RESUMO
Determination of lipid droplet (LD) volume has depended on direct measurement of the diameter of individual LDs, which is not possible when LDs are small or closely apposed. To overcome this problem, we describe a new method in which a volume-fluorescence relationship is determined from automated analysis of calibration samples containing well-resolved LDs. This relationship is then used to estimate total cellular droplet volume in experimental samples, where the LDs need not be individually resolved, or to determine the volumes of individual LDs. We describe quantitatively the effects of various factors, including image noise, LD crowding, and variation in LD composition on the accuracy of this method. We then demonstrate this method by utilizing it to address a scientifically interesting question, to determine the density of green fluorescent protein (GFP)-tagged Perilipin-Adipocyte-Tail (PAT) proteins on the LD surface. We find that PAT proteins cover only a minority of the LD surface, consistent with models in which they primarily serve as scaffolds for binding of regulatory proteins and enzymes, but inconsistent with models in which their major function is to sterically block access to the droplet surface.
Assuntos
Processamento de Imagem Assistida por Computador/métodos , Gotículas Lipídicas/ultraestrutura , Microscopia Confocal/métodos , Perilipinas/análise , Técnicas de Cultura de Células/métodos , Transferência Ressonante de Energia de Fluorescência/métodos , Proteínas de Fluorescência Verde/análise , Células HeLa , Células Hep G2 , Humanos , Gotículas Lipídicas/química , SoftwareRESUMO
PURPOSE: To evaluate the feasibility of an experimental model of autologous fat graft (AFG) in different interstitial pressure (IP) environments. METHODS: Three mini-pigs(Minipig-BR) with age of 8 months (weight: 25-30 kg) were used. AFG were collected from the bucal fat pad, and grafted in the intramuscular pocket (biceps femoralis muscle). IP model was based on a fusiform ressection followed by primary closure "under tension". A blood pressure catheter located in the intramuscular region connected to a pressure module was applied to quantify IP. RESULTS: The mean operative time was 236 min (210 - 272 min). All the AFG and muscular segments were removed successfully. Average interstitial pressure CP and H were 3 and 10.6 mmHg respectively. The AFG were biopsied for histopathological analysis 30 days after graft. Hematoxylin-eosin staining and immunohistochemical analyzes (TNF-alpha, CD31 and Perilipine with monoclonal antibodies) were employed. CONCLUSION: The data show that minipigs model could be used as a recipient site for autologous fat graft techniques and allow the development of studies to explore the AFG intake and pathophysiology response.
Assuntos
Tecido Adiposo/transplante , Modelos Animais de Doenças , Procedimentos de Cirurgia Plástica/métodos , Transplante Autólogo/métodos , Animais , Estudos de Viabilidade , Sobrevivência de Enxerto , Imuno-Histoquímica , Masculino , Perilipinas/análise , Molécula-1 de Adesão Celular Endotelial a Plaquetas/análise , Pressão , Procedimentos de Cirurgia Plástica/normas , Suínos , Porco Miniatura , Transplante Autólogo/normas , Fator de Necrose Tumoral alfaRESUMO
Abstract Purpose: To evaluate the feasibility of an experimental model of autologous fat graft (AFG) in different interstitial pressure (IP) environments. Methods: Three mini-pigs(Minipig-BR) with age of 8 months (weight: 25-30 kg) were used. AFG were collected from the bucal fat pad, and grafted in the intramuscular pocket (biceps femoralis muscle). IP model was based on a fusiform ressection followed by primary closure "under tension". A blood pressure catheter located in the intramuscular region connected to a pressure module was applied to quantify IP. Results: The mean operative time was 236 min (210 - 272 min). All the AFG and muscular segments were removed successfully. Average interstitial pressure CP and H were 3 and 10.6 mmHg respectively. The AFG were biopsied for histopathological analysis 30 days after graft. Hematoxylin-eosin staining and immunohistochemical analyzes (TNF-alpha, CD31 and Perilipine with monoclonal antibodies) were employed. Conclusion: The data show that minipigs model could be used as a recipient site for autologous fat graft techniques and allow the development of studies to explore the AFG intake and pathophysiology response.