Table 2.
Interactive and main effects of cadmium (Cd) and zinc (Zn) on the activities of superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR), and catalase (CAT), in the brain tissue of male rats 1,2.
| Parameter | 5 mg Cd/L + 30 mg Zn/L | 5 mg Cd/L + 60 mg Zn/L | ||||||
|---|---|---|---|---|---|---|---|---|
| Main Effect of Cd |
Main Effect of Zn |
Interactive Effect of Cd + Zn |
Cd + Zn Effect vs. Cd Effect + Zn Effect Character of Cd-Zn Interaction |
Main Effect of Cd |
Main Effect of Zn |
Interactive Effect of Cd + Zn |
Cd + Zn Effect vs. Cd Effect + Zn Effect Character of Cd-Zn Interaction |
|
| SOD | 17.47 ‡ | NS | NS | No interaction | NS | 19.68 ‡ | 10.17 † | +24 3 vs. −29 + 0 +24 vs. −29 4 |
| GPx | 8.048 † | NS | NS | No interaction | NS | 8.596 † | 5.412 * | 0 vs. −30 + 0 0 vs. −30 Antagonism |
| GR | 27.33 ‡ | 35.80 ‡ | 16.81 ‡ | 0 vs. +90 + 0 0 vs. +90 Antagonism |
4.274 * | 30.93 ‡ | 43.30 ‡ | −36 vs. +90 + 0 −36 vs. +90 4 |
| CAT | 13.99 ‡ | 7.307 * | 5.000 * | 0 vs. −36 + 0 0 vs. −36 Antagonism |
19.49 ‡ | 9.254 † | NS | No interaction |
1 The outcomes of the ANOVA/MANOVA statistical test are expressed as F values and the level of statistical significance (p). F values having p < 0.05 are recognized statistically significant (where * p < 0.05, † p < 0.01, ‡ p < 0.001). NS—a lack of statistically significant effect (p > 0.05). 2 To describe the possible character of the interaction between Cd and Zn, the effect of co-administration of the two elements was compared to the sum of the effects of their action in the case of separate administration (Cd + Zn 30 effect vs. Cd effect + Zn 30 effect and Cd + Zn 60 effect vs. Cd effect + Zn 60 effect). The effects of Cd, Zn 30, Zn 60, Cd + Zn 30, and Cd + Zn 60 are shown as percentage differences (−, decrease; +, increase) vs. the control. The interaction between Cd and Zn (Cd-Zn 30 or Cd-Zn 60) was considered as antagonistic (antagonism) when the effect of co-administration of Cd and Zn (expressed as a percentage difference vs. the control) was below the sum of the effects noted in the case of their separate administration. 3 The values express percentage differences. 4 The description of the character of the interaction between Cd and Zn was impossible.