| BackgroundsFemoral head necrosis is a disorder of the blood supply of the femoral head caused by various causes,which leads to ischemic necrosis of bone cells and bone marrow components,and then self-repairs,ultimately resulting in structural changes,collapse,and joint dysfunction of the femoral head.Studies have shown that there are about 20 million patients with femoral head necrosis in the world,and there are about 100,000200,000 new cases of femoral head necrosis in my country each year.In recent years,a research survey on the etiology of femoral head necrosis indicated that the number of patients with idiopathic femoral head necrosis in China accounted for 28.71%of the total number of patients with femoral head necrosis.Hormones play an irreplaceable role in the treatment of many diseases,but a large number of irregular use of hormones will also produce serious complications,such as steroid-induced avascular necrosis of the femoral head(SANFH)),the current research shows that hormone-induced femoral head necrosis has become the main type of non-traumatic femoral head necrosis.Femoral head necrosis has a high disability rate.If patients with femoral head necrosis do not receive early intervention or treatment,large-scale collapse and necrosis of the femoral head will develop in the late stage,causing severe pain and difficulty walking.It is not only for femoral head replacement,but more or less.It will leave lower limb movement or sensory function decline,leaving sequelae,patients with poor results and even leaving disabilities,which brings a huge burden to patients and society.Therefore,the early diagnosis and treatment of femoral head necrosis is particularly important.The pathogenesis of hormone-induced femoral head necrosis is different.The pathogenesis theories are as follows:intravascular coagulation theory,lipid metabolism disorder theory,apoptosis theory,bone marrow mesenchymal stem cell differentiation theory,osteoporosis theory,The theory of intraosseous hypertension,etc.At present,it is believed that hormone-induced femoral head necrosis is the result of a combination of many factors.Therefore,improving the local blood circulation of the femoral head,promoting bone formation,improving the coagulation state,regulating lipid metabolism,and inhibiting cell apoptosis have an effect on the process of early hormone-induced femoral head necrosis.The suppression or reversal of the situation is of great significance.Ghrelin is a 28-amino acid polypeptide molecule extracted from the stomach of mice.Many of its physiological functions are mainly mediated by growth hormone secretagogue receptor 1a(GHSR 1a)and thus exert biological effects.In addition to being expressed in the stomach,Ghrelin can also be expressed in many tissues such as the duodenum,jejunum,ileum,colon,lung,heart,pancreas,kidney,testis,pituitary gland,and hypothalamus.The evidence that has been read more and more in recent years has shown that in addition to the important role of Ghrelin in regulating the body's energy metabolism,its role in the regulation of bone and cartilage metabolism,immunity and inflammation is gradually being recognized,and it plays an important role in the metabolism of bone and cartilage.effect.However,there are still few studies on the role of Ghrelin in steroid-induced femoral head necrosis,and its influence on steroid-induced femoral head necrosis and its possible mechanism are not very detailed.Vascular Endothelial Growth Factor(VEGF)is a homodimeric glycoprotein connected by disulfide bonds or non-covalent bonds.It has the most powerful effect on promoting blood vessel formation and is the most important angiogenic factor in the body.It stimulates endothelial cells,osteoblasts and hematopoietic cells in a paracrine way to regulate the activity of osteoblasts,and directly affects the function of osteoblasts through an autocrine mechanism.Bone morphogenetic protein(Bone Morphogenetic Proteins,BMP)is a signal molecule that promotes bone regeneration.BMP2 has the highest osteoinductive activity,can highly promote bone formation and expression,and can promote the secretion and production of specific bone cell products,Promote transcription factors Runx2 and Osx through Smads or MAPK two ways to promote osteoblast-specific gene expression.Bone Marrow-mesenchymal Stromal Cells(BMSCs)are another type of stem cells with self-renewal and multi-differentiation potential in addition to hematopoietic stem cells in the bone marrow.Their main directions of differentiation are osteogenic differentiation and adipogenic differentiation It can not only differentiate into fat cells,muscle cells and fibroblasts,but also into bone cells and chondrocytes.At present,many research results suggest that the subtype PPARy2 in the family of Peroxisome Proliferators Activated Receptors(PPAR),as a nuclear receptor,can regulate the transformation of BMSCs from bone cells to adipocytes,thereby inhibiting the transformation of BMSCs from bone cells to adipocytes.Bone formation,enhance bone marrow fat production.Runx,or runt-related transcription factor 2(Runx2),plays the most significant role in the regulation of bone metabolism.Runx2 plays a key role in the differentiation of osteoblasts and may be closely related to the BMP2/Smads/Runx2/Osterix signaling pathway.In summary,can Ghrelin affect the progression of hormonal femoral head necrosis?Is it possible to improve hormonal necrosis of the femoral head by regulating the expression of VEGF and BMP2?Can it play an important regulatory role in the differentiation of BMSCs into osteogenesis or adipogenesis?Based on the above research background,this experiment first carried out in vivo experiments.By constructing a rabbit hormone-induced femoral head necrosis model,after Ghrelin intervention,the histopathological changes of femoral head,serum lipid changes,and the expression of VEGF and BMP2 in femoral head tissue were inferred.The effect of Ghrelin on hormone-induced osteonecrosis of the femoral head and its possible mechanism;in vitro experiments observed the effect of Ghrelin on the expression of BMP2,Runx2,PPAR?2 protein and mRNA in BMSCs cells,and the effect on the expression of VEGF in the cell supernatant,which comprehensively proved that Ghrelin has different differentiation of BMSCs The influence of direction and possible mechanism further proves the influence and possible mechanism of Ghrelin on hormone-induced femoral head necrosis.Contents1.In