Memory Recovery Effect of a New Bioactive Innovative Combination in Rats with Experimental Dementia

Abstract

Alzheimer's disease manifests as a complex pathological condition, with neuroinflammation, oxidative stress and cholinergic dysfunction being a few of the many pathological changes. Due to the complexity of the disease, current therapeutic strategies aim at a multitargeted approach, often relying on a combination of substances with versatile and complementary effects. In the present study, a unique combination of α-lipoic acid, citicoline, extracts of leaves from olive tree and green tea, vitamin D3, selenium and an immune-supporting complex was tested in scopolamine-induced dementia in rats. Using behavioral and biochemical methods, we assessed the effects of the combination on learning and memory, and elucidated the mechanisms of these effects. Our results showed that, compared to its components, the experimental combination was most efficient in improving short- and long-term memory as assessed by the step-through method as well as spatial memory as assessed by T-maze and Barnes maze underlined by decreases in AChE activity (p < 0.05) and LPO (p < 0.001), increases in SOD activity in the cortex (p < 0.05) and increases in catalase (p < 0.05) and GPx (p < 0.01) activities and BDNF (p < 0.001) and pCREB (p < 0.05) levels in the hippocampus. No significant histopathological changes or blood parameter changes were detected, making the experimental combination an effective and safe candidate in a multitargeted treatment of AD.

Keywords: Alzheimer’s disease; citicoline; extract of leaves green tea; extract of leaves olive tree; scopolamine; selenium; vitamin D3; α-lipoic acid.

Scheme 1

Schematic timeline of the experimental paradigm.

Figure 1

Effects of the experimental combination and its components, citicoline, alpha-lipoic acid (LA) and alpha-lipoic acid and citicoline (LA+citicoline) on learning and memory in a scopolamine model of dementia in rats. Step-through latency is assessed at 1 h, 24 h, and on the 12th day ((A–C), respectively) and T-maze performance is evaluated on the 12th day after the beginning of scopolamine treatment (D) for the control, Sco, Sco+E, Sco+citicoline; Sco+LA; Sco+LA+citicoline. Barnes maze total latency is assessed when Barnes maze training was performed before scopolamine treatment (E) and under scopolamine treatment (F). RI in the NOR study is evaluated on the 12th day after the beginning of scopolamine treatment (G). Data are expressed as the mean ± SEM; significant differences among experimental groups are denoted with “*” whenever groups are compared with the saline (control) group and denoted with “#” whenever groups are compared with the dementia (Sco) group. The number of “*” or “#” above bars is assigned as follows: # or * at p < 0.05; ## or ** at p < 0.01, ### p < 0.001.

Figure 2

Effects of the experimental combination and its components, citicoline, alpha-lipoic acid (LA) and alpha-lipoic acid and citicoline (LA+citicoline) on AChE in the cortex (A) and hippocampus (B) of scopolamine-treated rats. Data are expressed as the mean ± SEM; significant differences among experimental groups are denoted with “*” whenever groups are compared with the saline (control) group and denoted with “#” whenever groups are compared with the dementia (Sco) group. The number of “*” or “#” above bars is assigned as follows: # at p < 0.05; ## at p < 0.01; ### or *** at p < 0.001.

Figure 3

Effects of the experimental combination and its components, citicoline, alpha-lipoic acid (LA) and alpha-lipoic acid and citicoline (LA+citicoline) on the MDA levels (as a measure of lipid peroxidation, LPO) and tGSH in the cortex (A,C) and hippocampus (B,D) of scopolamine-treated rats. Data are expressed as mean ± SEM; significant differences among experimental groups are denoted with “*” whenever groups are compared with the saline (control) group and denoted with “#” whenever groups are compared with the dementia (Sco) group. The number of “*” or “#” above bars is assigned as follows: # or * at p < 0.05; ## or ** at p < 0.01; ### or *** at p < 0.001.

