The recent news that Kate Middleton, the Duchess of Cambridge, might be suffering from Crohn's Disease (CD) has drawn widespread public attention, leading more people to become aware of this condition, often referred to as "green cancer."[1] In reality, Crohn's Disease is not a true cancer but a type of chronic inflammatory bowel disease (IBD). It is called "green cancer" due to its diverse clinical manifestations, significant individual variations, wide range of affected areas, high recurrence rate, and treatment challenges. Once diagnosed, patients will need to manage the disease for the rest of their lives.

Current Status of Inflammatory Bowel Disease (IBD)

Inflammatory Bowel Disease (IBD) is an idiopathic inflammatory disorder of the intestines, primarily affecting the ileum, rectum, and colon. Its clinical manifestations include diarrhea, abdominal pain, and possibly bloody stools. IBD consists of two subtypes: Ulcerative Colitis (UC) and Crohn's Disease (CD). The pathogenesis of IBD is highly complex, involving genetics, immune response, environmental factors, and intestinal infections. Currently, more than 10 million people worldwide suffer from IBD, with the incidence rate in China exceeding 3 per 100,000 people.[2] However, the diagnosis of IBD is complicated, and there is no cure available at present. As the cost of disease management continues to rise, there is an urgent need for effective strategies to alleviate the burden of this condition.

Figure 1. Classification of Inflammatory Bowel Disease (IBD) [3]

The Relationship Between IL10 and IBD

Interleukin-10 (IL10) is a key susceptibility gene for Inflammatory Bowel Disease (IBD), with its functional deficiencies being a central mechanism in the pathogenesis of Ulcerative Colitis (UC).[4] Additionally, genetic polymorphisms of IL10 can lead to the development of UC or Crohn's Disease (CD).[5] In patients with very early-onset IBD (VEO-IBD) who have a significant family history, there is a high detection rate of monogenic mutations in IL10 and its receptor IL10R.[6] Therefore, IL10 knockout (KO) mice, which can mimic human IBD clinical phenotypes, are the most commonly used genetic model in research.[7] In IL10 KO mice, spontaneous and chronic colitis occurs under the influence of IL-23 and Th1-like inflammation, as well as microbial stimulation. This phenotype is highly dependent on the genetic background. Under SPF conditions, BALB/c background IL10 KO mice exhibit early onset, high disease penetrance, severe disease phenotype, and minimal phenotypic variation among individuals, accurately replicating various aspects of human chronic colitis within a reasonable timeframe.[8-9] Thus, they offer significant advantages in disease mechanism research and screening potential drugs.

Figure 2. Widely Used Mouse Models of IBD [7]

BALB/c-Il10 Knockout Mice for IBD Research

Cyagen has developed various mouse models for research on inflammatory diseases and the screening and evaluation of therapeutic drugs. Among these models, the BALB/c-Il10 KO mouse (Product Code: C001527) is an Il10 gene knockout model on a BALB/c background. It exhibits spontaneous inflammatory bowel disease, characterized by abnormal weight, reduced survival rate, elevated levels of inflammatory cytokines, intestinal inflammation, and abnormal intestinal phenotypes. The specific data are as follows.

Growth Curve and Survival Curve

The body weight of BALB/c-Il10 KO mice is reduced compared to wild-type (WT) mice. Starting from the 10th week, mice begin to die, and their survival rate further decreases as the disease progresses.

Figure 3. Growth and Survival Curves of BALB/c-Il10 KO Mice

Disease Incidence and Disease Activity Index (DAI)

The disease incidence in BALB/c-Il10 KO mice was quantitatively analyzed based on the Disease Activity Index (DAI) and Crohn's Disease Activity Index (CDAI). The results indicate that BALB/c-Il10 KO mice begin to exhibit symptoms at 8 to 9 weeks of age. Male mice have an earlier onset of disease compared to female mice, with all male mice developing the disease by around 16 weeks of age. The severity of the disease progressively increases as the mice age.

Figure 4. Disease Incidence and Disease Scores of BALB/c-Il10 KO Mice

Physical Appearance and Body Morphology

Observing the physical appearance and body morphology of male BALB/c-Il10 KO mice reveals that by around 22 weeks of age, their colitis phenotype is very severe. The mice exhibit symptoms such as diarrhea, bloody stools, rectal prolapse, and abnormal body shape.

Figure 5. Appearance of Male BALB/c-Il10 KO Mice at 22 Weeks of Age

Colorectal Anatomical Examination

Dissection of wild-type mice and diseased BALB/c-Il10 KO mice revealed that BALB/c-Il10 KO mice have thickened colorectal walls, enlarged intestines, and a reddened color, indicating inflammation. Additionally, the intestinal contents are viscous and diffuse, with irregularly shaped feces. Data also show that male mice develop the disease earlier and more severely than female mice.

Figure 6. Colorectal Anatomical Comparison Between Wild-Type Mice and Diseased BALB/c-Il10 KO Mice

Intestinal Tissue H&E Staining

Colorectal tissues from wild-type mice and BALB/c-Il10 KO mice were subjected to H&E staining. The results showed that in the early stage of the disease (10 weeks), BALB/c-Il10 KO mice exhibited phenotypes such as inflammatory cell aggregation and crypt damage in the colorectal tissues. As the disease progressed to the late stage (22 weeks), these phenotypes became more severe, with additional signs such as goblet cell loss also observed.

