Picrosirius-polarization staining method as an efficient histopathological tool for collagenolysis detection in vesical prolapse lesions Luciano Figueiredo Borges a , Paulo Sampaio Gutierrez a , Heitor Ricardo Cosiski Marana b , Sebastia ˜o Roberto Taboga c, * a Heart Institute (Incor), University of Sa ˜o Paulo School of Medicine, Sa ˜o Paulo, Brazil b Department of Gynecology and Obstetrics, Faculty of Medicine of Ribeira ˜o Preto, University of Sa ˜o Paulo, Sa ˜o Paulo, Brazil c Microscopy and Microanalysis Laboratory, Department of Biology, Sa ˜o Paulo State University-UNESP, Institute of Biosciences, Humanities and Exact Sciences-IBILCE, Rua Cristova ˜o Colombo, 2265 Jardim Nazareth, 15054000 Sa ˜o Jose ´ do Rio Preto, Sa ˜o Paulo, Brazil Received 4 September 2006; received in revised form 20 October 2006; accepted 21 October 2006 Abstract The Picrosirius-polarization method has been indicated as a selective histochemical stain for collagen detection in tissue sections. This method can also be of value for studying collagen degradation given that, under polarized light, collagen displays birefringence due to its molecular order. The aim of this study is to highlight this staining method as an additional instrument for a rapid and excellent confirmatory diagnosis of the presence of collagenolysis in connective tissue in the vaginal wall with vesical prolapse lesion, in tissue sections. Dramatic changes in collagen morphology were found in vaginal mucosa in vesical prolapse disorder: they were weakly stained by Sirius red and under polarized light appeared as thin, pale (weakly birefringent), greenish, and with fibers more scattered, while the histoarchitecture of the organ showed a disrupted appearance. Thus, in the present study, we showed in vaginal mucosa in the vesicle prolapse that corroded collagenous framework appears as fragmentary and irregularly separated collagenous structures, that are weakly birefringent, corresponding to a molecular disorganization of these fibers caused by collagenolysis. # 2006 Elsevier Ltd. All rights reserved. Keywords: Collagen; Extracellular matrix; Vesical prolapse; Sirius red; Collagenolysis 1. Introduction The main constituent of connective tissue is collagen. The quality and organization of collagen fibers significantly affect the tensile strength of the connective tissue and consequently the support that is provided to the organs (Junqueira and Montes, 1983; Montes, 1996; Aumailley and Gayraud, 1998). The Picrosirius-polarization method is a selective histochem- ical procedure for collagen detection in paraffin-embedded tissue sections. Interstitial collagens exhibit different interference colors and intensities of birefringence in tissue sections analyzed with the aid of this method, which is thus also useful for studying the differential distribution of the structurally distinct collagen types in routinely fixed, paraffin-embedded organs (Montes, 1996; Andrade et al., 1997; Junqueira et al., 1978, 1980). Recently we showed the application of Picrosirius associated with fluorescence in detecting collagen and elastin when these two structures are present simultaneously (Borges et al., 2005). Additionally, the Picrosirius polarization method can also be of value for the study of collagen degradation (Junqueira et al., 1980; Borges et al., 2005; Luque and Montes, 1989; Luque et al., 1997; Perez-Tamayo and Montfort, 1980) provided that under polarized light the collagen displays birefringence due to its molecular arrangement. Thus, under pathological conditions in which collagen degradation and therefore molecular disorder occur, this birefringence will show a different pattern in comparison with that presented by the collagen molecules in a normal tissue. Collagen degradation depends on the activity of the matrix metalloproteinases (MMPs), a family of structurally related proteins produced by connective and inflammatory cells that www.elsevier.com/locate/micron Micron 38 (2007) 580–583 * Corresponding author. Tel.: +55 17 32212386; fax: +55 17 32212390. E-mail address: taboga@ibilce.unesp.br (S.R. Taboga). 0968-4328/$ – see front matter # 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.micron.2006.10.005