The effect of Q10 and vitamin E, separately or in combination, on memory function, and hippocampal oxidative stress and apoptosis of the male miceexposed to heat stress

Abstract

This study was conducted with the aim of investigating the effect of coenzyme Q10 and vitamin E administration, alone or in combination, on memory impairment, oxidative stress and the expression of apoptotic indicators caused by heat stress in the hippocampus of adult male mice. Materials and methods: 60 Balb/c male mice were randomly divided into five groups of 12 animals, including: control group, heat stress (HS), heat stress + Q10 (HS + Q10), heat stress + vitamin E. (HS+Vit E), and the combination group (HS+ Q10 +Vit E). All groups, except the control group, were subjected to heat stress at 43 ˚C for 15 min/day for 14 consecutive days. In the control and HS groups, oral normal saline was administered daily. In the third to fifth groups, Q10 at a dose of 500 mg/kg, vitamin E at a dose of 250 mg/kg, and a combination of Q10 and vitamin E were gavaged for 14 consecutive days. One day after the last treatment, episodic memory was evaluated in the Lashely III Maze and social memory were assessed in the Social Interaction Test. After the last behavioral test, under deep anesthesia, the right hippocampus region was excised to evaluate oxidative stress indicators [including malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxide (GPx) and total antioxidant capacity (TAC)] and the left hippocampus was extracted to evaluate the expression of proteins involved in apoptosis (including Bax, Bcl-2 and caspase-3, 9) by Western blot method. Results: Our results showed that heat stress significantly impaired learning and memory in both social memory and episodic memory tests. In addition, heat stress led to an increase in lipid peroxidation and a decrease in the levels of TAC and the activity of the antioxidant enzymes, namely SOD and GPx. It also increased the expression of pro-apoptotic proteins and led to a decrease in the expression of Bcl-2 protein. However, the administration of Q10 and vitamin E, alone and together, significantly improved cognitive functions, reduced oxidative stress, improved antioxidant status, and decreased the expression of pro-apoptotic proteins, and increased the expression of anti-apoptotic proteins in the hippocampus of heat stress-subjected animals.