Development of an Insulin Resistance Diabetes and Colorectal Cancer Mouse Model Induced by Streptozotocin and AOM/DSS

국문 초록 (Abstract)

제2형 당뇨병(Type 2 diabetes mellitus, T2DM)은 인슐린 저항성과 지속적인 만성 저등급 염증을 특징으로 하는 대표적인 대사성 질환으로, 비만, 비알코올성 지방간 질환(NAFLD), 심혈관 질환 등 다양한 합병증과 연관되어 있다. 최근 연구에서 T2DM 환자에서 대장암(colorectal cancer, CRC)의 발생률과 사망률이 유의하게 증가한다는 보고가 제시되면서 두 질환 간의 병태생리적 상호작용에 대한 관심이 높아지고 있다.
본 연구의 목적은 streptozotocin(STZ)를 이용한 당뇨모델과 azoxymethane/ dextran sulfate sodium(AOM/DSS)를 이용하여 당뇨/대장암 복합 마우스모델을 만들어 두 질환 간의 상관관계를 연구하는 것이다.
6주령 수컷 ICR 마우스를 정상대조군(NC), 대장암 유도군(CC), 당뇨 유도군(DM), 당뇨/대장암 복합유도군(DM-CC)의 네 그룹으로 분류하여 실험을 수행하였다. 체중 변화, 혈청 생화학적 지표, 간 조직 무게, 대장 길이를 측정하였으며, H&E와 Oil Red O 조직염색을 통해 간과 대장 조직의 병리학적 변화를 평가하였다. 또한 종양 크기, 지방 축적 정도 및 염증 병변의 발생 수준을 비교·분석하였다.
체중변화는 DM-CC에서는 실험 3주 이후부터, CC는 4주 이후부터 체중 감소를 보였으며, 5주차 체중은 DM, NC, CC, DM-CC 순이었다. 혈청 생화학 분석결과, 혈당(GLU)은 NC 대비 DM에서 2.6배, DM-CC에서 3.4배 증가하였으며 CC는 유사하였다. ALT는 DM와 CC에서는 1.4배, DM-CC에서는 약 2배 증가하였다. ALP는 CC와 DM-CC에서만 1.5배 증가하였다. T-Bil은 DM-CC에서만 2.2배 증가하였다. AST, ALB 및 TP는 군간의 차이가 크지 않았다. 간의 무게는 DM, NC, CC, DM-CC 순이었으며, 대장의 길이는 DM, NC, CC, DM-CC 순이었으나 DM과 CC에서는 차이가 나지 않았다. 즉, 간의 무게는 DM, NC, CC, DM-CC 순이었으며, 대장의 길이는 DM, NC, CC, DM-CC 순이었으나 DM과 CC에서는 차이가 나지 않았고, DM-CC군에서 NC 대비 2.2배로 짧아 졌다. 조직학적 분석 결과, DM과 DM-CC의 간에서 지방축적, 지질축적, 공포화가 관찰되었으며 DM-CC에서 병변이 심하였고, NC와 CC는 정상이었다. 결장의 염증성 병변은 DM에 비해 DM-CC가 심하였으며, 선종은 CC에 비해 DM-CC가 심하였다. 당뇨병은 암의 진행을 가속화하고, 암은 당뇨병의 염증병변을 가속화하는 것이 확인되었다.
본 연구는 STZ 기반 T2DM과 AOM/DSS 기반 CRC를 병합한 ICR mouse 모델이 대사질환과 암이 동반된 병태생리적 특성을 성공적으로 재현함을 입증하였다. 특히 당뇨병 상태가 대장암 진행과 염증 반응을 촉진하는 병리적 증폭효과를 지닌다는 점을 확인하였다. 이러한 결과는 복합 질환 환경에서의 기전 규명 연구뿐 아니라 대사·염증 기반 치료제 개발 및 예방 전략 검증에 활용 가능한 유의한 전임상 실험동물 모델을 제공한다.


