Nuclear receptors are transcriptional regulators involved in almost all biological processes such as cell growth, differentiation, apoptosis, substance metabolism and tumor formation, and they can be regulated by small molecules that bind to them. Autophagy is a special way of programmed cell death and it is a highly conserved metabolic process. Once autophagy defects or excessive autophagy occur, the disease will develop. In recent years, numerous studies have shown that nuclear receptors are related to autophagy. Therefore, this paper mainly reviews the research progress on nuclear receptors involved in the regulation of autophagy, and focuses on the mechanism of several nuclear receptors involved in the regulation of autophagy, aiming at understanding the molecular basis of how nuclear receptors participate in regulating autophagy, as well as providing possible ideas and strategies for the treatment of corresponding diseases.
【Abstract】 Objective To evaluate the effect on repairing composite defect of mandible and skin by pre fabricatedmusculocutaneous flap including ectopic bone induced by BMP-2 and collagen in rabbits’ latissimus dorsimuscle. Meth ods Twenty-four rabbits (4-6 weeks old) were randomly divided into 3 groups: experimental, control and blank control group (n=8 in each group). Composite carriers composed of BMP-2 and collagen I sponge were implanted into latissimus dorsi muscle pouches of rabbits. The bone formation was evaluated with roentgenography, ALP staining, Von Kossa staining, HE staining, toluidine blue staining and CD31 immunohistochemical labell ing of microvessels. After 6 weeks, the mandibular defect of 8 mm in diameter with local skin defect of 2 cm × 3 cm was made in experimental group, and a musculocutaneous flap including ectopic-induced bone was prefabricated to transfer and repair the composite defect. The mandibular defect of 8 mm in diameter without local skin defect was made in control and blank control group. Free ectopic-induced bone was used for the repair of mandibular defect in control group, but repairing was not performed in blank control group. All the samples were detected 6 weeks after operation for tetracycl ine fluorescent staining, X-ray, histological examination and bone quantity analysis to evaluate the effect. Results Bone formation induced by BMP-2/collagen composites were found as woven bone between 4 to 6 weeks. It showed that cartilaginous osteogenesis was the mainly type of bone formation. Microvessels could beseen in the bony tissues. The composite defects of mandible and skin were healed well in the experimental group. Major bony tissue were seen in the control group, while it still remained bony defect in the blank control group. The bone quantity analysis in the experimental, control, and blank control group were (1.594 ± 0.674), (0.801 ± 0.036), and (0.079 ± 0.010) mm2, there were significant differences between each groups (P lt; 0.05). Conclusion Prefabrication of musculocutaneous flap including boneinduced by the composite of BMP-2 and collagen is feasible and prevalent. It can be regarded as vascularized bone graft and used in repairing composite defect of bone and skin.