vivo experiment part:Ghrelin's effect on rabbit steroid-induced femoral head necrosis and its possible mechanism.2.In vitro experiments:the effect of Ghrelin on the differentiation of BMSCs and its possible mechanism.Methods1.The effect of Ghrelin on rabbit steroid-induced avascular femoral head necrosis and its possible mechanism.In vivo experiments used methylprednisolone combined with horse serum to build a rabbit model of hormone-induced femoral head necrosis.The successfully modeled New Zealand rabbits were divided into a control group and an intervention group.Ghrelin was given to intervene,serum and femoral head tissue were collected,and each group was tested.Serum triglycerides,total cholesterol,lowdensity lipoprotein,high-density lipoprotein levels,imaging changes,histopathological changes of the femoral head,and the expression of VEGF and BMP2,to explore the effect of Ghrelin on rabbit steroid-induced femoral head necrosis and Possible mechanism.2.The effect of Ghrelin on the differentiation of BMSCs and its possible mechanism.In vitro experiments were carried out by culturing bone marrow mesenchymal stem cells and applying Ghrelin at an appropriate concentration in the cell culture medium.After overnight incubation,RT-PCR was used to detect the expression of BMP2,Runx2 and PPAR?2 mRNA in the cells;Western Blot was used to detect the expression of BMP2,Runx2 and PPAR?2 in the cells.Expression;Elisa detects the expression of VEGF in the cell supernatant and compares it with the control group in order to explore the effect of Ghrelin on the different differentiation directions of bone marrow mesenchymal stem cells and its possible mechanism.Results1.The effect of Ghrelin on rabbit steroid-induced femoral head necrosis and its possible mechanism.(1)General condition and weight change:New Zealand rabbits in the normal group have shiny hair,more sensitive activities,and good appetite.The shape of the model is gradually becoming thinner,the hair is dry and dull,the subcutaneous fat becomes thinner,the bounce distance is short when the rabbit moves,the hind limbs are awkward,and the height is reduced.The weight of the normal group has been increasing,and the weight of the model group has decreased after injection of horse serum.The weight of the Ghrelin intervention group has increased significantly faster than the control group.(2)Magnetic resonance examination is used to determine whether the hormone combined with horse serum is successful.In the normal group,the femoral head showed patchy T1,the T2 signal was normal,and there was no fluid signal in the hip joint cavity;the control group saw patchy long T1,long T2 abnormal signals,and the visible fluid signal in the hip joint cavity was stronger than the normal group;Ghrelin intervention In the group,there was a patchy long T1,and a slightly longer T2 abnormal signal,and the signal of joint cavity effusion was slightly higher.(3)In the normal group of histopathology,chondrocytes and levels were normal,and hollow bone depressions were rare.A large number of hematopoietic cells can be seen in the medullary cavity,and the fat ratio is normal.In the control group,bone trabecula was widely sparse and fractured,and flaky hollow bone depressions were seen in the cartilage area;hematopoietic cells were extensively damaged.Ghrelin intervention group showed hypertrophy of chondrocytes,nucleus in the center,more fat cells,sparse bone trabeculae,occasionally broken,and slightly hypertrophy of fat cells,which accounted for more than normal bone marrow,without fusion.The model shows that chondrocytes are arranged in disorder,the nucleus is concentrated,and the number of hollow bone depressions increases.The bone trabecula is sparse and thin,and fat cells increase and enlarge,and some of them fuse into bubbles.(4)Serum lipid detection The levels of total cholesterol,triglycerides,and lowdensity lipoproteins in the Ghrelin intervention group were significantly lower than those in the control group,and high-density lipoproteins were higher than those in the control group.The levels of total cholesterol,triglycerides,and low-density lipoproteins in the Ghrelin intervention group were significantly lower The levels of lipoprotein and high-density lipoprotein were not much different from those in the normal group.(5)Expression of VEGF mRNA and BMP2 mRNA in femoral head tissue.The expressions of VEGF mRNA and BMP2 mRNA in the Ghrelin group were significantly higher than those in the control group and the blank group,and the expressions of VEGF mRNA and BMP2 mRNA in the control group were higher than those in the blank group.2.The effect of Ghrelin on the differentiation direction of BMSCs and its possible mechanism(1)Western blot detection of BMP2,Runx2 and PPARy2 protein expression in the cells of the Ghrelin intervention group and the control group showed that the expression of BMP2 in the Ghrelin intervention group was significantly higher than that of the control group,and the expression of Runx2 in the Ghrelin intervention group was significantly higher than that of the control group;PPAR?2 in the control group The expression of Ghrelin was higher than that of the Ghrelin intervention group.(2)RT-PCR detection of the expression of BMP2mRNA,Runx2mRNA and PPARy2 mRN A in the cells of the Ghrelin intervention group and the control group showed that the expression of BMP2 mRNA in the Ghrelin intervention group was significantly higher than that of the control group;the expression of Runx2 mRNA in the Ghrelin intervention group was significantly higher than that of the control group;The expression of PPAR?2mRNA in the control group was higher than that of the Ghrelin intervention group.(3)Elisa detected the expression of VEGF in the cell supernatant,and found that the expression of VEGF in the Ghrelin intervention group was significantly higher than that in the control group.Conclusion1.Ghrelin can improve the lipid metabolism and pathological manifestations of early rabbit hormone-induced femoral head necrosis,and delay the process of early rabbit hormone-induced femoral head necrosis.2.Ghrelin promotes the angiogenesis and bone formation of early hormonal femoral head necrosis in rabbits by promoting the expression of VEGF and BMP2.3.Ghrelin can promote osteogenic differentiation and inhibit adipogenic differentiation by promoting the expression of BMP2,Runx2,and VEGF,inhibiting the expression of PPAR?2 in BMSCs. |
PDF Full Text Request