Investigating the effect of telmisartan on acrylamide-induced neurotoxicity through in vitro and in vivo methods

Abstract

Objectives: Acrylamide (ACR) is an environmental contaminant and neurotoxin. Telmisartan is an AT1 blocker that has neuroprotective properties basically through its anti-oxidant effect. The effect of telmisartan on ACR-induced neurotoxicity was investigated in this study.

Materials and methods: Male Wistar rats were randomly assigned to eight groups (n=6): 1:Control (normal saline), 2:ACR (50 mg/kg, 11 days, IP), 3:ACR+vitamin E (200 mg/kg, every other day, 11 days), 4-6:ACR+telmisartan (0.6, 1.25, and 2.5 mg/kg, 11 days, IP), 7:ACR+telmisartan (0.6 mg/kg, days 3-11), 8:Telmisartan (2.5 mg/kg, 11 days). The behavioral test and blood pressure were assessed after 11 days. Then, the levels of MDA and GSH in brain tissue were measured. The MTT assay was used to evaluate the effect of telmisartan on ACR-induced cytotoxicity.

Results: Exposing PC12 cells to ACR decreased cell viability versus the control group. Pretreating PC12 cells with telmisartan (0.0125, 0.025 µM) enhanced cell viability compared with the ACR group. Compared with control samples, ACR significantly caused motor impairment, elevated MDA, and reduced GSH levels. Locomotor abnormalities were significantly ameliorated by telmisartan (0.6, 1.25 mg/kg, 11 days) and vitamin E versus the ACR group. Receiving telmisartan (0.6, 1.25, and 2.5 mg/kg) and vitamin E along with ACR decreased MDA levels and enhanced GSH content compared with the ACR group. There was no significant difference in animal blood pressure between the groups.

Conclusion: Oxidative stress has a chief role in the neurotoxicity of ACR. Telmisartan (in doses that do not affect blood pressure) ameliorated ACR-induced toxicity by inhibiting oxidative stress.

Keywords: Anti-oxidants; Cell survival; Motor disorders; Neurotoxins; PC12 cells; Vitamin E.

Figure 1

A: Effect of 1–20 mM ACR concentrations and B: 0–1.6 µM telmisartan on PC12 cells for 24 hr. The data are presented as mean±SD (n=4). ANOVA and post-test Tukey–Kramer were used for statistical analysis. ### P<0.001 and # P<0.05 compared with the control group

Figure 2

Effect of telmisartan (0.0125–0.8 µM) on the viability of PC12 cells exposed to ACR for 24 hr. The data are presented as mean±SD (n=4). ANOVA and post-test Tukey–Kramer were used for statistical analysis. ### P<0.001 compared with the control group, *** P<0.001 compared with the ACR group

Figure 3

Effect of ACR (50 mg/kg), telmisartan (0.6, 1.25, and 2.5 mg/kg), and vitamin E (200 mg/kg) on the behavioral index (gait scores) in rats. The data are presented in mean±SD (n=6). The Nonparametric Kruskal-Wallis test was used for statistical analysis. ### P<0.001 compared with the control group, ** P<0.01 and * P<0.05 compared with the ACR group ACR: acrylamide; Tel: telmisartan

Figure 4

Effect of ACR (50 mg/kg), telmisartan (0.6, 1.25, and 2.5 mg/kg), and vitamin E (200 mg/kg) on A: MDA level and B: GSH level of the cerebral cortex of the brain. The data are presented as mean±SD (n=6). ANOVA and post-test Tukey–Kramer were used for statistical analysis. ### P<0.001 and ## P<0.01 compared with the control group, *** P<0.001 and ** P<0.01 compared with the ACR group

Figure 5

Effect of ACR (50 mg/kg), telmisartan (0.6, 1.25, and 2.5 mg/kg), and vitamin E (200 mg/kg) on systolic blood pressure. The data are presented as mean±SD (n=6). ANOVA and post-test Tukey–Kramer were used for statistical analysis