Hi Charles. If you are interested in a diet-induced model, both SD and Wistars are often used, usually with high fat diets. There are hundreds of papers showing the effects of high fats diets in these models. Both strains show variability in their response, with some rats becoming obese a high-fat diet while others will remain lean. The percentage reportedly is around 50:50. Spontaneous, genetic models exist, as others have mentioned though some argument can be made for diet-induced if you are mimicking human obesity. If my memory is correct there is a poster that looked at the response of both strains to a high fat diet. When I get to work tomorrow I'll see if I'm remembering correctly and will let you know and attach it here.

SD rats do gain weight with age and can become quite obese. Wistar rats similarly gain weight with aging. Here are some links that can answer your question:

http://www.harlan.com/products_and_services/research_models_and_services/research_models/sprague_dawley_outbred_rat.hl

http://tpx.sagepub.com/content/22/1/48.long

http://www.criver.com/files/pdfs/rms/wistar-rats/rm_d_wistar_rat.aspx

http://www.ncbi.nlm.nih.gov/pubmed/2260722

Hope this helps!

The best metabolic syndrome rat model is WNIN/Ob obese rats

Dear Charles. One of the good model of obese rats is Zucker rats.

There are two types of Zucker rat: 1) a lean Zucker rat; 2) and the characteristically obese (or fatty) Zucker rat, which is actually a recessive trait (fa/fa) of the leptin receptor.

Hi Charles. If you are interested in a diet-induced model, both SD and Wistars are often used, usually with high fat diets. There are hundreds of papers showing the effects of high fats diets in these models. Both strains show variability in their response, with some rats becoming obese a high-fat diet while others will remain lean. The percentage reportedly is around 50:50. Spontaneous, genetic models exist, as others have mentioned though some argument can be made for diet-induced if you are mimicking human obesity. If my memory is correct there is a poster that looked at the response of both strains to a high fat diet. When I get to work tomorrow I'll see if I'm remembering correctly and will let you know and attach it here.

There is a model that develops every symptom of metabolic syndrome except atherosclerosis. This is the leptin-deficient SHROB rat. It is similar to the Zucker rat but far more expensive. The advantage is that the SHROB really develops hypertension, while this is doubtful for the Zucker. The problem of feeding high fat diets to conventional strains is that they never develop all the symptoms of metabolic syndrom, especially hypertension.

Hi again Charles, here's the poster I remembered. It compares the Wistar to the SD rat for high fat diet induced insulin resistance and they found that Wistars were more susceptible to obesity and insulin resistance. I'm not sure how many papers have directly compared these two strains, which is really what you need to make the best decision. To speak to some of the other answers, the downside to some genetic, spontaneous models is that most humans are not leptin-deficient (or whatever the gene abnormality may be) and so comparisons to those models need to be made with caution as well. I don't think there's a perfect animal model of the metabolic syndrome out there, it really depends on what your goals are.

Hi, Charles. ob/ob mice and HFD-diet (60%) induced C57BL-6J nice are used to measure obesity and metabolic syndrome related parameters. I found that ob/ob mice are good in overall for metabolic syndrome. But If you are only interested to obesity, I recommend HFD-diet (60%) induced C57BL-6J mice. I hope you can figure it out now.

Dear Charles. Our own experience is that SD rats develop many features of metabolic syndrome when they grow old. I am attaching to you one of our publications comparing young and old SD rats. I hope it helps you¡

Whether SD rats develop obesity with age is highly dependent on the vendor you purchase the animals from. SD rats from Harlan are resistant to age-related and diet-induced obesity.

WE have developed and characterized and published more than a dozen papers on the UC Davis Type 2 Diabetes (UCD_T2DM) Rat which is the rodent model of type 2 diabetes likely to be the most similar to the pathophysiology of the disease in humans (see link below and attached).

http://www.ncbi.nlm.nih.gov/pubmed/?term=UCD-T2DM

Importantly, there is no monogenic leptin/leptin receptor mutation and diabetes occurs in both sexes, although a bit later in female rats.

Absolutely, without any doubt.....ss

The high fat diet used to induce the metabolic syndrome is also a high sugar diet. The delelopment of insulin resistance is mainly the result of de novo lipogenesis (DNL) caused by the fructose, since there is an elevation of palmitoleic acid (16:1n7), a marker of DNL despite that the diet is loaded with fat.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3558438/pdf/1476-511X-12-2.pdf

Another way to induce the metabolic syndrome in rats, mice and men is by using a high-fructose diet. The DNL caused by frustose does the trick. Dr Robert Lustig explains how:

http://www.ncbi.nlm.nih.gov/pubmed/20800122

The answer depends on what you want to study. ¿Do you want to induce SM, and study a specific aspect of the disease once it has been established? Or do you want to study factors that lead some subjects to develop SM versus others who do not develop? etc.

Anyway, the wistar and SD strains develop SM in a a proportion that can be extrapolated to humans (approximately 50:50).

"Wistar and SD Rat can be used as models of HF diet-induced obesity although the metabolic effects caused by HF diet seemed to be more pronounced in Wistar Rat"

citation from Adypocyte 2015  july 15 5 (1) 11-21, Marques C et al

In my experience, SD rats develop MS with age. See the attached pdf.

I want to know too. Thanks, everyone. But I have some question. Which the best age and weight for this model? Please, Shall I help me?