Lipid changes of goat sperm plasma membrane during epididymal maturation
TL;DR: The altered lipid profile of the mature sperm membrane leads to changes in its fluidity that play an important role in determining the structure and functions of the biomembrane.
About: This article is published in Biochimica et Biophysica Acta.The article was published on 1991-01-30. It has received 76 citations till now. The article focuses on the topics: Sperm plasma membrane & Membrane lipids.
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TL;DR: There is cell‐to‐cell variability in the concentration of DHA in human sperm and that there is a net decrease in DHA content in sperm during the process of sperm maturation are indicated.
Abstract: The oxidation of phospholipid-bound docosahexaenoic acid (DHA) has been shown to be one of the major factors that limit the motile life span of sperm in vitro. Sperm samples show high cell-to-cell variability in life span and, consequently, in susceptibility toward lipid peroxidation. Therefore, we postulated that there is also cell-to-cell variability in DHA concentration in human spermatozoa. In this study, the concentration of DHA in subsets of human spermatozoa isolated by a discontinuous Percoll density gradient was determined by gas chromatography. Four subsets of human spermatozoa were isolated using a discontinuous Percoll gradient: fraction 1 was enriched in immature germ cells and immature sperm, fractions 2 and 3 contained, mostly, immature sperm with cytoplasmic droplets, and fraction 4 contained, for the most part, morphologically normal sperm, as determined by histochemical analysis. The results indicated that there were significant differences in DHA content in sperm from all 4 fractions. DHA content in sperm from fraction 1 was 2.5-fold higher than that found in fraction 4. DHA content in mouse sperm obtained from the seminiferous tubules was 3-fold higher than that found in mouse sperm obtained from the epididymis, consistent with the findings observed in ejaculated human sperm. The results of this study indicate (i) there is cell-to-cell variability in the concentration of DHA in human sperm and (ii) that there is a net decrease in DHA content in sperm during the process of sperm maturation.
94 citations
TL;DR: The phospholipid and fatty acid composition of sperm was studied in 8 healthy and 16 infertile men and there was significant positive correlation between docosahexaenoic acid and sperm motility and negative correlation between linolenic Acid and spermatozoa motility.
Abstract: The phospholipid and fatty acid composition of sperm was studied in 8 healthy and 16 infertile men. Infertile men randomly formed from the patients with normal semen parameters according to WHO criterion. Therefore, all semen parameters of infertile patients were similar to the same characteristics of the semen of healthy men, except the abnormal forms. The amount of abnormal forms in infertile men was significantly higher than in healthy men. Sperm from infertile men show a drastic loss of phosphatidyl ethanolamine. At the same time, the significant increase of phosphatidyl serine in the sperm and seminal plasma of sterile patients was found. Lysophosphatidyl serine in the sperm of the infertile men was detected. Fatty acid composition of the semen of infertile men was altered. The levels of stearic and n-3 polyunsaturated fatty acids (eicosopentaenoic and docosahexaenoic acids) was dramatically lowered, but the values of some n-6 polyunsaturated fatty acids (linolenic and docosatetraenoic) acids increased. There was significant positive correlation between docosahexaenoic acid and sperm motility (r = .82, p < .001) and negative correlation between linolenic acid and spermatozoa motility (r = -0.58. p < .05). Infertility of men with normal semen quality can originate from the disorder of sperm lipid metabolism. The drastic loss of phosphatidyl ethanolamine and n-3 polyunsaturated fatty acids with simultaneous enhancement of phosphatidyl serine and some n-6 polyunsaturated fatty acids in sperm could be an important cause of male infertility.
93 citations
TL;DR: The results of this study suggest that intake of trans fatty acids may be related to lower semen quality, and provide further evidence that diet is a modifiable factor that could impact male fertility.
Abstract: Study question Is intake of fatty acids related to semen quality among young men? Summary answer The intake of trans fatty acids is inversely related to total sperm count in healthy young men. What is known already Spain has seen an increase in the proportion of calories consumed as fat over the same period that a downward trend in semen quality has been observed. In addition, rodent models suggest that trans fat intake may severely affect testicular function. Study design, size, duration Cross-sectional study of 209 men recruited between October 2010 and November 2011. Participants/materials, setting, methods A group of 209 healthy young university students 18-23 years of age provided a semen sample and completed a previously validated food frequency questionnaire. The association between intake of fatty acids with semen quality parameters (sperm concentration, motility, morphology and total count) was assessed using multivariate linear regression. Main results and the role of the chance Trans fatty acid intake was inversely related to total sperm count after adjusting for potential confounders (P, trend = 0.03). The multivariate adjusted mean (95% confidence interval) total sperm count in increasing quartiles of trans fat intake was 144 (110-190), 113 (87-148), 100 (18-130) and 89 (69-117). There also was an inverse association between cholesterol intake and ejaculate volume (P, trend = 0.04). No other statistically significant relations were observed. Limitations, reasons for caution The cross-sectional design of the study limits causal inference, we cannot exclude the possibility of unmeasured confounding and there was insufficient statistical power to identify modest associations. Wider implications of the findings The results of this study, together with previous experimental work in rodents and biomarker studies among infertility patients, suggest that intake of trans fatty acids may be related to lower semen quality. Although the data provide further evidence that diet is a modifiable factor that could impact male fertility, it is not known whether the observed differences in sperm count translate into differences in fertility. Study funding/competing interest(s) This work was supported by The Seneca Foundation, Regional Agency of Science and Technology, grant no 00694/PI/04, Ministerio de Ciencia e Innovacion, Instituto de Salud Carlos III (FIS), grant no PI10/00985, and grant P30 DK46200 from the National Institutes of Health. The authors have no competing interests to declare.
