genes in Response to This Toxicity

Aminoglycoside antibiotics such as gentamicin are used to cure bacterial infections in humans and other animals, but they can cause nephritic damage, as well. Nephrotoxicity is one of the side effects of gentamicin.

The objective of this study was to investigate the effects of toxicity induced by gentamicin on the kidney of killifish Aphaniops hormuzensis. Also, we aimed to study the expression pattern of Wt1 and MMP9 genes by real-time PCR in response to this toxicity.

First, 10 µg/g (sub-lethal dose) gentamicin was given to adult fish. The kidney tissues were dissected and preserved in 10% formalin for a 24-hour; then, they underwent standard histological procedures. The sections were prepared at 3 μm and stained with Haematoxylin & Eosin (H&E). The slide microphotography process was done by an Olympus CH2 microscope. The RNA was isolated, and cDNA was synthesized with a standard protocol, and the expression patterns of Wt1 and MMP9 genes were examined by real-time PCR.

Nephrotoxicity occurred 10 hours after the injection of gentamicin, and the injury was detected in the epithelium of kidney tubules. The kidney tubule regenerated itself within 10 days post-injection (dpi). On 7 dpi, the nephrogenic body formation occurred and was differentiated into renal nephrons. The Wt1 gene was upregulated (two-fold) on 5 dpi after kidney damage and then had a down-regulation on 7 dpi when the kidney began to regenerate. The MMP9 gene showed increased expression in comparison with the control sample in the study days, and this expression increased on 7 dpi by 6.6 folds.

The results of this study, for the first time, highlighted that nephritic damage appears in the kidney of A. hormuzensis after toxicity induced by gentamicin and that changes in the expression of the examined genes are consistent with their roles in the process of renal regeneration in this species.