SIRT1/NOX1 pathway mediated ameliorative effects of rosmarinic acid in folic acid-induced renal injury

Abstract

Background and purpose: Renal injury is a serious disorder that can be caused by some diseases or agents. Rosmarinic acid (RA) is a natural and safe compound with powerful antioxidant and anti-inflammatory properties. In this study, the ameliorative effects of RA were assayed in folic acid (FA)-induced renal injury by involving the SIRT1/NOX1 pathway.

Experimental approach: Thirty-six male C57/BL6 mice were divided into 6 groups (n = 6) including control, vehicle, FA, RA, FA + RA 50, and FA + RA 100. After 10 days, blood urea nitrogen (BUN), creatinine, and oxidative stress were measured. The expression of SIRT1 and NOX1 proteins was evaluated by western blot. Also, histopathological alterations were assayed by H&E and PAS staining methods.

Findings/results: BUN and creatinine were significantly higher in the FA group compared to the control group; however, their levels decreased after RA treatment in both doses. A significant decrease was observed in swelling, necrosis, and desquamation of tubular epithelial cells in the FA + RA 50 and FA + RA 100 groups compared to the FA group. RA in the animals receiving FA increased SIRT1 expression and the levels of GSH and SOD compared to the FA group. RA in the animals receiving FA showed a significant decrease in NOX1 expression and MDA level compared to the FA group.

Conclusion and implications: The findings declared that the administration of RA has positive effects against renal damage induced by FA. The effect might result from involvement in the SIRT1/NOX1 pathway and thereby attenuation of oxidative stress.

Keywords: Folic acid; NOX1; Renal failure; Rosmarinic acid; SIRT1.

Fig. 1

The effect of RA (50 and 100 mg/kg) on the serum levels of (A) BUN and (B) creatinine in FA-induced renal injury. The vehicle group received NaHCO3 as FA solvent. FA group received a single dose of FA (250 mg/Kg). Data were expressed as mean ± SEM, n = 6. ^**P ≤ 0.01 indicates a significant difference as compared to the control, vehicle, and RA groups; ^#P ≤ 0.05 and ^##P ≤ 0.01 versus the FA group. FA, Folic acid; RA, rosmarinic acid; NaHCO3, sodium bicarbonate; BUN, blood urea nitrogen.

Fig 2

The RA effect (50 and 100 mg/kg) on renal tissue (hematoxylin and eosin) in FA-induced renal injury. (A) The images of renal tissue with magnification 400× and (B) the tubular diameter in all experimental groups. The vehicle group received NaHCO3 as FA solvent. FA group received a single dose of FA (250 mg/Kg). Data were expressed as mean ± SEM, n = 6. ^***P ≤ 0.001 indicates a significant difference compared to the control, vehicle, and RA groups; ^###P ≤ 0.001 versus FA group. G, glomerulus; D, distal tubules; P, proximal tubules; Di, dilated renal tubules; BM, tubular basement membranes; yellow arrowheads, disseminated epithelial cells; black arrows, detached tubular cells; N, tubular necrosis; S, swollen tubular cells; red arrows, pyknotic nuclei; oval circle, infiltrations of mononuclear cells; FA, folic acid; RA, rosmarinic acid; NaHCO3, sodium bicarbonate.

Fig 3

The effect of RA (50 and 100 mg/kg) on renal tissue stained by PAS staining (magnification 400×) in FA-induced renal injury. The vehicle group received NaHCO3 as FA solvent. FA group received the single dose of FA (250 mg/Kg). G, Glomerulus; D, distal tubules; P, proximal tubules; Di, dilated renal tubules; red arrow, tubular basement membranes; FA, folic acid; RA, rosmarinic acid; NaHCO3, sodium bicarbonate; PAS, periodic acid-Schiff.

Fig 4

The RA effect (50 and 100 mg/kg) on the expression of renal SIRT1 and NOX1 in FA-induced renal injury. (A) A, the bands of western blotting; (B) and (C) the expression of SIRT1 and NOX1proteins, respectively. The vehicle group received NaHCO3 as FA solvent. FA group received a single dose of FA (250 mg/Kg). The data were presented in mean ± SEM, n = 6. ^*P ≤ 0.05 indicates a significant difference compared to the control, vehicle, and RA groups; ^#P ≤ 0.05 and ^###P ≤ 0.001 versus FA group. FA, Folic acid; RA, rosmarinic acid; NaHCO3, sodium bicarbonate.

Fig. 5

The RA effect (50 and 100 mg/kg) on (A) MDA concentration; (B) SOD enzyme activity; (C) GSH concentration in the kidney tissue in FA-induced renal injury. The vehicle group received NaHCO3 as FA solvent. FA group received a single dose of FA (250 mg/Kg). The data were presented in mean ± SEM, n = 6. ^*P ≤ 0.05 indicates significant difference compared to the control, vehicle, and RA groups; ^#P ≤ 0.05 and ^##P ≤ 0.01 versus FA group. FA, Folic acid; RA, rosmarinic acid, NaHCO3; sodium bicarbonate; MDA, malondialdehyde; SOD, superoxide dismutase; GSH, glutathione.