Effects and Mechanisms of Chitosan and ChitosanOligosaccharide on Hepatic Lipogenesis and Lipid Peroxidation, Adipose Lipolysis, and Intestinal Lipid Absorption in Rats with High-Fat Diet-Induced Obesity

Abstract

Chitosan and its derivative, chitosan oligosaccharide (CO), possess hypolipidemic and anti-obesity effects. However, it is still unclear if the mechanisms are different or similar between chitosan and CO. This study was designed to investigate and compare the effects of CO and high-molecular-weight chitosan (HC) on liver lipogenesis and lipid peroxidation, adipose lipolysis, and intestinal lipid absorption in high-fat (HF) diet-fed rats for 12 weeks. Rats were divided into four groups: normal control diet (NC), HF diet, HF diet+5% HC, and HF diet+5% CO. Both HC and CO supplementation could reduce liver lipid biosynthesis, but HC had a better effect than CO on improving liver lipid accumulation in HF diet-fed rats. The increased levels of triglyceride decreased lipolysis rate, and increased lipoprotein lipase activity in the perirenal adipose tissue of HF diet-fed rats could be significantly reversed by both HC and CO supplementation. HC, but not CO, supplementation promoted liver antioxidant enzymes glutathione peroxidase and superoxide dismutase activities and reduced liver lipid peroxidation. In the intestines, CO, but not HC, supplementation reduced lipid absorption by reducing the expression of fabp2 and fatp4 mRNA. These results suggest that HC and CO have different mechanisms for improving lipid metabolism in HF diet-fed rats.

Chitosan Oligosaccharide Alleviates Abnormal Glucose Metabolism without Inhibition of Hepatic Lipid Accumulation in a High-Fat Diet/Streptozotocin-Induced Diabetic Rat Model

“…COS has recently been found to possess the beneficial effects on HF diet-induced non-alcoholic fatty liver disease in mice [ 22 ]. Recently, our previous study also found that COS supplementation could effectively reduce the levels of TC and TG in the plasma and liver of HF diet-induced obese rats [ 23 ]. Unexpectedly, the present study found that COS supplementation could not significantly reduce the increased levels of TC and TG in the liver of HF diet/STZ-induced diabetic rats.…”

“…Nevertheless, supplementation with COS in the DF diabetic rats could not significantly decrease the hepatic lipid accumulation. The previous findings suggested that 5% COS may have potential for toxicological side effect in a HF diet-fed condition [ 23 ]. Based on the above reasoning, the findings of present study suggest that 1% COS may be more suitable as a dose for improving diabetes.…”

“…Rats were divided into six groups: normal control (NC group), HF diet (HF group), STZ-induced diabetes with HF diet (DF group), DF with 0.5% COS (D0.5F group), DF with 1% COS (D1F group), and DF with 5% COS (D5F group). The dosages for COS were selected according to the previous reports [ 23 , 28 ] and our preliminary tests. These diet compositions were shown in Table 4 .…”

Influence of Dietary Chitosan Feeding Duration on Glucose and Lipid Metabolism in a Diabetic Rat Model

“…We also found that high MW chitosan had a higher potential than low MW chitosan in reducing hypercholesterolemia and intestinal disaccharidase activity in STZ-induced diabetic rats [ 9 ]. We further found that both 5% chitosan oligosaccharide (COS) and 5% high MW chitosan (CS) were capable of improving lipid metabolism in an HF diet-fed rat model through different mechanisms [ 15 ]. Our previous study has also shown that CS (high MW) can reduce the plasma fructosamine, leptin, total cholesterol, and HOMA-IR more effectively than low MW chitosan in diabetic rats [ 13 ].…”

“…Lipolysis rate was determined by the measurement of glycerol levels as described previously [ 15 ]. A glycerol detection kit (Randox, Antrim, UK) was used to assay the levels of glycerol in samples.…”