Neurochemical and Behavior Deficits in Rats with Iron and Rotenone Co-treatment: Role of Redox Imbalance and Neuroprotection by Biochanin A

Abstract

Increasing evidences show that the etiology of Parkinson's disease (PD) is multifactorial. Studying the combined effect of several factors is becoming a hot topic in PD research. On one hand, iron is one of the essential trace metals for human body; on the other hand, iron may be involved in the etiopathogenesis of PD. In our present study, the rats with increased neonatal iron (120 μg/g bodyweight) supplementation were treated with rotenone (0.5 mg/kg) when they were aged to 14 weeks. We observed that iron and rotenone co-treatment induced significant behavior deficits (time-dependent) and striatal dopamine depletion in the male and female rats, while they did not do so when they were used alone. No significant change in striatal 5-hydroxytryptamine content was observed in the male and female rats with iron and rotenone co-treatment. Also, iron and rotenone co-treatment significantly decreased substantia nigra TH expression in the male rats. Furthermore, co-treatment with iron and rotenone significantly induced malondialdehyde increase and glutathione decrease in the substantia nigra of male and female rats. There was no significant change in cerebellar malondialdehyde and glutathione content of the rats co-treated with iron and rotenone. Interestingly, biochanin A significantly attenuated striatal dopamine depletion and improved behavior deficits (dose-dependently) in the male and female rats with iron and rotenone co-treatment. Biochanin A treatment also significantly alleviated substantia nigra TH expression reduction in the male rats co-treated with iron and rotenone. Finally, biochanin A significantly decreased malondialdehyde content and increased glutathione content in the substantia nigra of male and female rats with iron and rotenone co-treatment. Our results indicate that iron and rotenone co-treatment may result in aggravated neurochemical and behavior deficits through inducing redox imbalance and increased neonatal iron supplementation may participate in the etiopathogenesis of PD. Moreover, biochanin A may exert dopaminergic neuroprotection by maintaining redox balance.

Keywords: biochanin A; iron; parkinson's disease; redox balance; roteone.

Figure 1

Effect of iron and rotenone co-treatment on motor behavior of male (A,C,E) and female (B,D,F) rats in rotarod test (A,B: 5 rpm; C,D: 10 rpm; E,F: 15 rpm). Results are expressed as mean ± SEM. N = 9. Latency time was analyzed using multi-factor ANOVA followed by Bonferroni post hoc test. ^#p < 0.05, compared with the rats treated with vehicle, iron or rotenone; ^*p < 0.01, compared with the rats treated with vehicle, iron or rotenone. Veh, vehicle; Ir, iron; Rot, rotenone.

Figure 2

Effect of iron and rotenone co-treatment on motor behavior of male (A,C) and female (B,D) rats in open field test (A,B: crossing number; C,D: rearing number). Results are expressed as mean ± SEM. N = 9. Crossing and rearing number were analyzed using multi-factor ANOVA followed by Bonferroni post hoc test. ^#p < 0.05, compared with the rats treated with vehicle, iron or rotenone; ^*p < 0.01, compared with the rats treated with vehicle, iron or rotenone. Veh, vehicle; Ir, iron; Rot, rotenone.

Figure 3

Effect of iron and rotenone co-treatment on striatal dopamine (A) and 5-hydroxytryptamine (B) conent in male and female rats. Results are expressed as mean ± SEM. N = 9. DA and 5-HT content were analyzed using multi-factor ANOVA followed by Bonferroni post hoc test. ^*p < 0.01, compared with the rats treated with vehicle, iron or rotenone. Veh, vehicle; Ir, iron; Rot, rotenone. DA, dopamine; 5-HT, 5-hydroxytryptamine.

