Hypoglycemic Effects of Kefir in Human Intestinal Caco-2 and Streptozotocin-Induced Diabetic ICR Mice
- 주제(키워드) Glucose uptake , Kefir , Hypoglycemic effect
- 발행기관 고려대학교 대학원
- 지도교수 Hong-Yon Cho
- 발행년도 2011
- 학위수여년월 2011. 8
- 학위구분 석사
- 학과 일반대학원 식품생명공학과
- 세부전공 식품생명공학
- 원문페이지 93 p
- 실제URI http://www.dcollection.net/handler/korea/000000026459
- 본문언어 한국어
- 제출원본 000045680000
초록/요약
Kefir is a living relationship and symbiosis of bacteria and yeasts that form grains or cauliflower-like structures. These living organisms ferment milk into the living food kefir. And the kefir is known to have various benefits such as anti-cancer effects, stimulation of the immune system, anti-oxidizing activity, etc. The aim of present study was the evaluation of possible hypoglycemic effect of kefir though in vitro assay using human intestinal epithelial Caco-2 cell line and fluorescent glucose analog , 2-[N-(7-nitrobenz-2-oxa-1, 3-diazol-4-yl) amino]-2-deoxy-D-glucose(2-NBDG). This study was also carried out for investigating the inhibitory effects of 3 kinds of kefir fractions prepared from kefir culture broth on intestinal glucose uptake. Kefir fraction-1 revealed significant high inhibitory effect on intestinal glucose uptake. The mRNA expression of special sodium-dependent glucose transport 1 (SGLT1), hepatocyte nuclear factor-1α (HNF1α) and hepatocyte nuclear factor-1 β (HNF1 β) was down-regulated by treatment of the kefir fractions in reverse transcription polymerase chain reaction (RT-PCR). Furthermore, in vivo study was performed to investigate hypoglycemic effects of kefir, using the streptozotocin-induced diabetic mice. In the study, designed four groups of mice fed with either normal drinking water (control group) or liquid kefir as the sole source of drinking water (experimental group) were reared for 4 weeks, and determined for food efficiency ratio, glucose tolerance level, blood glucose level, histopathological comparison of pancreas section, lipid index, etc. The final blood glucose levels of kefir group were appreciably decreased as compared with those of the diabetic control group. And these kefir groups were slightly relieved functional damage of pancreas β cells by streptozotocin treatment. And also anti-diabetic biomarkers such as lipid indexes were slightly ameliorated by kefir. In order to elucidate these hypoglycemic mechanisms of kefir, mRNA expression levels of SGLT1, HNF-1α, and HNF-1β in small intestine tissue of streptozotocin-induced diabetic mice were determined by RT-PCR. The mRNA expression levels of these blood glucose regulation factors was appreciably decreased in kefir groups as compared with those of the diabetic control group. In present study, I suggest that kefir could play a role in reducing blood glucose level by controlling the dietary glucose absorption due to down-regulation of intestinal glucose uptake related genes such as SGLT1, HNF-1α, and HNF-1β.
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Contents
Abstract i
Contents iii
List of Figures vi
List of Tables ix
List of Abbreviation x
Ⅰ. Introduction 1
Ⅱ. Materials 8
1. Preparation of kefir sample 8
2. Chemicals 8
3. Cell line and medium 8
4. Animals 9
Ⅲ. Methods 10
1. Sample preparation 10
2. In vitro experiments 12
2.1. α-Glucosidase assay 12
2.2. Cell culture 12
2.3. Intestinal glucose uptake assay in Caco-2 cells 14
2.4. RNA isolation 18
2.5. Reverse transcription-polymerase chain reaction analysis 19
3. In vivo experiments 21
3.1. Experimental design 21
3.1.1. Animals 22
3.1.2. Induction of diabetes 24
3.1.3. Experimental diet 25
3.1.4. Intraperitoneal glucose tolerance test 26
3.1.5. Blood sample and serum preparation 27
3.1.6. Sampling procedure of organ for histopathological comparison of pancreas section 28
3.2. Measurements of the biochemical parameters 29
3.2.1. Analysis of lipid content 29
3.3. Small intestine tissue gene expression 30
3.3.1. RNA isolation 30
3.3.2. Reverse transcription-polymerase chain reaction analysis 31
4. Statistical analysis 32
Ⅳ. Results and Discussion 33
1. In vitro studies 33
1.1. Inhibitory effects of kefir fractions on α-glucosidase 33
1.2. Inhibitory effects of kefir fractions on Caco-2 glucose uptake 35
1.3. Does-dependent inhibitory effects of kefir fractions on glucose uptake 37
1.4. Effect of kefir fraction-1 on mRNA expression of glucose uptake factors 41
2. In vivo studies 45
2.1. Body weight gain, food intake, blood glucose and food efficiency ratio 45
2.2. Intraperitoneal glucose tolerance test 45
2.3. Serum biochemical analysis 50
2.3.1. Serum lipid levels 50
2.4. Liver biochemical analysis 52
2.4.1. Liver lipid levels 52
2.5. Pancreas tissue histology and weight 57
2.6. Effect of kefir on mRNA expression of glucose uptake factor in small intestinal tissue 60
V. Conclusion 64
Ⅵ. References 66
Abstract in Korean 74
Acknowledgement in Korean 76
