Beneficial Effects of Teucrium polium and Metformin on Diabetes-Induced Memory Impairments and Brain Tissue Oxidative Damage in Rats

Abstract

Objective. The effects of hydroalcoholic extract of Teucrium polium and metformin on diabetes-induced memory impairment and brain tissues oxidative damage were investigated. Methods. The rats were divided into: (1) Control, (2) Diabetic, (3) Diabetic-Extract 100 (Dia-Ext 100), (4) Diabetic-Extract 200 (Dia-Ext 200), (5) Diabetic-Extract 400 (Dia-Ext 400), and (6) Diabetic-Metformin (Dia-Met). Groups 3-6 were treated by 100, 200, and 400 mg/kg of the extract or metformin, respectively, for 6 weeks (orally). Results. In passive avoidance test, the latency to enter the dark compartment in Diabetic group was lower than that of Control group (P < 0.01). In Dia-Ext 100, Dia-Ext 200, and Dia-Ext 400 and Metformin groups, the latencies were higher than those of Diabetic group (P < 0.01). Lipid peroxides levels (reported as malondialdehyde, MDA, concentration) in the brain of Diabetic group were higher than Control (P < 0.001). Treatment by all doses of the extract and metformin decreased the MDA concentration (P < 0.01). Conclusions. The results of present study showed that metformin and the hydroalcoholic extract of Teucrium polium prevent diabetes-induced memory deficits in rats. Protection against brain tissues oxidative damage might have a role in the beneficial effects of the extract and metformin.

Figure 1

Comparison of time latency for entering the dark compartment before and at 1 and 24 h after receiving the shock in the experimental groups. Data are presented as mean ± SEM (n = 10 in each group). ^** P < 0.01 in comparison with Control group and ⁺⁺ P < 0.01 and ⁺⁺⁺ P < 0.001 in comparison with Diabetic group.

Figure 2

Comparison of the total time spent in the dark compartment before and at 1 and 24 h after receiving the shock in the experimental groups. Data are presented as mean ± SEM (n = 10 in each group). ^* P < 0.05 in comparison with Control group and ⁺ P < 0.05 and ⁺⁺ P < 0.01 in comparison with Diabetic group.

Figure 3

Comparison of the total time spent in the light compartment before and at 1 and 24 h after receiving the shock in the experimental groups. Data are presented as mean ± SEM (n = 10 in each group). ^* P < 0.05 in comparison with Control group and ⁺ P < 0.05 in comparison with Diabetic group.

Figure 4

The MDA concentrations (a) and total thiol concentrations (b) in hippocampal tissues of 6 groups. Data are shown as mean ± SEM of 10 animals per group. ^* P < 0.05 and ^*** P < 0.001 in comparison with Control group and ⁺⁺ P < 0.01 and ⁺⁺⁺ P < 0.001 in comparison with Diabetic group.

Figure 5

The MDA concentrations (a) and total thiol concentrations (b) in cortical tissues of 6 groups. Data are shown as mean ± SEM of 10 animals per group. ^*** P < 0.001 in comparison with Control group and ⁺⁺ P < 0.01 and ⁺⁺⁺ P < 0.001 in comparison with Diabetic group.

Figure 6

The blood glucose concentrations of 6 groups. Data are shown as mean ± SEM of 10 animals per group. ^** P < 0.01 in comparison with Control group.