The effects of palm oil tocotrienol-rich fraction supplementation on biochemical parameters, oxidative stress and the vascular wall of streptozotocin-induced diabetic rats - PubMed (original) (raw)

The effects of palm oil tocotrienol-rich fraction supplementation on biochemical parameters, oxidative stress and the vascular wall of streptozotocin-induced diabetic rats

Siti Balkis Budin et al. Clinics (Sao Paulo). 2009.

Abstract

Objective: This study examined the effects of palm oil tocotrienol-rich fractions on streptozotocin-induced diabetic rats.

Methods: Animals were divided into three groups: (i) normal non-diabetic (NDM), (ii) diabetic treated (tocotrienol-rich fractions - TRF) and (iii) diabetic untreated (non-TRF). The treatment group received oral administration of tocotrienol-rich fractions (200 mg/kg body weight) daily for eight weeks. The normal non-diabetic and the diabetic untreated groups were fed standard rat feed. Blood glucose and lipid profiles, oxidative stress markers and morphological changes of the thoracic aorta were evaluated.

Results: Tocotrienol-rich fractions treatment reduced serum glucose and glycated hemoglobin concentrations. The tocotrienol-rich fractions group also showed significantly lower levels of plasma total cholesterol, low-density lipoprotein cholesterol, and triglyceride, as compared to the untreated group. The tocotrienol-rich fractions group had higher levels of high-density lipoprotein cholesterol, as compared to the untreated group. Superoxide dismutase activity and levels of vitamin C in plasma were increased in tocotrienol-rich fractions-treated rats. The levels of plasma and aorta malondealdehyde + 4-hydroxynonenal (MDA + 4-HNE) and oxidative DNA damage were significant following tocotrienol-rich fractions treatment. Electron microscopic examination showed that the normal morphology of the thoracic aorta was disrupted in STZ-diabetic rats. Tocotrienol-rich fractions supplementation resulted in a protective effect on the vessel wall.

Conclusion: These results show that tocotrienol-rich fractions lowers the blood glucose level and improves dyslipidemia. Levels of oxidative stress markers were also reduced by administration of tocotrienol-rich fractions. Vessel wall integrity was maintained due to the positive effects mediated by tocotrienol-rich fractions.

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Figures

Figure 1

Mean weekly water (A) and food (B) intakes in different groups of rats. Food and water intakes were calculated per cage (two animals in a cage), so statistical analysis was not possible

Figure 2

Rat body weight in different groups of study. *p<0.05 vs. NDM group, #p< 0.05 vs. non-TRF group

Figure 3

Electron microscopic findings on the aorta of control rats at eight weeks of study. (A) (Original magnification × 4400) The media layer is composed mainly of smooth muscle cells (SMC) with normal appearance, elastic lamina (EL) and extracellular matrix (EM) between the elastic lamina and smooth muscle cells. (B) (Original magnification × 11000) Extracellular matrix contains scattered collagen fibers (CF) and the endothelial cells appear smooth

Figure 4

Electron microscopic findings on the aorta of the diabetic rats following eight weeks of study. (A) - (Original magnification × 4400) Proliferation and fragmentation of medial smooth muscle cells (SMC) in both the intima and media layers. The extracellular matrix also consists predominantly of amorphous material (AM), as apparent in the media of diabetic rats. Endothelial cells (EC) lost their squamous characteristics and became atrophic. (B) - (Original magnification × 4400) A smooth muscle cell (SMC) is migrating from the media into the intima, breaking through the elastic lamina (EL). (C) - (Original magnification × 6500) A mononuclear cell (MC) and fragmented smooth muscle cell (SMC) at the subendothelial layer of the intima. We observed fragmentation and reduplication of elastic lamina

Figure 5

(Original magnification × 4400) Electron microscopic findings on the aorta of TRF group following eight weeks of study. The elastic lamina (EL) appeared more regular, and smooth muscle cells (SMC) did not actively proliferate. The endothelial cells (EC) still display squamous characteristics

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The effects of palm oil tocotrienol-rich fraction supplementation on biochemical parameters, oxidative stress and the vascular wall of streptozotocin-induced diabetic rats - PubMed (original) (raw)