Figure 3

Effects of the experimental combination and its components, citicoline, alpha-lipoic acid (LA) and alpha-lipoic acid and citicoline (LA+citicoline) on the MDA levels (as a measure of lipid peroxidation, LPO) and tGSH in the cortex (A,C) and hippocampus (B,D) of scopolamine-treated rats. Data are expressed as mean ± SEM; significant differences among experimental groups are denoted with “*” whenever groups are compared with the saline (control) group and denoted with “#” whenever groups are compared with the dementia (Sco) group. The number of “*” or “#” above bars is assigned as follows: # or * at p < 0.05; ## or ** at p < 0.01; ### or *** at p < 0.001.

Figure 4

Effects of the experimental combination and its components, citicoline, alpha-lipoic acid (LA) and alpha-lipoic acid and citicoline (LA+citicoline) on SOD, catalase and GPx activity in the cortex (A,C,E) and on SOD, catalase and GPx activity in the hippocampus (B,D,F) of scopolamine-treated rats. Data are expressed as mean ± SEM; significant differences among experimental groups are denoted with “*” whenever groups are compared with the saline (control) group and denoted with “#” whenever groups are compared with the dementia (Sco) group. The number of “∗” or “#” above bars is assigned as follows: # or * at p < 0.05; ** at p < 0.01; ### or *** at p < 0.001.

Figure 4

Effects of the experimental combination and its components, citicoline, alpha-lipoic acid (LA) and alpha-lipoic acid and citicoline (LA+citicoline) on SOD, catalase and GPx activity in the cortex (A,C,E) and on SOD, catalase and GPx activity in the hippocampus (B,D,F) of scopolamine-treated rats. Data are expressed as mean ± SEM; significant differences among experimental groups are denoted with “*” whenever groups are compared with the saline (control) group and denoted with “#” whenever groups are compared with the dementia (Sco) group. The number of “∗” or “#” above bars is assigned as follows: # or * at p < 0.05; ** at p < 0.01; ### or *** at p < 0.001.

Figure 5

Effects of the experimental combination and its components, citicoline, alpha-lipoic acid (LA) and alpha-lipoic acid and citicoline (LA+citicoline) on BDNF levels in the cortex and hippocampus (A,B) and on pCREB levels in the cortex and hippocampus (C,D) of scopolamine-treated rats. Data are expressed as mean ± SEM; significant differences among experimental groups are denoted with “*” whenever groups are compared with the saline (control) group and denoted with “#” whenever groups are compared with the dementia (Sco) group. The number of “*” or “#” above bars is assigned as follows: # or * at p < 0.05; ## or ** at p < 0.01; ### or *** at p < 0.001.

Figure 6

Effects of the experimental combination and its components, citicoline, alpha-lipoic acid (LA) and alpha-lipoic acid and citicoline (LA+citicoline) on CRP levels of scopolamine-treated rats. Data are expressed as mean ± SEM; significant differences among experimental groups are denoted with “*” whenever groups are compared with the saline (control) group and denoted with “#” whenever groups are compared with the dementia (Sco) group. The number of “*” or “#” above bars is assigned as follows: # at p < 0.05; ** at p < 0.01; ### or *** at p < 0.001.

Figure 7

Radar plots showing the overall treatment profiles, represented as the percent change from baseline for each experimental parameter. A profile of healthy controls, depicted in gray, is superimposed on each treatment profile, depicted in black, to illustrate the extent of recovery or impairment (in the case of scopolamine treatment) for each parameter. (A) Profile of control treatment; (B) profile of scopolamine treatment; (C) profile of the treatment with scopolamine and the experimental combination (Sco+E); (D) profile of the treatment with scopolamine and citicoline (Sco+citicoline); (E) profile of the treatment with scopolamine and lipoic acid (Sco+ALA); (F) profile of the treatment with scopolamine and the combination of lipoic acid and citicoline (Sco+ALA+citicoline).