| BackgroundThe breast has an important influence on the appearance of women.However,because of congenital dysplasia,breast feeding,aging,or malignant tumors,women’s breasts become small,sagging,poor appearance,and even lack of breasts,which seriously affect the appearance of the body,and even make women lack of psychological self-confidence.Breast plastic surgery includes flap transplantation,prosthesis implantation,soft tissue filling,in which autologous fat is used as soft tissue filler and has many advantages,such as wide source,easy access,biocompatibility,and minimal trauma.It is widely used in the field of breast plastic surgery.However,fat cells are high energy consumption,when ischemia and hypoxia,the fat cells fail to obtain adequate nutrient supply,will lead to fat necrosis.These problems limit the application of autologous fat transplantation in the field of breast plastic surgery.In 1987 the American Society of Plastic Surgeons even interfered with the diagnosis of breast tumors because of fat necrosis and calcification.For a time,the American Society of Plastic Surgery had banned women for autologous fat grafting.With the advancement of fat transplantation technology and the development of imaging diagnostic technology,the American Society of Plastic Surgery announced in 2009 no longer forbidden to prohibit autologous fat transplantation for breast augmentation,but it still did not recommended.In recent years,with the development of autologous fat transplantation technology,this operation has great achievements.However,with the wide application of autologous fat transplantation breast augmentation,complications such as fat liquefaction,necrosis,and palpable nodules after surgery have attracted patients’ attention.How to reduce these complications has become an urgent problem to be solved.In long-term clinical practice,we found that the composition and distribution of oil in transplanted fat may be the main factor leading to the occurrence of postoperative nodules.This study was designed and carried out for this purpose.Objective1.To investigate the correlation between postoperative fat necrosis after breast augmentation and fat purification process.2.Compare the quality of fat grafts between centrifugation and sedimentation3.Compare the quality of fat grafts at different levels after centrifugation;4.To compare the effect of different oil content on the quality of fat graft survival;Methods1.Correlation between postoperative complications and fat purification of autologous fat transplantation breast augmentationPatients undergoing autologous fat transplantation breast augmentation using different fat purification methods were randomly divided into a sedimentation group and a centrifuge group.All patients underwent breast examination and breast color ultrasonography before operation three months after operation.The complications of fat necrosis after autologous fat transplantation were compared.2.Comparison of different fat purification methods on grafts survival qualityThe free fat particles were centrifuged at 800 rpm for 3 min to remove the lower layer of water to obtain purified fat.The free fat was allowed to stand for 15 minutes to remove the lower layer of water,and the purified fat was obtainedIn vitro:High-speed(3000 rpm)fats were centrifuged for 3 min in each group to measure the proportion of free oil;the histological and immunochemical examinations were performed to compare the cell integrity of the adipose tissues;Type Ⅰ collagenase Stromal Vascular Fractions(SVFs)in adipose tissue were obtained by digestion and counted by trypan blue staining to compare the number of SVF cells.In vivo experiments:Animal fat graft animal models were constructed using nude mice.Each group of fat grafts was injected subcutaneously into the back of nude mice,and the graft specimens were collected 4 weeks after transplantation.The survival of grafts in each group was compared by weighing;the necrosis and fibrosis of grafts were compared by HE staining;the cell integrity of grafts was compared by perilipin immunohistochemical staining;the angiogenesis of grafts was compared by CD31 immunohistochemical staining;Graft inflammation in Macrophages compared with Mannose-R immunohistochemistry3.Comparison of survival quality of different layered fat grafts after centrifugation After the free fat particles were centrifuged at a low speed,the bottom moisture were removed to obtain purified fat.According to the level,fat is divided into three equal parts,respectively,the upper layer,the middle layer,and the lower layer;and the centrifugation fat mechanical mixing as a control group.In vitro:The fat of each group were subjected to high speed centrifugation to measure the content of oils.The structure and integrity of the adipose tissues were compared by histological examination;the Stromal Vascular Fraction(SVFs)in adipose tissue was obtained by digestion with type I collagenase,counting with Trypan Blue,compares the number of SVF cells.In vivo experiments:Fat graft animal models were constructed using nude mice.Each group of fat grafts was injected subcutaneously on the back of nude mice,and graft specimens were collected 4 weeks after transplantation.The fat grafts were compared by weight;the grafts were compared for liquefaction necrosis and fibrosis by HE staining;the cell integrity of fat grafts was compared by perilipin immunohistochemical staining;the groups were compared by CD31 immunohistochemical staining.The neovascularization of fat grafts was performed.Mannose-R immunohistochemical staining was used to compare the inflammatory infiltration of fat graft macrophages in each group.4.Effects of different fat content on the quality of fat graft survivalAfter the high-speed centrifugation of the free fat grafts,the oil is obtained,and the fat is added into the centrifugal purified