OBJECTIVETo observe the effect of acupuncture on fracture in the ovariectomized rat and the mechanism.

METHODSSixty SD female rats were randomly divided into 4 groups: normal group (group A), model group (group B), acupuncture group (group C) and Nilestriol group (group D). In all the groups, except the group A which received sham operation, the rats were overiectomized for preparing the osteoporosis model. Three months after the ovariectomy, the left femurs of the rats were closely fractured. Then, the group A and B were treated with oral administration of normal saline solution, 3 mL, weekly. The rats in the group C were treated daily with acupuncture at "Huantiao"(GB 30), "Housanli" (ST 36), "Yanglingquan"(GB 34) and "Weizhong"(BL 40) on the left hind legs; the rats in the group D were given orally Nilestriol solution (0.2 mg/mL) in a dose of 0.6 mL/100 g body weight, weekly. At the 7th, 14th, 21st and 28th days, some rats were sacrificed and their fractural callus and blood samples were taken for histological examinations and immunohistochemical examination of brain-derived neurotrophic factor (BDNF) and tyrosine kinase B (TrkB).

RESULTSHE stained callus slides observed by optical microscope showed that the process of fracture healing in the group A, C, D was faster than that in the group B. Positive immuno-stalning of BDNF and TrkB could be seen in the all groups, mainly on the 7 and 14 days after the fracture. The expression levels from high to low in turn were group A, C, D and B.

CONCLUSIONExpressions of BDNF and TrkB in callus of osteoporotic fracture were less than that of the normal fracture; acupuncture can elevate the expression levels and accelerate the process of fracture healing.