ABSTRACT
BACKGROUND:There are many postmenopausal women taking hormone, which leads to much loss of bone mass, further inducing fragility fractures. The studies on the hormone exposure combined with ovariectomy-induced osteoporotic model are still immature, and the related molecular mechanism remains unclear. OBJECTIVE: To establish the rat osteoporotic model induced by ovariectomy combined with glucocorticoid exposure and to explore the underlying molecular mechanism. METHODS: Thirty 3-month-old female Sprague-Dawley rats were randomly divided into blank control, sham and model groups (n=10 per group). The rats in the blank control group received no intervention; rats in the sham group were clipped off a little of coeliac adipose tissue; the model rats received bilateral ovariectomy and 4-week administration of glucocorticoid. RESULTS AND CONCLUSION:At 4 weeks after modeling, compared with blank control and sham groups, the model group showed significantly lower bone mineral density of the femur, number of bone trabeculae and bone volume/total volume, and significantly wider bone trabecular spacing. Additionally, the model group revealed the damaged bone trabecular structure and thiner cortical bone. The expression level of Runx2 was downregulated whereas both collagen type 1α1 and peroxisome proliferators activated receptor γ mRNA were upregulated in the model group. These findings suggest that ovariectomized rats exposed to glucocorticoid rapidly develop femur osteoporosis, maybe by downregulating the expression of Runx2, as well as upregualting collagen type 1α1 and peroxisome proliferators activatedreceptor γ mRNA.
ABSTRACT
BACKGROUND: It is a hotspot that calcium phosphate and calcium sulphate as the main ingredients are combined with one or more other materials to improve or increase the performance of bone tissue engineering scaffolds. OBJECTIVE: To introduce the research advance of these two kinds of scaffolds in bone tissue engineering. METHODS: The articles related to the bone tissue engineering published during January 2000 to June 2015 were retrieved from CNKI and PubMed databases by computer. The key words were “bone tissue engineering, scaffold, calcium phosphate, calcium sulphate, vascularization” in Chinese and English, respectively. ESULTS AND CONCLUSION: Calcium phosphate and calcium sulfate are characterized as having good biocompatibility, biodegradability, osteoconductivity and complete bone substitutability. However, single use of calcium phosphate or calcium sulfate scaffold has certain disadvantages, both of which are difficult to ful y meet the requirements of the bone defect repair. Improvement can be acquired in the mechanical strength, injectability and biodegradability, as wel as drug-loading and pro-angiogenesis of the scaffold in combination with other materials. In the basal and clinical research, we should explore and develop ideal scaffolds in on the basis of therapeutic aim. However, most of the scaffold studies are stil at the extracorporeal and animal experiment stage, and the comparative studies on composite scaffolds and optimal proportion of those composite scaffolds stil need to be further investigated.