Study On The Effect Of NAC On The Survival Rate Of Autologous Fat Transplantation

[Background]In recent years,autologous fat transplantation(AFT)has been used more and more in the repair of soft tissue defect and cosmetic surgery.For the advantages of no immune rejection,easily accessible and convenient operation,autologous adipose tissue has become a kind of excellent filling material.But the high absorption rate due to the uncertain effect of the operation to limit its application.From the many years study,It has been found that the transplanted fat cells are in the environment of ischemia and hypoxia before the reconstruction of vascular network,It is easy to induce cell apoptosis and necrosis.Therefore,how to accelerate the revascularization process and inhibit the apoptosis and necrosis is the key point to improve the survival rate of autologous fat transplantation.Because of its significant role in antioxidation and inhibition of apoptosis in cells,N-acetyl-L-cysteine(NAC)has been used more and more in organ transplantation,myocardial ischemia reperfusion injury and so on.NAC can inhibit the apoptosis of many kinds of cells,so we think whether it can also inhibit the apoptosis of transplanted adipose cells and increase the survival rate of autologous fat transplantation.The aim of this study was to determine the effect of NAC on the survival rate of autologous fat transplantation and to explore its possible mechanism.[Objective]1.To determine the changes of adipose tissue after autologous fat transplantation.2.To determine whether NAC can improve the survival rate of autologous fat transplantation.3.Explore the mechanisms by which NAC functions.[Methods and Results]1.Changes of adipose tissue after fat transplantation:Method:Extract adipose tissue in the groin from the healthy adult female SD rats,processed into fat particles and then injected into the subcutaneous.After 2 weeks,4 weeks,6 weeks and 8 weeks,the volume and histological changes of adipose tissue were observed by gross observation,volume measurement and HE staining.Result:Transplantation of adipose tissue with the passage of time,the volume becomes smaller,the color gradually darken,hard texture,transplantation of adipose tissue around 2 weeks began to appear in connective tissue envelope has been maintained to 8 weeks,with the emergence of a large number of coated,fat cells and new blood vessels begin to form,and gradually formed a fibrous septum,8 weeks note the amount of intact mature fat cells,at the same time with formation of new blood vessels.The area around the fat cells has always maintained a good growth,angiogenesis also from the surrounding area began to grow to the central direction,the central area of the 2 week when most cells had formed a large number of necrosis,necrotic cavity,no mature fat cells.2 The effect of NAC on the survival rate of AFT:Method:Extract adipose tissue in the groin from 20 healthy adult female SD rats,extracted into lml fat granule,divided into two groups of rats were injected into the subcutaneous back,left side of the experimental group,0.5ml injection of adipose tissue +0.5ml concentration of the injected of 60 mol/L NAC,the right side of the control group,0.5ml injection of adipose tissue+0.5ml NS.Respectively after 2 weeks,4 weeks,6 weeks and 8 weeks were collected,through gross observation,volume measurement,HE staining,CD31 staining and other methods to evaluate the transplantation of adipose tissue volume,survival rate,fat cells,neovascularization,confirmed the survival of NAC effect on AFT.Result:The two groups of transplanted adipose tissue showed a decrease in volume with time,the volume measurement showed that all experimental groups were higher than the control group.The results showed that the number of cells in the experimental group was higher than that of the control group in all time periods,and the morphology,integrity and arrangement of the cells in the experimental group were better than those in the control group.The results show the blood vessel count all the time the number of blood vessels in the experimental group than the control group,two groups of blood vessels from less to more,and the formation of vascular network surrounding the transplanted tissue,angiogenesis was developed by surrounding area to central area.3.Study on the mechanism of NAC with AFT:Methods:To explore the possible mechanism of NAC to improve the survival rate of AFT by the rate of apoptosis and the level of intracellular ROS.Using Annexin V/PI double staining method in the treatment of fat cells,flow cytometry,clear experimental group and control group,apoptosis of transplanted fat cells;fat cells by DCFH-DA staining,flow cytometry,clear fat cells in the level of ROS.The effect of NAC on the apoptosis rate and the level of intracellular ROS was determined by statistical analysis.Result:The results showed that the apoptosis rate of the experimental group was lower than that of the control group,and with the passage of time,the apoptosis rate decreased gradually and tended to be stable.The results showed that the ROS level in the experimental group was lower than that in the control group,the level of ROS increased gradually with the passage of time,but the increase of the experimental group was significantly lower than that of the control group.[Conclusion]1 The transplanted adipose tissue decreased with time,the color became dark,and there were connective tissue capsule wrapped around the body,the fat cells were regenerated and gradually stabilized.2 NAC can preserve the transplanted adipose tissue,promote the regeneration of fat cells and the growth of new blood vessels.3 NAC can reduce the level of ROS in adipocytes and decrease the rate of apoptosis.4 NAC can increase the survival rate of transplanted fat and accelerate the process of transplantation.