Not using phosphomolybdic acid in masson’s trichrome: a safer alternative protocol for improving collagen staining?

Martins, Érica B.; Antunes, Beatriz; Santos, Carolina P.; Palma, João; Borges-Ferro, Amadeu

http://hdl.handle.net/10400.21/17251

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Abstract(s)

Histochemical techniques are relevant for laboratory diagnosis, leading to a growing need to optimize protocols. To highlight collagen in blue, Masson's Trichrome (MT) uses acid fuchsin, phosphomolybdic acid (PmA), and aniline blue. The principle used in this technique is based on the difference in permeability of the three-dimensional network of the precipitated cationic proteins and the size of the anionic compounds, known as the "permeability and diffusion theory", the staining being dependent on fixation and molecular size of the dyes. The phosphomolybdic acid (PmA) function is not clear and this chemical is harmful, corrosive, and toxic to the environment. In this experimental study, we intended to compare the quality of MT staining, with and without using PmA, using different fixation times of tissues. Five swine organs (liver, kidney, tongue, lung, and heart) were submitted to 12h, 24h, 48h, and 96h fixation, histologically processed, sectioned, and stained by MT, with and without PmA. Stained tissues were assessed by two experts using a data collection tool that generated a score on a 0-100 scale. According to the data obtained, 48h was the fixation time with the best results for MT staining quality. The results showed that, when individually analyzed, the quality of collagen staining without PmA was significantly higher (t120,713=-6,261, p<0,001). The overall Final Score for TM showed differences between the method with and without PmA (t158=-3,287, p<0,001), with final mean scores of 84.11±8.23 and 88.48±8.60, respectively. In conclusion, the protocol without PmA demonstrated a better overall quality of MT staining.

Keywords

Masson's trichrome staining Phosphomolybdic acid Fixation Collagen

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http://hdl.handle.net/10400.21/17251

Citation

Martins EB, Antunes B, Santos CP, Palma J, Borges-Ferro A. Not using phosphomolybdic acid in masson’s trichrome: a safer alternative protocol for improving collagen staining? Trends Biomed Lab Sci. 2023;1(1):29-36.