91 citations
Cites background from "Lipid changes of goat sperm plasma ..."
...In multiple species, including humans, sperm membranes increase the relative amount of PUFAs, particularly of docosahexaenoic acid, during epididymal maturation (Hall et al., 1991; Rana et al., 1991; Haidl and Opper, 1997; Lenzi et al., 2000; Ollero et al., 2000)....
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TL;DR: The catalysis of oleic acid formation from residual milk triglycerides by BUSgp60 appears responsible for the deterioration of goat spermatozoa when unwashed semen is diluted in skimmed milk-based extenders.
Abstract: The aim of the present study was to elucidate the mode of action of goat bulbourethral lipase (BUSgp60 lipase) previously identified as responsible for the deterioration of goat sperm viability in skimmed milk-based extenders. Milk fractions were purified by micro- and ultrafiltration and characterized by SDS-PAGE, thin layer chromatography, triglyceride quantitative analysis and by their ability to potentiate the lipase and the sperm-deteriorating activity of the bulbourethral lipase. Components in both the phosphocaseinate and soluble whey protein fractions enhanced the lipase activity of BUSgp60 but only the phosphocaseinate fraction, which contains triglycerides, promoted deterioration of spermatozoa in the presence of bulbourethral gland secretion. These data suggest that the sperm-deteriorating effect of bulbourethral gland secretion is due to the catalysis of triglyceride hydrolysis, and that proteins increase this activity. BUSgp60 hydrolysed milk triglycerides and triolein very effectively, and its lipase activity was enhanced by several highly purified milk proteins. The major cis-unsaturated fatty acid from milk (oleic acid) but not the major saturated fatty acid (palmitic acid) exhibited dose-dependent detrimental effects on goat spermatozoa. Therefore, the catalysis of oleic acid formation from residual milk triglycerides by BUSgp60 appears responsible for the deterioration of goat spermatozoa when unwashed semen is diluted in skimmed milk-based extenders. The precise mechanism of action of oleic acid remains to be elucidated but the drawbacks of washing buck semen might be avoided by inhibiting BUSgp60 or by depriving it of substrate.
85 citations
TL;DR: It is concluded that trout spermatozoa do not display any homeoviscous adaptations in these conditions and the dietary fatty acid intake greatly modified the fatty acid profile of plasma membrane phospholipids.
Abstract: The effect of a long-term adaptation of rainbow trout to 8 and 18°C combined with a corn oil-or a fish oil-supplemented diet on the characteristics of the spermatozoan plasma membrane was investigated. The experiment lasted up to 22 mon during which spermatozoa were collected from the mature males. Spermatozoan plasma membranes were isolated by nitrogen cavitation, and the cholesterol content, phospholipid composition and fatty acid pattern were investigated. Membrane viscosity was assessed on whole cells by electron spin resonance using spin-labeled phospholipids. Neither diet nor rearing temperature influenced the cholesterol content of the plasma membrane nor the phospholipid class distribution. The rearing temperature of the broodstock only slightly affected the phospholipid fatty acids. A minor decrease in 18∶0 and increase in monounsaturated fatty acids was observed for the cold-adapted fish. These modifications were not sufficient to affect membrane fluidity, and we conclude that trout spermatozoa do not display any homeoviscous adaptations in these conditions. On the contrary, the dietary fatty acid intake greatly modified the fatty acid profile of plasma membrane phospholipids. The fish oil-fed trout displayed a much higher n−3/n−6 fatty acid ratio than did the corn oil-fed ones, but the 22∶6n−3 levels remained unchanged. Modifications in plasma membrane composition by the diet were obtained although neither of the two diets was deficient in essential fatty acids. The enrichment in n−3 fatty acids, however, did not affect plasma membrane fluidity which was unchanged by the diets.
79 citations
References
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