Soy isoflavones improve spatial delayed matching-to-place performance and reduce cholinergic neuron loss in elderly male rats.
To investigate the protective activity of soy isoflavones on neurons, the effects of isoflavones on cholinergic enzyme activity, immunoreactivities of cholinergic enzyme, and delayed matching-to-place (DMP) performance were measured in normal elderly rats. Male Sprague-Dawley rats (n = 48; 10 mo old) were assigned to 3 groups: CD (control diet), ISO 0.3 (0.3 g/kg soy isoflavones diet), and ISO 1.2 (1.2 g/kg soy isoflavones diet). After 16 wk of consuming these diets, choline acetyltransferase (ChAT) activity in the ISO 0.3 group was greater in cortex and basal forebrain (BF; P < 0.05) than in controls. In BF, ChAT activity was also significantly greater in the ISO 1.2 group than in control rats. Acetylcholine esterase (AChE) activity in the ISO 0.3 group was significantly inhibited in cortex, BF, and hippocampus and in the ISO 1.2 group in cortex and hippocampus. Choline acetyltransferase immunoreactivity (ChAT-IR) in the ISO 1.2 group was significantly greater than in controls in the medial septum area. ChAT-IR in the ISO 0.3 and ISO 1.2 groups was significantly higher than in the CD group in the hippocampus CA1 area. Spatial DMP performance by the ISO 0.3 group showed significantly shorter swimming time than by the CD group. These findings show that soy isoflavones can influence the brain cholinergic system and reduce age-related neuron loss and cognition decline in male rats.
Lee
Yoon-Bok
YB
Central Research Institute, Dr. Chung's Food Company Limited, Choongchungbuk-Do, 361-782, Korea.
Lee
Hyong Joo
HJ
Won
Moo Ho
MH
Hwang
In Koo
IK
Kang
Tae-Cheon
TC
Lee
Jae-Yong
JY
Nam
Sang-Yoon
SY
Kim
Kang-Sung
KS
Kim
Eugene
E
Cheon
Sang-Hee
SH
Sohn
Heon-Soo
HS
D000375:Aging; D000818:Animals; D001921:Brain / Q000187:drug effects / Q000201:enzymology / Q000473:pathology; D002795:Choline O-Acetyltransferase / Q000378:metabolism; D004032:Diet; D007529:Isoflavones / Q000008:administration & dosage / Q000627:therapeutic use*; D008297:Male; D008568:Memory / Q000187:drug effects*; D009043:Motor Activity / Q000187:drug effects*; D051381:Rats; D017207:Rats, Sprague-Dawley; D030262:Soybean Proteins / Q000008:administration & dosage / Q000627:therapeutic use*
D007529:Isoflavones; D030262:Soybean Proteins; D002795:Choline O-Acetyltransferase