Polarization microscopy as a tool for quantitative evaluation of collagen using picrosirius red in different stages of CKD in cats

Abstract

Chronic kidney disease (CKD) is a relevant disease in feline clinic. The tubulointerstitial damage, with collagen deposition and fibrosis, is an important result of this process. The aim of this study was to quantify and correlate the deposition of collagen and severity of interstitial fibrosis (IF) in the kidney from cats in different stages of CKD. Kidney fragments from 10 adult cats with CKD were analyzed and stained by Masson's trichrome (MT) and Picrosirius red (PSR) for circular polarized microscopy. Random quantitative analysis was performed on MT sections to classify the degree of IF, per field area, with and without circular polarization. Statistics correlations were performed by Spearman's (ρ; p < .05). There was a significant correlation of IF quantification with the area of interstitial collagen deposition by polarized PSR (PSRp) (r = .7939, p = .0098) and nonpolarized PSR (PSRn) (r = .7781, p = .0080). There was a positive correlation of serum creatinine (sCr) at different stages of CKD with PSRp (r = .7939, p = .0098), PSRn (r = .8667, p = .0027) and MT (r = .7818, p = .0117). Correlations between the percentage of quantified area was also positive from PSRp to PSRn (r = .9030, p = .0009) and PSRp to MT (r = .7939, p = .0098). The PSRN was also correlated with MT (r = .9273, p = .0001). The correlation with IF and sCr follows the disease evolution and the quantification of collagen by PSR is an excellent tool for analyzing the disease severity at different stages.

Potential Radioprotective Effect of AT1 Receptor Antagonists Against Morphological and Ultrastructural Changes in the Testes Induced by Ionizing Radiation

“…Subsequently, the material was processed for embedding in Paraplast plus®. 5 µm sections were stained with Picrosirius-red method (Montes & Junqueira, 1991;Morais et al, 2017) and analyzed under polarized light for qualitative evaluation of collagen.…”

Quantitative and descriptive histological aspects of jaguar (Panthera onca Linnaeus, 1758) ear skin as a step towards formation of biobanks

“…The amount of fibres present in each area was evaluated and recorded using Threshold Color software plug‐in and the 32‐bit red, green and blue (RGB) format conversion. The following parameters were examined: image area (µm 2 ), collagen area (µm 2 ) and percentage of collagen (density) calculated as total area with collagen fibres divided by the total area of the analysed section (Morais et al, ).…”

Picrosirius Red and Masson’s Trichrome Staining Techniques as Tools for Detection of Collagen Fibers in the Skin of Dogs With Endocrine Dermatopathologies

“…The cutaneous collagen deposition per field area was quantitatively analyzed using the modified technique by Morais et al (13) . The tissue sections stained by MT and PSR were morphometrically studied using the NIS-Elements software version 4.2.…”

“…The birefringent regions that corresponded to positive staining (collagen) were converted to white. A threshold was set and the black areas were excluded; the volume of the remaining white area was quantified in relation to the field area captured (13) (Figure 1).…”