Annatto-extracted tocotrienols improve glucose homeostasis and bone properties in high-fat diet-induced type 2 diabetic mice by decreasing the inflammatory response

Sci Rep. 2018 Jul 27;8(1):11377. doi: 10.1038/s41598-018-29063-9.

Abstract

Diabetes is a risk factor for osteoporosis. Annatto-extracted tocotrienols (TT) have proven benefits in preserving bone matrix. Here, we evaluated the effects of dietary TT on glucose homeostasis, bone properties, and liver pro-inflammatory mRNA expression in high-fat diet (HFD)-induced type 2 diabetic (T2DM) mice. 58 male C57BL/6 J mice were divided into 5 groups: low-fat diet (LFD), HFD, HFD + 400 mgTT/kg diet (T400), HFD + 1600 mgTT/kg diet (T1600), and HFD + 200 mg metformin/kg (Met) for 14 weeks. Relative to the HFD group, both TT-supplemented groups (1) improved glucose homeostasis by lowering the area under the curve for both glucose tolerance and insulin tolerance tests, (2) increased serum procollagen I intact N-terminal propeptide (bone formation) level, trabecular bone volume/total volume, trabecular number, connectivity density, and cortical thickness, (3) decreased collagen type 1 cross-linked C-telopeptide (bone resorption) levels, trabecular separation, and structure model index, and (4) suppressed liver mRNA levels of inflammation markers including IL-2, IL-23, IFN-γ, MCP-1, TNF-α, ITGAX and F4/80. There were no differences in glucose homeostasis and liver mRNA expression among T400, T1600, and Met. The order of osteo-protective effects was LFD ≥T1600 ≥T400 = Met >HFD. Collectively, these data suggest that TT exerts osteo-protective effects in T2DM mice by regulating glucose homeostasis and suppressing inflammation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Biomarkers / blood
  • Bixaceae
  • Blood Glucose / metabolism*
  • Body Weight
  • Bone Remodeling / drug effects
  • Bone and Bones / drug effects
  • Bone and Bones / metabolism*
  • Carotenoids / pharmacology*
  • Diabetes Mellitus, Experimental / pathology*
  • Diabetes Mellitus, Type 2 / pathology*
  • Diet, High-Fat
  • Feeding Behavior
  • Homeostasis* / drug effects
  • Inflammation / pathology*
  • Liver / drug effects
  • Liver / metabolism
  • Male
  • Mice, Inbred C57BL
  • Pancreas / drug effects
  • Pancreas / pathology
  • Plant Extracts / pharmacology*
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Tocotrienols / pharmacology*
  • Water

Substances

  • Biomarkers
  • Blood Glucose
  • Plant Extracts
  • RNA, Messenger
  • Tocotrienols
  • Water
  • Carotenoids
  • annatto