Optimized protocol for immunostaining of experimental GFP-expressing and human hearts.
Morphological and histochemical analysis of the heart is fundamental for the understanding of cardiac physiology and pathology. The accurate detection of different myocardial cell populations, as well as the high-resolution imaging of protein expression and distribution, within the diverse intracellular compartments, is essential for basic research on disease mechanisms and for the translatability of the results to human pathophysiology. While enormous progress has been made on the imaging hardware and methods and on biotechnological tools [e.g., use of green fluorescent protein (GFP), viral-mediated gene transduction] to investigate heart cell structure and function, most of the protocols to prepare heart tissue samples for analysis have remained almost identical for decades. We here provide a detailed description of a novel protocol of heart processing, tailored to the simultaneous detection of tissue morphology, immunofluorescence markers and native emission of fluorescent proteins (i.e., GFP). We compared a variety of procedures of fixation, antigen unmasking and tissue permeabilization, to identify the best combination for preservation of myocardial morphology and native GFP fluorescence, while simultaneously allowing detection of antibody staining toward sarcomeric, membrane, cytosolic and nuclear markers. Furthermore, with minimal variations, we implemented such protocol for the study of human heart samples, including those already fixed and stored with conventional procedures, in tissue archives or bio-banks. In conclusion, a procedure is here presented for the laboratory investigation of the heart, in both rodents and humans, which accrues from the same tissue section information that would normally require the time-consuming and tissue-wasting observation of multiple serial sections.
Department of Biomedical Sciences, University of Padova, Via Ugo Bassi 58/b, 35133, Padua, Italy. tania.zaglia@unipd.it.|Venetian Institute of Molecular Medicine (VIMM), Via Orus 2, 35129, Padua, Italy. tania.zaglia@unipd.it.
Tania
T
Zaglia
Venetian Institute of Molecular Medicine (VIMM), Via Orus 2, 35129, Padua, Italy.|Department of Cardiac, Thoracic and Vascular Sciences, University of Padua, Via A. Gabelli, 61, 35121, Padua, Italy.
Anna
A
Di Bona
Istituto Comprensivo di Carmignano di Brenta, Padua, Italy.
Tatiana
T
Chioato
Department of Cardiac, Thoracic and Vascular Sciences, University of Padua, Via A. Gabelli, 61, 35121, Padua, Italy.
Cristina
C
Basso
Department of Biomedical Sciences, University of Padova, Via Ugo Bassi 58/b, 35133, Padua, Italy.
Simonetta
S
Ausoni
Department of Biomedical Sciences, University of Padova, Via Ugo Bassi 58/b, 35133, Padua, Italy.|Venetian Institute of Molecular Medicine (VIMM), Via Orus 2, 35129, Padua, Italy.|CNR Institute of Neuroscience, Viale G. Colombo 3, 35121, Padua, Italy.
Marco
M
Mongillo
D000818:Animals; D005453:Fluorescence; D049452:Green Fluorescent Proteins / Q000032:analysis* / Q000096:biosynthesis / Q000378:metabolism; D006321:Heart; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008872:Microwaves; D009206:Myocardium / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D055647:Rats, Transgenic
D049452:Green Fluorescent Proteins
Confocal microscopy; Green fluorescent protein; Heart biology; Human myocardium; Immunofluorescence; Stem cells