Dear M. M.S Gaballa,

I am sure there will be help really fast by some expert....(unfortunately my daily time for RG has been usedup now....) BUT:

you might find really fast a solution or even recipes (searching in RG-QUESTIONS for picrosirius) which results in inserting / linking to:  https://www.researchgate.net/search.Search.html?type=question&query=picrosirius

Best wishes and good luck, WM

Indeed, it can be assumed that the primary requester, M.M.S. Gaballa has lost interest in his question.... and: To be honest: from a short search by means of any available search machine or in PubMed or Scholar Google (see below) - as well as the reference underlying the pubmed-article as given by Monyer Al-Fatlawi - available ONLY as abstract (the original paper accessible only as PPV=pay-per-view) one would have insight into the special staining (of / for collagen, polarizing microscopy). 

For convenience only:     https://www.ncbi.nlm.nih.gov/pubmed/2438817 =

>>  Dolber PC, Spach MS.: Picrosirius red staining of cardiac muscle following phosphomolybdic acid treatment.    Stain Technol. *) 1987 Jan;62(1):23-6.

*) NB:   Stain Technology has a changed Journal Title:  "Biotechnic and Histochemistry"  published by Taylor & Francis Group  / INFORMA (cf: http://www.tandfonline.com/action/doSearch?target=titleSearch&SeriesKey=ibih20 ) 

Abstract: When the picrosirius red technique was applied to cardiac muscle sections, intense yellow myocyte staining sometimes obscured thin collagenous septa. The picrosirius red technique was modified to include treatment of the sections in 0.2% (w/v) aqueous phosphomolybdic acid prior to staining. With 1-5 min treatment, cytoplasmic staining was eradicated; diminution of collagen staining occurred only with long treatments at much higher concentrations of phosphomolybdic acid. Using this phosphomolybdic acid-picrosirius red technique, collagenous septa as thin as 0.2-0.5 micron and fine collagen fibers making up the septa were clearly discernible. The technique also worked well on sections stained by other techniques and then destained. The phosphomolybdic acid-picrosirius red technique should be useful in experiments designed to investigate the effects of collagen distribution on the electrical and mechanical behavior of cardiac muscle.

PMID:   2438817   [Indexed for MEDLINE]  

Thanks for explaining the addition of phosphomolybdic acid. I was following a manufacturer's instruction to stain frozen sections, where the phosphomolybdic acid treatment was not required. But I ended up with a strong staining of cytoplasma.

Dear Dr. Jun Zhao, if it was my answer which helped you to get rid of cytoplasmic staining: you're welcome and thanks to Dolber PC, Spach MS.,1987 who found it worthwhile to write a scientific/technical article...Regards, W.M.