Bamboo leaf extract improves spatial learning ability in a rat model with senile dementia

Abstract

Senile dementia (SD) is a syndrome characterized by progressive neurological deterioration. Treatment for the disease is still under investigation. Bamboo leaf extract (B-extract) has been known for its biological efficacy in anti-oxidant and anti-cancer activities. However, study on B-extract for its protection against dementia is very limited. The effect of B-extract on a rat model with SD was examined. B-extract improved spatial learning ability of the dementia rats. The hippocampus of dementia model rats showed reduced levels of acetylcholine (ACh), epinephrine (E), norepinephrine (NE), and dopamine (DA), and increased activities of acetylcholine esterase (AChE) and monoamine oxidase (MAO). Treatment with B-extract 20 mg/(kg·d) for 7 weeks significantly inhibited the enzyme activity compared with untreated dementia rats, and raised the levels of ACh, E, and DA in the hippocampus. In addition, treatment with B-extract elevated the level of γ-aminobutyric acid (GABA), but reduced the level of glutamate (Glu) in the brain. These data suggest that B-extract might be a potential drug in treating impairment of spatial memory in dementia rats by regulating the central neurotransmitter function.

Keywords: Alzheimer’s disease; Bamboo leaf extract; Dementia; Neurotransmitter.

Fig. 1

Timeline of experimental protocol i.p.: intraperitoneal injection; i.c.v.: intracerebroventricular injection

Fig. 2

Escape latency and paths during place navigation after B-extract treatment Average escape latency (a) and path length (b) of the dementia rats were measured with a Morris water maze. Data are expressed as mean±SEM (n=15). ^* P<0.05, ^** P<0.01 vs. control group; ^# P<0.05, ^## P<0.01 vs. SD group. (c) Representative swim paths of the animals. The black circle represents the platform

Fig. 3

Effect of B-extract on the content of ACh, the activities of ChAT and AChE in the hippocampus and cortex of dementia rats Level of the total acetylcholine (ACh) content (a), activity of choline acetytransferase (ChAT) (b), and activity of acetylcholine esterase (AChE) (c) in the hippocampus and cortex of rats (n=8). Data are expressed as mean±SEM. ^* P<0.05, ^*** P<0.001 vs. control group; ^# P<0.05, ^### P<0.001 vs. SD group

Fig. 4

Effect of B-extract on the contents of E, NE, and DA, and the activity of MAO in the hippocampus and cortex of dementia rats The contents of the total epinephrine (E) (a), norepinephrine (NE) (b), and dopamine (DA) (c), and activity of monoamine oxidase (MAO) (d) in the hippocampus and cortex of rats (n=8). Data are expressed as mean±SEM. ^* P<0.05, ^** P<0.01 vs. control group; ^# P<0.05, ^### P<0.001 vs. SD group

Fig. 5

Effect of B-extract on the contents of 5-HT, Glu, and GABA in the hippocampus and cortex of dementia rats The contents of the total 5-hydroxy tryptamine (5-HT) (a), glutamate (Glu) (b), and γ-aminobutyric acid (GABA) (c) in the hippocampus and cortex of rats (n=8). Data are expressed as mean±SEM. ^** P<0.01, ^*** P<0.001 vs. control group; ^# P<0.05 vs. SD group