Figure 7. Comparison of Intestinal Tissue H&E Staining Results Between Wild-Type (WT) Mice and BALB/c-Il10 KO Mice

Expression Levels of Inflammatory Cytokines

RT-qPCR results of inflammatory cytokine expression in mouse intestinal tissues showed that, compared to wild-type and non-diseased BALB/c-Il10 KO mice, the expression levels of pro-inflammatory cytokines such as TNF-α and IL6 were significantly elevated in the intestinal tissues of diseased BALB/c-Il10 KO mice.

Figure 8. Significantly Elevated Levels of Inflammatory Cytokines in Diseased BALB/c-Il10 KO Mice

Conclusion

The BALB/c-Il10 KO mouse (Product Code: C001527) begins to show symptoms at 8 to 9 weeks of age, primarily manifesting as weight loss, reduced survival rate, elevated levels of inflammatory cytokines, intestinal inflammation, and abnormal intestinal phenotypes. Male mice develop the disease earlier and more severely, with severe symptoms such as diarrhea, bloody stools, and rectal prolapse appearing by 22 weeks of age. Additionally, the mice exhibit pronounced intestinal inflammation phenotypes, including thickened colorectal walls, enlarged intestines, reddened color, viscous and diffuse intestinal contents, and irregularly shaped feces. Histological examination reveals that in the early stages of the disease, the colorectal tissues of BALB/c-Il10 KO mice show significant inflammatory cell aggregation and crypt damage, progressing to goblet cell loss in the later stages. The expression levels of inflammatory cytokines such as TNF-α and IL6 are significantly elevated in diseased BALB/c-Il10 KO mice. Therefore, the BALB/c-Il10 KO mouse, as a spontaneous inflammatory bowel disease model, can be used for the study of Crohn's Disease (CD) and colitis, as well as in research areas related to cancer, innate and adaptive immunity, and other inflammatory or autoimmune conditions.

In addition, Cyagen also offers a variety of spontaneous or induced inflammation disease models and humanized target gene disease models to meet the experimental needs of researchers in the fields of inflammation and autoimmune studies. Contact us for a free consultation.

 

References:

[1]Royal Family News. "Kate Middleton Surgery Colon Crohn's Disease." Last modified March 10, 2024. https://royalfamily.news/kate-middleton-surgery-colon-crohns-disease/.
[2]Zhang Y, Liu J, Han X, Jiang H, Zhang L, Hu J, Shi L, Li J. Long-term trends in the burden of inflammatory bowel disease in China over three decades: A joinpoint regression and age-period-cohort analysis based on GBD 2019. Front Public Health. 2022 Sep 7;10:994619.
[3]Johns Hopkins Medicine. "Inflammatory Bowel Disease." Last modified March 10, 2024. https://www.hopkinsmedicine.org/health/conditions-and-diseases/inflammatory-bowel-disease.
[4]Franke A, Balschun T, Karlsen TH, Sventoraityte J, Nikolaus S, Mayr G, Domingues FS, Albrecht M, Nothnagel M, Ellinghaus D, Sina C, Onnie CM, Weersma RK, Stokkers PC, Wijmenga C, Gazouli M, Strachan D, McArdle WL, Vermeire S, Rutgeerts P, Rosenstiel P, Krawczak M, Vatn MH; IBSEN study group; Mathew CG, Schreiber S. Sequence variants in IL10, ARPC2 and multiple other loci contribute to ulcerative colitis susceptibility. Nat Genet. 2008 Nov;40(11):1319-23.
[5]Zhu L, Shi T, Zhong C, Wang Y, Chang M, Liu X. IL-10 and IL-10 Receptor Mutations in Very Early Onset Inflammatory Bowel Disease. Gastroenterology Res. 2017 Apr;10(2):65-69. 
[6]Kotlarz D, Beier R, Murugan D, Diestelhorst J, Jensen O, Boztug K, Pfeifer D, Kreipe H, Pfister ED, Baumann U, Puchalka J, Bohne J, Egritas O, Dalgic B, Kolho KL, Sauerbrey A, Buderus S, Güngör T, Enninger A, Koda YK, Guariso G, Weiss B, Corbacioglu S, Socha P, Uslu N, Metin A, Wahbeh GT, Husain K, Ramadan D, Al-Herz W, Grimbacher B, Sauer M, Sykora KW, Koletzko S, Klein C. Loss of interleukin-10 signaling and infantile inflammatory bowel disease: implications for diagnosis and therapy. Gastroenterology. 2012 Aug;143(2):347-55.
[7]Kiesler P, Fuss IJ, Strober W. Experimental Models of Inflammatory Bowel Diseases. Cell Mol Gastroenterol Hepatol. 2015 Mar 1;1(2):154-170.
[8]Berg DJ, Davidson N, Kühn R, Müller W, Menon S, Holland G, Thompson-Snipes L, Leach MW, Rennick D. Enterocolitis and colon cancer in interleukin-10-deficient mice are associated with aberrant cytokine production and CD4(+) TH1-like responses. J Clin Invest. 1996 Aug 15;98(4):1010-20.
[9]Sellon RK, Tonkonogy S, Schultz M, Dieleman LA, Grenther W, Balish E, Rennick DM, Sartor RB. Resident enteric bacteria are necessary for development of spontaneous colitis and immune system activation in interleukin-10-deficient mice. Infect Immun. 1998 Nov;66(11):5224-31.

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