A Modified Silver Methenamine Masson Trichrome Stain Using Methyl Green for Staining of Renal Biopsies
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Journal of Histotechnology ISSN: 0147-8885 (Print) 2046-0236 (Online) Journal homepage: http://www.tandfonline.com/loi/yhis20 A modified silver methenamine Masson trichrome stain using methyl green for staining of renal biopsies Alex Laslowski To cite this article: Alex Laslowski (2016): A modified silver methenamine Masson trichrome stain using methyl green for staining of renal biopsies, Journal of Histotechnology, DOI: 10.1179/2046023615Y.0000000012 To link to this article: http://dx.doi.org/10.1179/2046023615Y.0000000012 Published online: 16 Mar 2016. Submit your article to this journal View related articles View Crossmark data Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=yhis20 Download by: [University of California, San Diego] Date: 27 March 2016, At: 19:44 Technical Note A modified silver methenamine Masson trichrome stain using methyl green for staining of renal biopsies Alex Laslowski Monash Medical Centre Clayton, Medical Scientist, Anatomical Pathology, VIC, Australia Renal pathology uses a battery of stains to allow proper assessment of all renal components. One of the most useful of these stains is the silver methenamine with a Masson Trichrome counterstain (SMMT). The SMMT stain uses thin 1-um sections to identify immune complexes deposits on the basement membranes and in the mesangium of the glomerulus and can be an excellent and inexpensive method. Problems can, however, occur when the stain is not performed by a technician or the stain needs to be performed in large numbers. A variation to the SMMT method has proved to provide a better, more robust and reproducible counterstain. The new method substitutes Light Green SF, from the traditional Masson Trichrome stain, for a much smaller dye molecule size Methyl Green allowing for better penetration and a stronger bonding to the tissue components. Keywords: Light green SF, Masson trichrome, Methyl green, Silver methenamine Introduction It was decided to find an alternative stain, which The pathology department at Monash Medical would provide more consistent and reliable results, Centre (Melbourne, VIC, Australia) has routinely but still provide a similar histological image for diag- used the SMMT stain1 for all manual staining of nostic purposes. The commonly accepted theory for renal biopsies since the early 1990s. The SMMT the Masson Trichrome stain of dye molecular size stain provides excellent information for the pathol- was applied to finding a suitable stain, but it was ogist including information on the glomerular base- the obverse which proved to be correct in our inves- ment membrane (GBM) such as thickening, tigations. We tested numerous modifications to the duplication, and membranous spikes all of which Masson Trichrome using the traditional dyes of are demonstrated by the silver component of the Light Green SF and Aniline Blue with varying con- SMMT stain. The addition of a Masson Trichrome centrations and solvents with little success. The counterstain provides additional information such issue was that the Light Green SF did not have the as the presence of protein deposits on basement same affinity for the tissue structures after the section membranes and the presence of fibrin. The current had been stained with silver methenamine solution. Downloaded by [University of California, San Diego] at 19:44 27 March 2016 issue when performing a SMMT stain it is very diffi- The Light Green SF would simply wash out of the cult to control the staining intensity of the Light section in water and/or alcohols leading to problems Green SF in the various tissue components. This is with dehydration resulting in uneven staining, com- due to a major problem is the stain retention of the plete loss of stain, or over staining of the tissue sec- dye Light Green SF in the tissue sections. Experience tions due to rapid dehydration techniques. with the stain in our laboratory has shown that the stain needs to be performed by a skilled technician Staining with silver methenamine Masson to achieve a satisfactory result. trichrome Methenamine silver is commonly used in renal pathology to demonstrate the fine detail of glomerularopathies, this has been common place since Jones2 first described the Correspondence to: Alex Laslowski, Monash Medical Centre Clayton, advantages of such a technique. The method utilizes per- Medical Scientist, Anatomical Pathology, 246 Clayton Road, Clayton, VIC 3168, Australia. Email: [email protected] iodic acid to oxidize the basement membranes, which is ß National Society for Histotechnology 2015 DOI 10.1179/2046023615Y.0000000012 Journal of Histotechnology 2015 VOL.00 NO.0 1 Laslowski Staining of renal biopsies then subjected to a warm methenamine silver solution, Light Green SF would readily be removed during dehy- which produces a silver deposition on the carbohydrates dration and clearing of the stained sections. This is a on collagen type IV fibers, which make