주제어 : Streptozotocin, AOM/DSS, Type 2 Diabetes, colorectal cancer, mouse model

다국어 초록 (Multilingual Abstract)

Type 2 diabetes mellitus (T2DM) is a representative metabolic disease characterized by insulin resistance and persistent chronic low-grade inflammation, and is associated with various complications such as obesity, non-alcoholic fatty liver disease (NAFLD), and cardiovascular disease. Recent studies have reported a significant increase in the incidence and mortality of colorectal cancer (CRC) in T2DM patients, raising interest in the pathophysiological interaction between the two diseases.
The purpose of this study was to investigate the correlation between the two diseases by creating a combined diabetes/colorectal cancer mouse model using streptozotocin (STZ) for the diabetes model and azoxymethane/dextran sulfate sodium (AOM/DSS) for the colorectal cancer model.
Six-week-old male ICR mice were divided into four groups for the experiment: Normal Control (NC), Colorectal Cancer induction (CC), Diabetes induction (DM), and Diabetes/Colorectal Cancer combined induction (DM-CC). We measured body weight changes, serum biochemical parameters, liver tissue weight, and colon length, and evaluated pathological changes in liver and colon tissues through H&E and Oil Red O staining. Furthermore, we compared and analyzed the tumor size, degree of fat accumulation, and level of inflammatory lesion incidence.
Body weight loss was observed in the DM-CC group starting from 3 weeks into the experiment, and in the CC group from 4 weeks, with the body weight at 5 weeks being in the order of DM, NC, CC, DM-CC. For serum biochemical analysis, blood glucose (GLU) increased by 2.6 times in the DM group and 3.4 times in the DM-CC group compared to NC; the CC group was similar to NC. ALT increased by 1.4 times in the DM and CC groups, and about 2 times in the DM-CC group. ALP increased by 1.5 times only in the CC and DM-CC groups. T-Bil increased by 2.2 times only in the DM-CC group. AST, ALB, and TP did not show large differences between the groups. Liver weight was in the order of DM, NC, CC, DM-CC, and colon length was in the order of DM, NC, CC, DM-CC, but there was no difference between DM and CC. That is, liver weight was in the order of DM, NC, CC, DM-CC, and colon length was in the order of DM, NC, CC, DM-CC, but there was no difference between DM and CC, and the DM-CC group was 2.2 times shorter than the NC group. Histological analysis showed fat accumulation, lipid deposition, and vacuolization in the livers of the DM and DM-CC groups, with the lesions being more severe in the DM-CC group, while NC and CC were normal. Colonic inflammatory lesions were more severe in DM-CC compared to DM, and adenomas were more severe in DM-CC compared to CC. It was confirmed that diabetes accelerates cancer progression, and cancer accelerates the inflammatory lesions of diabetes.
This study demonstrated that the ICR mouse model combining STZ-based T2DM and AOM/DSS-based CRC successfully reproduces the pathophysiological characteristics of a combined disease with metabolic disorder and cancer. In particular, it was confirmed that the diabetic state possesses a pathological amplification effect that promotes colorectal cancer progression and inflammatory response. These results provide a significant preclinical experimental animal model that can be utilized not only for mechanistic studies in a combined disease environment but also for the development of metabolism- and inflammation-based therapeutics and the verification of prevention strategies.
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Key words : Streptozotocin, AOM/DSS, Type 2 Diabetes, Colorectal Cancer, Mouse Model

목차 (Table of Contents)

• Abstract ⅰ
• List of Tables ⅵ
• List of Figures ⅶ
• Ⅰ. Introduction 1
• Ⅱ. Materials and Methods 4
• 1. Preparation of Reagents
• 2. Experimental Design and Animal Management
• 3. Body Weight Measurement
• 4. Hematological and Serum Biochemical Analysis
• 5. Histological Analysis
• 6. Statistical Analysis
• Ⅲ. Results 10
• Ⅳ. Conclusion 24
• Ⅴ. Discussion 27
• References 30
• Abstract in Korean32