Figure 4

Effect of iron, rotenone and biochanin A co-treatment on substantia nigra TH expression in male rats. Results are expressed as mean ± SEM. N = 9. TH expression was analyzed using multi-factor ANOVA followed by Bonferroni post hoc test. ^*p < 0.01(C), compared with the rats treated with vehicle, iron or rotenone. ^*p < 0.01(D), compared with the rats treated with vehicle. ⁺p < 0.01, compared with the rats co-treated with iron and rotenone. 1, Veh1(saline)+Veh2(sunflower oil); 2, Ir+Veh2; 3, Veh1+Rot; 4, Ir+Rot; 5, Veh1+Veh2+Veh3(DMSO); 6, Ir+Rot+Veh3; 7, Ir+Rot+BA30; 8, Veh1+Veh2+BA30; Veh, vehicle; Ir, iron; Rot, rotenone; BA30, biochanin A (30 mg/kg).

Figure 5

Effect of iron and rotenone co-treatment on malondialdehyde (A,B) and glutathione (C,D) conent in the substantia nigra and cerebellum of male (A,C) and female (B,D) rats. Results are expressed as mean ± SEM. N = 9. MDA and GSH content were analyzed using multi-factor ANOVA followed by Bonferroni post hoc test. ^*p < 0.01, compared with the rats treated with vehicle, iron or rotenone. Veh, vehicle; Ir, iron; Rot, rotenone. MDA, malondialdehyde; GSH, glutathione; SN, substantia nigra; CBM, cerebellum.

Figure 6

Effect of biochanin A on motor behavior (rotarod test) in male and female rats with iron and rotenone co-treatment (A: 5 rpm; B: 10 rpm; C: 15 rpm). Results are expressed as mean ± SEM. N = 9. Latency time was analyzed using multi-factor ANOVA followed by Bonferroni post hoc test. ^*p < 0.01 compared with the vehicle-treated rats. ^▲p < 0.05, compared with the rats co-treated with iron and rotenone. ⁺p < 0.01, compared with the rats co-treated with iron and rotenone. Veh, vehicle; Ir, iron; Rot, rotenone; BA3, biochanin A (3 mg/kg); BA30, biochanin A (30 mg/kg).

Figure 7

Effect of biochanin A on motor behavior (open field test) in male and female rats with iron and rotenone co-treatment (A: crossing number; B: rearing number). Results are expressed as mean ± SEM. N = 9. Crossing and rearing number were analyzed using multi-factor ANOVA followed by Bonferroni post hoc test. ^*p < 0.01 compared with the vehicle-treated rats. ^▲p < 0.05 compared with the rats co-treated with iron and rotenone. Veh, vehicle; Ir, iron; Rot, rotenone; BA3, biochanin A (3 mg/kg); BA30, biochanin A (30 mg/kg).

Figure 8

Effect of biochanin A on striatal dopamine conent in male and female rats with iron and rotenone co-treatment. Results are expressed as mean ± SEM. N = 9. DA content was analyzed using multi-factor ANOVA followed by Bonferroni post hoc test. ^*p < 0.01, compared with the vehicle-treated rats. ^▲p < 0.05, compared with the rats co-treated with iron and rotenone. ⁺p < 0.01, compared with the rats co-treated with iron and rotenone. DA, dopamine; Veh, vehicle; Ir, iron; Rot, rotenone; BA3, biochanin A (3 mg/kg); BA30, biochanin A (30 mg/kg).

Figure 9

Effect of biochanin A on substantia nigra malondialdehyde and glutathione conent in male (A) and female (B) rats with iron and rotenone co-treatment. Results are expressed as mean ± SEM. N = 9. MDA and GSH content were analyzed using multi-factor ANOVA followed by Bonferroni post hoc test. ^*p < 0.01, compared with the vehicle-treated rats. ^▲p < 0.05, compared with the rats co-treated with iron and rotenone. +p < 0.01, compared with the rats co-treated with iron and rotenone. MDA, malondialdehyde; GSH, glutathione; Veh, vehicle; Ir, iron; Rot, rotenone; BA3, biochanin A (3 mg/kg); BA30, biochanin A (30 mg/kg).