Beneficial effects of geminated brown rice on cardiovascular risk factors in LDL receptor knockout mice

Atherosclerotic cardiovascular disease (CVD) is one of the major
causes of morbidity and mortality. Accumulating evidence suggests
that an appropriate intake of whole grains is associated with reduced
CVD risk factors. The exact mechanisms, however, are still not clearly
understood. Chinese geminated brown rice (GBR) is believed to have
beneficial metabolic benefits according to Chinese folk medicine, and
lowered cholesterol in hyperlipidemic patients. We hypothesized that
adequately regular intakes of GBR will reduce CVD risk factors
through beneficial alterations in endogenous antioxidant status, lipid
profile and inflammatory pathways in low-density lipoprotein receptor
knockout (LDL-r-KO) mice. To test this hypothesis, three groups of
male LDL-r-KO mice were fed with one of the following diets for
24 weeks: (a) Mouse Diet 9F-LabDiet (the chow) was used as the control
diet; Mouse Diet 9F-LabDiet was replaced with 60% (w/w) (experimental
diets) of (b) Chinese white rice (CWR) or (c) GBR from China. All
diets were supplemented with 0.06% (w/w) dietary cholesterol to accelerate
atherogenesis. LDL-r-KO mice are well known models for
studying LDL oxidation and atherosclerosis. The Animal Care Committee
at the University of Manitoba approved this study. Blood samples,
hearts, liver, and feces were collected and used for biochemical and
histological examination. Consumption of GBR significantly reduced
(P=0.003) atherosclerotic lesion development in aortic roots as compared
to CWR, but there was no significant difference (P=0.4) as compared
to the control group. However, there were no significant
differences among lipid profile (plasma total cholesterol, LDL, highdensity
lipoprotein, very low-density lipoprotein, and triglyceride),
and antioxidant enzymes among all the groups. On the other hand,
monocyte adhesion to aorta from GBR treated LDL-r-KO mice were significantly lower than that from CWR mice. Current data suggest
that GBR may be beneficial for prevention of atherosclerotic lesion
development in LDL-r-KO mice; this may be, at least in part, due to the
inhibition of vascular inflammation. Additional studies are necessary
to understand mechanisms of action. (Supported by Yuanwang Fuqi
Agricultural Product Co. Nanjing, China, Saudi Cultural Bureau, and
NSERC.)