Abstract: Objective: To evaluate the effect of 14, 15 epoxyeicosatrienoic acid (14, 15-EET) on the healing of calvarial defect in C57BL / 6 mice. Methods: A 5-mm diameter calvarial critical-sized defect was created on each side of the calvarial bone of the C57BL / 6 mice. The calvarial defects were allocated into experimental group (right sides) and control group (left sides). BMSCs pretreated with 14, 15-EET (1 μmol/L, experimental group, n =10) or untreated with 14, 15-EET (control group) were implanted into bone defects. 14, 15-EET (10 μmol/L, experimental group) or PBS (control group) was administered by subcutaneous injection in calvarial defect area every other day from third post-operative day for four weeks. Mice were sacrificed at 8th post-operative week. Bone regeneration in the calvarial defect area was assessed with CBCT. HE and Masson's trichrome stain were performed to assess the newly formed blood vessels and connective bone tissues. Results: Compared with the control sides, the area of bone defect in the experimental sides treated with 14, 15-EET was obviously decreased at 8th post-operative week (P<0.05). 14, 15-EET treatment increased blood vessels and bone formation of the experimental sides when compared to the control sides at 8th post-operative week (P<0.05). In addition, there were more osteoid and collagen fibers in the defect area treated with 14, 15- EET. Conclusion: 14, 15-EET may promote bone regeneration through improvement of local microcirculation.

Key words: 14,15-epoxyeicosatrienoic acid , Bone defect, Bone regeneration