The impact of gallic acid on the methotrexate-induced kidney damage in rats

Abstract

Prolonged use of an antineoplastic agent methotrexate (MTX), can cause numerous side effects such as nephrotoxicity. The aim of this study was to examine the effects of MTX on kidneys and demonstrate the protective effects of gallic acid (GA). Twenty-four, male, rats distributed into three groups. Each groups consisted eight rats and only saline was administered to the control group. The MTX group received a single dose (20 mg/kg) MTX intraperitoneally. The MTX + GA group received same dose MTX and 100 mg/kg GA orally during the 7 days. Renal functions, oxidative stress markers, histopathological and immunohistochemical changes were evaluated at the end of the experiment. Blood urea nitrogen, creatinine, uric acid levels and tissue oxidative stress markers, total oxidant status and oxidative stress index levels significantly increased and total antioxidant status levels significantly decreased in MTX group compared with the control group. At the histopathological examination hemorrhages, tubular cell necrosis, glomerulosclerosis, inflammatory cell infiltrations and proteinous materials in tubules were noticed in MTX group. Immunohistochemical examination revealed that increased expressions of serum amyloid A (SAA), tumor necrosis factor alpha (TNF-α), prostaglandin E2 (PGE-2) and C-reactive protein (CRP) in tubular epithelial cells of kidneys in this group. There were no immunoreaction with SAA and CRP, only small number of PGE-2 and TNF-α positive tubular epithelial cells were observed in MTX + GA group. In conclusion, all evidence suggested that oxidative stress caused MTX-induced nephrotoxicity and GA prevent the kidney from the nephrotoxicity due to its antioxidant and anti-inflammatory activities.

Keywords: Gallic acid; Methotrexate; Nephrotoxicity; Oxidative stress; Pathology.

Fig. 1

Microscopical findings of the kidneys in MTX group by different magnification. Marked glomerulosclerosis in glomeruli (black arrows), hemorrhages (arrow heads) and proteinous materials in tubules (white arrows), HE, (A) Bar = 200 μm, (B)and (C) Bar = 100 μm, (D) Bar = 50 μm.

Fig. 2

Histopathological examination results of the kidneys. (A): Normal histological appearance of the kidney in a rat belonging the control group, (B): Marked glomerulosclerosis (arrow head) and proteinous material in the lumen of the tubules (arrows), (C): Relatively normal histology of a kidney in a rat from MTX + GA group, HE, Bars = 100 μm.

Fig. 3

CRP immunoreaction in the groups. (A): Negative immunoreaction in a kidney of a rat belonging control group, (B): Marked CRP expression in tubular epithelial cells (arrows) in a rat from MTX treated group, (C): Negative immunoreaction of CRP in a kidney from a rat belonging MTX + GA group, Streptavidin biotin peroxidase method, Bars = 100 μm.

Fig. 4

PGE-2 immunoreaction in the groups. (A): Negative immunoreaction in a kidney of a rat belonging control group, (B): Marked PGE2 expression in numerous proximal tubular epithelium (arrows) in a rat from MTX treated group, (C): PGE2 expression in some tubules (arrows) in a kidney from MTX + GA group, Streptavidin biotin peroxidase method, Bars = 100 μm.

Fig. 5

TNF-α immunoreaction in the groups. (A): Negative immunoreaction in control group, (B): Marked TNF-α expression in proximal tubular epithelium (arrows) in a rat from MTX treated group, (C): Slight immunoreaction in some tubular epithelial cells (arrows) in a kidney from MTX + GA group, Streptavidin biotin peroxidase method, Bars = 100 μm.

Fig. 6

SAA immunoreaction in the groups. (A): Negative immunoreaction in a kidney of a rat belonging control group, (B): Marked SAA expression in proximal tubular epithelium (arrows) in a rat from MTX treated group, (C): Negative immunoreaction in a kidney from MTX + GA group, Streptavidin biotin peroxidase method, Bars = 100 μm.