Variation of cholesterol, phospholipid and triacylglycerol content in subsets of human spermatozoa isolated by density gradient

subsets of human spermatozoa isolated by density gradient.Rohollah Setarehbadi 1; Mojgan Atabakhash 1; Amir Fattahi 1; Aboozar Mohagheghi 1; Asad Vaisi-Raygani 2; Hossain Mahjub 3; and Heidar Tavilani Tavilani *, 4 1 Student Research Committee, Hamadan University of Medical Sciences, Hamadan, Iran2 Fertility and Infertility Center, Kermanshah University of Medical Sciences, Kermanshah, Iran3 Department of Epidemiology and Biostatistics, Faculty of Public Health, Hamadan University of Medical Science, Hamadan, Iran4 Urology & Nephrology Research Center, Hamadan University of Medical Sciences, Hamadan Iran*Corresponding author: Heidar Tavilani Tavilani, Urology & Nephrology Research Center, Hamadan University of Medical Sciences, Hamadan Iran, Tel.: +98 8118380717, Fax: +98 8118380313, E-mail: tavilani@gmail.com. Lipid components of spermatozoa have an important role in its functional activity. In this study the concentration of cholesterol, phospholipid, triacylglycerol and total lipid in different subsets of human spermatozoa, isolated as three fractions by a discontinuous PureSperm gradient, was determined. Aliquots of the liquefied semen samples (n=107) were layered on top of the upper layer of 40 and 80% PureSperm gradient. The resulting interfaces 40 and 80% (fraction 1), 80% and pellet (fraction 2), and pellet (fraction 3) aspirated and transferred into separate tubes. Lipids were extracted with 6 volumes of chloroform-methanol (2/1, V/V) and the concentration of cholesterol, phospholipid, triacylglycerol were determined by colorimetric method. Percent of sperm with normal morphology was significantly higher in sperm fraction 3 compared to fraction 2 and 1, while percent of sperm with midpiece and tail defect was significantly higher in fraction 1 compared to fractions 2 and 3 (P<0.01). The amount of cholesterol, phospholipid and total lipid of sperm fractions 2 and 3 were about 1.5-fold higher than that of found in sperm from fraction 1 (P<0.05). This result suggests that the total lipid contents of sperms increase with increasing normal morphology from fraction 1 to 3.