Intervention effects of curcumin on hepatic oxidative stress injury in water arsenic-exposed rats

Abstract

Objective To observe the effects of curcumin on hepatic oxidant stress in water arsenic-exposed rats and to study its mechanism, which can offer references for curcumin used in antioxidant therapy of arsenic poisoning. Methods Thirty-two SD rats were divided into 4 groups according to body weight by random number table, half male and half female. Including control group (lavaged 135 days with deionized water), arsenic poisoning group(lavaged 45 days with deionized water after lavaging 90 days with 10 mg/kg sodium arsenite), pure curcumin group (lavaged 135 days with 1 000 mg/kg curcumin solution) and curcumin treatment group (lavaged 45 days with 1 000 mg/kg curcumin solution after lavaging 90 days with 10 mg/kg sodium arsenite), 8 rats in each group. The arsenic contents of urine (urine creatinine corrected) and liver were detected by hydride generation inductively coupled plasma optical emission spectrometer (HG-ICP-OES); the activity of Cu/Zn-superoxide dismutase (SOD1) and catalase (CAT), the contents of malondialdehyde (MDA) in serum and liver homogenate by colorimetric method;the protein expression of liver antioxidant enzyme(SOD1 and CAT) was assayed by Western blotting. Results The arsenic contents of urine and liver in arsenic poisoning group [(5.83 ± 0.29)μg/g Cr, (15.76 ± 1.65)μg/g] and the arsenic contents of urine in curcumin treatment group [(1.07 ± 0.14)μg/g Cr] were obviously higher than those of control group [(0.40 ± 0.14)μg/g Cr, (4.56 ± 1.05)μg/g, all P< 0.05]; compared to arsenic poisoning group, the arsenic contents of urine and liver in curcumin treatment group [(1.07 ± 0.14)μg/g Cr, (5.42 ± 1.76)μg/g] were obviously lower (all P< 0.05). The contents of serum and liver SOD1, CAT and MDA in control group respectively were (102.46 ± 5.03), (29.33 ± 8.13)U/ml, (3.11 ± 0.49)μmol/L and (204.05 ± 18.33), (126.26 ± 13.19)U/mg prot, (1.62 ± 0.42)μmol/g prot. Compared to the control, the activity of serum and liver SOD1 and CAT in arsenic poisoning group [(60.97 ± 7.94), (13.56 ± 5.14)U/ml and (133.66 ± 11.51), (74.01 ± 13.30)U/mg prot] were lower, the contents of MDA [(7.26 ± 0.54) μmol/L and (2.61 ± 0.52)μmol/g prot] were higher (all P< 0.05). Compared to arsenic poisoning group, the activity of serum and liver SOD1 and CAT in curcumin treatment group [(87.39 ± 9.38), (20.45 ± 6.49)U/ml and (178.27 ± 9.32), (93.70 ± 20.35)U/mg prot] were higher, the contents of MDA [(4.34 ± 0.79)μmol/L and (1.92 ± 0.18)μmol/g prot] were lower (all P< 0.05). The protein expressions of SOD1 and CAT in control group respectively were 0.64 ± 0.32 and 0.72 ± 0.31. Compared to the control group, the protein expressions of SOD1 and CAT in pure curcumin group (1.03 ± 0.23, 1.02 ± 0.20) were significantly higher (all P< 0.05) and in arsenic poisoning group (0.34 ± 0.12, 0.39 ± 0.11) were lower (all P< 0.05); Compared with the arsenic poisoning group, the protein expressions of SOD1 and CAT in curcumin treatment group (0.58 ± 0.09, 0.68 ± 0.29) were significantly higher (all P< 0.05). The arsenic content of urine in rats were positively related with arsenic content of liver and the content of MDA [correlation coefficient (r) = 0.952, 0.732, all P< 0.05], but negativity related with the activity of SOD1 and CAT in liver (r = - 0.874, - 0.679, all P< 0.05); the activity of SOD1 and CAT and the content of MDA in serum and liver were positively related (r = 0.796, 0.484, 0.607, all P< 0.05), the activity and protein expression of SOD1 and CAT in liver were positively related (r = 0.748, 0.424, all P< 0.05). Conclusion The curcumin may improve the activity of hepatic antioxidant enzyme in water arsenic-exposed rats and effectively decrease lipid peroxidation damage caused by arsenic via promoting the excretion of arsenic and the protein expression of hepatic antioxidant enzyme. Key words: Arsenites; Curcumin; Liver; Oxidative stress