up basement common problem, which is also experienced in other membranes of the GBM. The methenamine silver stain laboratories so to compensate the tissue sections need has since undertaken a number of variations in terms to be rapidly dehydrated with only 2–3 dips in absolute of the counterstain used. Jones2 originally suggested alcohol.1 Due to the loss of the Light Green SF, the stain the use of a Hematoxylin and Eosin counterstain, over needed to be performed by a skilled and adequately the years an alternative counterstain of Light Green trained laboratory staff member. Even in the hands of SF (CI 42095) has been used in preference by many a skilled operator variations in staining could range institutions. The pathological information which the from the minor to extreme; the main problems included Methenamine silver stain is intended to provide either complete loss of the Light Green SF, sections is demonstrated membranous duplication, spikes, or completely over stained with no differentiation for thickening, in addition to vacuolization of the GBM tissue structures with the Light Green SF, whilst the when deposits are present. Early in the 1990s, in Mel- variations in between were deemed satisfactory for diag- bourne, Australia, a method1 was developed, which nostic evaluation. The practice of rehydrating and used a Masson Trichrome counterstain, this was con- trying corrective action to improve the staining qualities sidered by many to be an improvement to a Hematoxylin were often not very successful. The reason for the loss of and Eosin (H&E) or Light Green SF counterstain in that the Light Green component is unknown, but is most it was able to demonstrate both fibrin and highlight the likely due to the binding sites of the proteins usually presence of glomerular protein deposits. The ability to stained with Light Green SF are masked or altered demonstrate these additional features provided infor- during the silver impregnation stage hindering the abil- mation in a paraffin section, which would otherwise ity of the Light Green SF to adequately bind. have required a more detailed examination by electron 3 microscopy. The stain was not intended to replace Investigations to correct the silver methenamine electron microscopy but to increase the sensitivity by Masson trichrome light microscope examination. Multiple variables of the Light Green SF were tested Connective tissue stains including altering the concentration, pH, and stain- ing times. These did not produce similar staining The term ‘‘Trichrome’’ is used for a number of tech- characteristics as are traditionally seen in a MT niques, which selectively demonstrate muscle, col- stain. Renal sections were seen to be either comple- lagen fibers, fibrin, and erythrocytes. The staining tely over stained or had no Light Green SF in the mechanism of the MT stain is not entirely known, section. Dehydrating through alternative solutions but the staining theory is thought to be related to such as acetone, isopropynol, or air drying, which tissue permeability and molecular size of the dye were aimed at retaining the Light Green SF in the molecules.4 As tissue undergoes fixation tissue struc- tissue sections proved to be unsatisfactory or repro- tures such as muscle and collagen are affected differ- ducible. Alternate Trichrome stains were also investi- ently resulting in altered permeability; the gated such as Van Gieson, Martius Scrarlet Blue, and permeability of the tissue structures are then Gomori (Aldehyde Fuchsin Gomori), but all failed to exploited during the Masson Trichrome (MT) stain- stain the renal tissue adequately or demonstrate the Downloaded by [University of California, San Diego] at 19:44 27 March 2016 ing process. The basis of the theory is that stains same tissue components as seen in the MT. are applied to the tissue according to molecular Aniline Blue was considered as an alternative weight from the smallest dye molecule Biebrich Scar- counterstain to the Light Green SF; Aniline blue is let (Mwt 556)5 and finishing with the larger dye mol- quite often substituted for Light Green SF when per- ecule Light Green SF (Mwt 815),6 and that the larger forming a Masson Trichrome stain. Staining with dye will displace the smaller dye molecules in tissue Aniline Blue proved to be more consistent with components which are large enough for that particu- regards to stain retention and staining of relevant cel- lar molecule to penetrate. The addition of Biebrich lular components, but due to the intensity of the blue Scarlet to Acid Fuchsin in the MT stain helps to stain pathologists viewing the slides felt that infor- differentiate between cytoplasm/muscle and RBC’s. mation was obscured and hard to interpret. Problems with performing the silver A closer look at Aniline blue as a dye to see why methenamine Masson trichrome this was being retained by the tissue structures and The problems, which were experienced in our labora- whether there might be a similar dye with a green tory when performing the SMMT stain was that the chromophobe revealed a clue.