fat in different proportions,which are:centrifugation +1/3 oil,centrifugation + 2/3 oil,pure oil;and the fat graft is mechanically mixed after centrifugation as a control group.In vivo experiments:All groups of fat grafts were injected subcutaneously on the back of nude mice,and the graft specimens were collected 4 weeks after transplantation.The fat grafts were compared by weight;and the liquefaction necrosis and fibrosis compared by HE staining;the cell integrity of fat grafts was compared by perilipin immunohistochemical staining;the groups were compared by CD31 immunohistochemical staining.The neovascularization of fat grafts was performed.Mannose-R immunohistochemical staining was used to compare the inflammatory infiltration of fat graft macrophages in each group.Results1.A total of 167 breasts in this study,including 77 in the centrifuge group and 90 in the sedimentation group;the incidence of fat necrosis and palpable nodules in the centrifuge group was higher than that in the sedimentation group(P<0.05);The more times of the autologous fat augmentation surgery,the higher incidence of nodules after surgery;the incidence of postoperative breast nodules in patients with a history of breast surgery was higher than those without a history of breast surgery.2.There was no significant difference in cell integrity between the centrifugation group and the sedimentation group;the number of SVF cells in the centrifuge group was higher than that in the sedimentation group(P<0.05),and there was no difference in oil content between two group;The weight of specimens in the centrifuge group was higher than that in the sedimentation group;necrosis,liquefaction,and fibrosis in the specimens of the centrifuge group were significantly higher than those in the sedimentation group(P＜0.05);perilipin-positive cells in the fat graft of the centrifuge group was no significant difference between the sedimentation group;the number of neovascularization in the centrifuged group was greater than that in the sedimentation group(P＜0.05);the macrophage infiltration of fat grafts in the centrifuge group was more significant than that in the resting group(P＜0.05).3.There was no significant difference in cell integrity between the upper,middle,and lower layer fat grafts.Compared with the control group,the oil was higher in the upper layer fat graft,the number of SVF cells was lower(P＜0.05);and the lower layer contents less oil,but SVF cells number was high(P＜0.05).There was no significant difference in cell number and oil between the mid-layer fat grafts and the control group;samples were taken at 4 weeks post-transplantation,and the weight of the upper graft specimens was low.In the control group,the weight of the low-layer fat graft was higher than that of the control group(P＜0.05).The weight of the middle fat graft was not statistically different from that of the control group;necrosis and liquefaction of the upper layer graft were observed.Fibrosis and fibrosis were significantly higher than those in the other three groups(P＜0.05).Perilipin positive cells in the upper fat graft were lower than those in the control group(P＜0.05).No significant difference was observed between the other two groups and the control group.Difference;the number of neovascularization was lower in low-layer grafts than in the control group(P＜0.05).The number of neovascularization was lower in the upper and middle layer than in the control group.(P＜0.05);Infiltration of macrophages in the upper fat graft of the centrifuge group was significantly greater than that of the control group,and there was no significant difference between the other two groups and the control group.4.After 4 weeks of grafting,the grafts were weighed and compared:centrifugal group＞centrifugus+1/3 oil group＞centrifugal+2/3 oil group＞pure oil group,the difference was statistically significant(P＜0.05);In terms of necrosis,liquefaction and fibrosis,the concentrations of centrifugation plus 1/3 oil,centrifugation plus 2/3 oil and oil alone were higher than those of the centrifuge group(P ＜ 0.05),and the higher the oil content,the greater of necrosis and liquefaction after transplantation.Obviously,the number of perilipin positive cells in the centrifuge group was higher than that in the centrifugal ＋1/3 oil group and the centrifugal +2/3 oil group(P ＜ 0.05).No perilipin stained positive cells were found in the oil group.Novascularization in the oil group of centrifugation +1/3 oil,centrifugation +2/3 oil group,and simple oil group were lower than centrifuge group(P<0.05);Macrophages in the centrifugation +1/3 oil group,centrifugation +2/3 oil group,and oil group fat graft were infiltration of cells was more obvious than centrifuge group.Conclusions1.The incidence of breast nodules in low centrifugation group is higher than sedimentation method.The incidence of nodules after autologous fat grafting increased with the number of surgeries;the incidence of breast nodules was higher than patients without history of surgery.2.There was no significant difference in cell integrity and fat content between fat grafts and centrifugation.However,the SVF cell content was higher than that of the sedimentation method.The weight of the centrifuged adipose tissue was better and neovascularization was observed,but fat liquefaction,fibrosis,and inflammatory infiltrates were higher than in sedimentation groups.3.After centrifugation,the upper layer of the fat graft position,the more oil contents and the lower SVF cells.The lower of the fat graft position,the more liquefaction necrosis as well as macrophage inflammatory infiltration.4.The more oil in fat grafts,the smaller weight of specimens after transplantation,the less of neovascularization,and the more obvious inflammatory necrosis and macrophage inflammation infiltration. |
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