Table 4 Fitting equations of relationships and correlation coefficients (r) of MDA levels (y) with the levels of GSH (x₁) as well as the activity of SOD (x₂) in the brain, liver, and kidneys of rats administered 0.5g and 1.0g of NiO-NPs (II and III), 0.5g and 1.0g of Co₃O₄-NPs (IV and V) as well as mixtures of NiO-NPs + Co₃O₄-NPs (0.25g + 0.25g, VI) and (0.5g + 0.5g, VII) per kilogram body weight, respectively

MDA levels (nmol/g tissue)

GSH levels (mg/g tissue)

Brain

y = − 2.83x₁ + 40.90

r = − 0.66**

y = − 1.21x₁ + 29.14

r = − 0.89***

y = − 2.03x₁ + 34.23

r = − 0.67**

y = − 0.99x₁ + 29.08

r = − 0.50*

y = − 0.34x₁ + 24.85

r = − 0.86***

y = − 1.27x₁ + 30.90

r = − 0.87***

Liver

y = − 3.37x₁ + 67.23

r = − 0.57*

y = − 6.03x₁ + 84.72

r = − 0.82***

y = − 5.84x₁ + 82.31

r = − 0.70**

y = − 4.77x₁ + 75.24

r = − 0.79***

y = − 4.83x₁ + 73.73

r = − 0.69**

y = − 1.95x₁ + 55.26

r = − 0.93***

Kidney

y = − 9.58x₁ + 110.03

r = − 0.90***

y = − 6.93x₁ + 92.67

r = − 0.76***

y = − 4.96x₁ + 79.58

r = − 0.65**

y = − 3.86x₁ + 71.59

r = − 0.54*

y = − 6.81x₁ + 90.49

r = − 0.82***

y = − 0.89x₁ + 54.26

r = − 0.90***

SOD activity (U/g tissue)

Brain

y = − 0.67x₂ + 5.93

r = − 0.82***

y = − 0.17x₂ + 2.63

r = − 0.50*

y  = − 0.59x₂ + 5.51

r = − 0.76***

y = − 0.18x₂ + 2.90

r = − 0.50*

y = − 0.21x₂ + 3.19

r = − 0.50*

y = − 0.14x₂ + 2.99

r = − 0.82***

Liver

y = − 0.08x₂ + 0.99

r = − 0.68**

y = − 0.09x₂ + 1.07

r = − 0.89***

y = − 0.08x₂ + 0.95

r = − 0.71**

y = − 0.11x₂ + 1.17

r = − 0.74**

y = − 0.07x₂ + 0.89

r = − 0.79***

y = − 0.04x₂ + 0.74

r = − 0.82***

kidney

y = − 0.35x₂ + 4.19

r = − 0.77***

y = − 0.51x₂ + 5.45

r = − 0.76***

y = − 0.59x₂ + 6.21

r = − 0.75***

y = − 0.23x₂ + 3.58

r = − 0.80***

y = − 0.16x₂ + 3.01

r = − 0.58*

y = − 0.12x₂ + 2.99

r = − 0.70**