The effect of the alternatıve solutıons whıch are produced to be used ın place of formalın and xylene on tıssue processıng

Aim: Formaldehyde and xylene are main solutions of tissue processing. But these chemical substances have important toxic, allergen and carcinogenic effects on human body. Nowadays, nontoxic or lesser toxic new commercial solutions have been produced to be used in place of formaldehyde and xylene. It is expected to be compatible with histochemical and immunohistochemical stainings, also with in situ hibridisation and polymerase chain reaction from these new alternative solutions. In this study, we aimed to assess the impact of new alternative solutions on methods mentioned above.Methods: Thirteen different tissue processings were designed and performed on 13 different tissues by using five different fixatives (Formaldehyde, Glyo-Fixx ? , FineFIX ? , Cell block ? ve Greenfix ? ) and four different clearing agents (Xylene, Sub-X ? , Bio Clear ? , Shandon Xylene Substitute ? ). Haematoxylin&Eosine stained sections were compaired by using qualitative histomorfological criterions. Histochemical and immunohistochemical stains were performed by using tissue microarrays. Histochemical staining results were compaired by using qualitative criterions while immunohistochemical staining results were compaired with quantitative datas which were had by using a computer programme (3D Histech NuclearQuant ? , MembraneQuant ? ). Tissue sections were tested for the availability of chromogenic in situ hibridisation, by using a Her-2/neu protocol. Also different tissue processings were compaired at molecular level by performing DNA and RNA extraction, and DNA quality by polymerase chain reaction.Results: The quality of sections was well for all tissue processings. Histochemical staining results showed that all alternative solutions which were used are suitable for this application. Immunohistochemical staining results showed that alternative solutions which contain glyoxal as active agent need optimization fort his application. The clearance of signals with chromogenic in situ hibridisation were nearly same and well for all tissue samples. Furthermore, tissue processes which do not contain formaldehyde were found to be superior compaired with ones which contain formalin as fixative solution on molecular preservation.Conclusion: We have demonstrated that formaldehyde-free fixatives have potential in routine pathology and research to replace formaldehyde in histomorphology and protein preservation. When all parameters were evaluated together it was found that the tissue processes which contain Glyo-Fixx ? , Cell block ? and FineFIX ? as fixative solution were superior compared the others. We have also demonstrated that alternative clearing agents which stayed behind the scenes because of the search of ideal fixative have the potantial in routine pathology to replace xylene.Key Words: Tissue fixation, formalin, DNA, RNA, pathology, molecular