HISTOCHEMICAL EVALUATION of NUCLEIC ACIDS PRESERVATION USING DIFFERENT TYPES of FIXATIVES

Abstract

This is an expermental study to assess the preservation of nucleic acids in three types of tissues by the use of five different fixatives. The study was conducted in Elobied during the period from April 2010 to august 2010. Blocks were obtained from rabbit tissue, Formal saline, Buffer Formalin, Carnoy’s, Methacarn and Elseriow's fixatives were used. Intestinal. Tongue and liver tissues were taken from a rabbit. Three temperatures of fixation were selected 37°C, 25°C and 4°C. After application Feulgen and Methyl Green Pyronin for nucleic acids quantification, Carnoy’s fixative gave high nucleic acids preservation and so was Methacarn fixative. Elseriow's fixative, which was used for the first time in this study gave excellant nucleic acids preservation; whereas, Formal saline and Buffer formalin were gave acceptable results in nucleic acids preservation. When tissues fixed at 37°C the amount of preserved nucleic acids was more than these detected at other temperatures, although, results obtained at 25°C was good. Formalin containing fixatives i.e. formal saline and buffer formalin gave good results at 4°C. ‫‪Although, the nucleic acid of all tissue was best preserved, the intestinal‬‬ ‫.‪tissue gave better result followed by liver and lastly the tongue‬‬