Ameliorative effect of chrysin on adenine-induced chronic kidney disease in rats

Abstract

Chrysin (5, 7- dihydroxyflavone) is a flavonoid with several pharmacological properties that include antioxidant, anti-inflammatory and antiapoptotic activities. in this work, we investigated some effects of three graded oral doses of chrysin (10, 50 and 250 mg/kg) on kidney structure and function in rats with experimental chronic renal disease (CKD) induced by adenine (0.25% w/w in feed for 35 days), which is known to involve inflammation and oxidative stress. Using several indices in plasma, urine and kidney homogenates, adenine was found to impair kidney function as it lowered creatinine clearance and increased plasma concentrations of creatinine, urea, neutrophil gelatinase-associated lipocalin and N-Acetyl-beta-D-glucosaminidase activity. Furthermore, it raised plasma concentrations of the uremic toxin indoxyl sulfate, some inflammatory cytokines and urinary albumin concentration. Renal morphology was severely damaged and histopathological markers of inflammation and fibrosis were especially increased. In renal homogenates, antioxidant indices, including superoxide dismutase and catalase activities, total antioxidant capacity and reduced glutathione were all adversely affected. Most of these adenine - induced actions were moderately and dose -dependently mitigated by chrysin, especially at the highest dose. Chrysin did not cause any overt adverse effect on the treated rats. The results suggest that different doses of chrysin produce variable salutary effects against adenine-induced CKD in rats, and that, pending further pharmacological and toxicological studies, its usability as a possible ameliorative agent in human CKD should be considered.

Fig 1. Chemical structure of chrysin (5,7 dihydroxy flavone).

Fig 2. Effect of chrysin treatment on creatinine clearance, plasma concentrations of creatinine, urea and neutrophil gelatinase-associated lipocalin (NGAL), urinary albumin concentration and N-acetyl-β-D-glucosaminidase (NAG) activity in control rats and rats treated either singly or concomitantly with either adenine (ADE) or chrysin (C) at doses of 10, 50 or 250 mg/kg.

Each column and vertical bar is a mean ± SEM (n = 6).

Fig 3. Effect of chrysin treatment on either renal concentration or activity of reduced glutathione (GSH), superoxide dismutase (SOD), total antioxidant capacity (TAC) and catalase (CAT) in control rats and rats treated either singly or concomitantly with either adenine (ADE) or chrysin (C) at doses of 10, 50 or 250 mg/kg.

Each column and vertical bar is a mean ± SEM (n = 6).

Fig 4. Effect of chrysin treatment on plasma concentrations of indoxyl sulfate and cystatin in control rats and rats treated either singly or concomitantly with either adenine (ADE) or chrysin (C) at doses of 10, 50 or 250 mg/kg.

Each column and vertical bar is a mean ± SEM (n = 6).

Fig 5. Effect of chrysin treatment on plasma concentrations of the cytokines tumor necrosis factor alpha (TNF α), sclerostin adiponectin, interleukin–one beta (IL-1β) and endothelin in control rats and rats treated either singly or concomitantly with either adenine (ADE) or chrysin (C) at doses of 10, 50 or 250 mg/kg.

Each column and vertical bar is a mean ± SEM (n = 6).

Fig 6. The blot key from left to right in panel A shows both the un-cleaved (37KDa) and cleaved (25KDa) caspase-3 bands in kidney homogenates from rats after their treatment with chrysin 10 mg/kg, chrysin 10 mg/kg + adenine, chrysin 50 mg/kg, chrysin 50 mg/kg + adenine, chrysin 250 mg/kg, chrysin 250 mg/kg + adenine, saline (control), and adenine using Western blot analysis.

The graph in panel B represents the densitometry measurement of both the un-cleaved and cleaved caspase-3 bands in kidney homogenates from all treated and non-treated rats.

Fig 7. Effect of chrysin on adenine-induced morphological changes in the kidney.

Representative pictures of kidney slices of the control group, the adenine group, the chrysin 10mg/kg group and the adenine plus chrysin 10 mg/kg group used for semi-quantitative scoring of inflammation and fibrosis. (A) HE staining used for the identification and semi-quantitative scoring of inflammation. The black slender arrows point to examples of leucocyte infiltration (20-fold magnification). (B) PAS staining, used for the identification and semi-quantitative scoring of atrophy of the basal membrane and dilatations. The white filled arrows point to examples of atrophic basal membranes (20-fold magnification). (C) MT staining, used for identification and semi-quantitative scoring of fibrosis. The black filled arrows point to collagen deposition, characteristic for fibrosis (20-fold magnification).