It has been shown that gut microbiota on diet-induced obesity promotes obesity-associated inflammation and insulin resistance. In addition, probiotics improve glycemic control and insulin sensitivity in several animal models. Our previous studies demonstrated that chronic high-fat diet (HFD) consumption can not only induce obese-insulin resistance, but also reduce jaw bone density. However, the effect of probiotics on the insulin sensitivity and jaw bone density in obese-insulin resistant rats has not been investigated. The present study hypothesized that probiotics, Lactobacillus paracasei ST11 HP4, improve the peripheral insulin sensitivity and jaw bone density in obese-insulin resistant rats. Twenty-four rats were randomized into two groups, to receive either a normal diet (ND) or HFD for 12 weeks. Then, rats in each group was further subdivided into two subgroups (n= 6/subgroup) and each subgroup was treated with either vehicle (V) or probiotics (PO; Lactobacillus paracasei ST11 HP4 1 x 109 CFU), for other 12 weeks. Blood sampling, were collected at week 12 and at the end of week 24. Jaw bone density will be measured. Bone marrow will also be collected to evaluate inflammation and oxidative stress