Lipid peroxidation in human spermatozoa as relatd to midpiece abnormalities and motility

The formation of malondialdehyde (MDA), a product of lipid peroxidation (LPO), was measured in human spermatozoa from 27 subjects with normal sperm characteristics. Peroxidation of lipids in washed spermatozoa was induced by catalytic amounts of ferrous ions and ascorbate and malondiaidehyde dctermint-d by thiobarbituric method. MDA formation varied considerably from one sample to another. The studied population showed a strong correlation between lipid peroxidation potential (amount of MDA formed by 10⁸ spermatozoa after 1 hour of incubation) and 1) initial motility r = ?0.623, P = 0.001; and 2) morphologic abnormalities of the midpiece r = 0.405, P = 0.05. These results suggest that poor motility is linked with membrane fragility and that spermatozoa with midpiece abnormalities probably have membrane and/or cytoplasmic antiperoxidant system defects. Because LPO potential is related to the two most important characteristics of fertility, it seems possible that it has the potential to become a good biochemical index of semen quality.     

Spermatogenesis-related change in the synthesis of the creatine kinase B-type and M-type isoforms in human spermatozoa

We have demonstrated earlier that the per sperm creatine-N-phosphotransferase (CK) activity was increased in oligospermic vs. normospermic men. The increased sperm CK activity is related to higher concentrations of cellular CK, which may indicate a defect of cytoplasmic extrusion during spermatogenesis. In the present work, we examined whether in spermatozoa, similar to muscle, there is a change in the synthesis of B-CK and M-CK isoforms during cellular differentiation. In 109 normospermic and 50 oligospermic specimens (sperm concentrations 60.6 +/- 3.7 vs. 8.8 +/- 1.3 million sperm/ml; all values expressed as mean +/- SEM), the relative concentrations of the M-CK isoform (M-CK/M-CK + B-CK) were 27.2% +/- 2.1% vs. 6.7% +/- 0.9% (P less than 0.001). The per sperm CK activities showed comparable differences (0.21 +/- 0.02 vs. 0.89 +/- 0.1 CK IU/100 million sperm; P less than 0.001) in the two groups, and there was a close correlation between per sperm CK activities and M-CK concentrations (R = 0.69, P less than 0.001, N = 159). This indicates that the loss of cytoplasm and the commencement of M-CK isoform synthesis are related events during the last phase of spermatogenesis, also that the incidence of spermatozoa with incomplete cellular maturation is higher in oligospermic specimens. In characterizing the M-CK, we found that sperm (unlike muscle tissue) lack the MB hybrid of CK dimers. However, in the presence of muscle M-CK, the muscle-sperm MB-CK hybrid has formed. Thus in sperm and muscle the M-CK isoforms are structurally different, whereas the B-CKs are apparently homologous.(ABSTRACT TRUNCATED AT 250 WORDS)     

Role of glutathione peroxidase in protecting mammalian spermatozoa from loss of motility caused by spontaneous lipid peroxidation

Mouse and human spermatozoa, but not rabbit spermatozoa, have long been known to be sensitive to loss of motility induced by exogenous H₂O₂. Recent work has shown that loss of sperm motility in these species correlates with the extent of spontaneous lipid peroxidation. In this study, the effect of H₂O₂ on this reaction in sperm of the three species was investi gated. The rate of spontaneous lipid peroxidation in mouse and human sperm is markedly enhanced in the presence of 1-5 mM H₂O₂, while the rate in rabbit sperm is unaffected by H₂O₂. The enhancement of lipid peroxidation, the rate of reaction of H₂O₂ with the cells, the activity of sperm glutathione peroxidase, and the endogenous glutathione content are highest in mouse sperm, intermediate in human sperm, and very low in rabbit sperm. Inac tivation of glutathione peroxidase occurs in the presence of H₂O₂ due to complete conver sion of endogenous glutathione to GSSG: No GSH is available as electron donor substrate to the peroxidase. Inactivation of glutathione peroxidase by the inhibitor mercaptosucci nate has the same effect on rate of lipid peroxidation and loss of motility in mouse and human sperm as does H₂O₂. This implies that H₂O₂ by itself at 1-5 mM is not intrinsically toxic to the cells. With merceptosuccinate, the endogenous glutathione is present as GSH in mouse and human sperm, indicating that the redox state of intracellular glutathione by itself plays little role in protecting the cell against spontaneous lipid peroxidation. Mouse and human sperm also have high rates of superoxide production. We conclude that the key intermediate in spontaneous lipid peroxidation is lipid hydroperoxide generated by a chain reaction initiated by and utilizing superoxide. Removal of this hydroperoxide by gluta thione peroxidase protects these sperm against peroxidation; inactivation of the peroxidase allows lipid hydroperoxide to increase and so increases the peroxidation rate. Rabbit sperm have low rates of superoxide reaction due to high activity of their superoxide dismutase; lack of endogenous glutathione and low peroxidase activity does not affect their rate or lipid peroxidation. As a result, these sperm are not affected by either H₂O₂ or mercapto-succinate. These results lead us to postulate a mechanism for spontaneous lipid peroxida tion in mammalian sperm which involves reaction of lipid hydroperoxide and O₂ as the rate-determining step.     

The effects of pilates exercise on lipid metabolism and inflammatory cytokines mRNA expression in female undergraduates

[Purpose]

The purpose of the study was to verify the effects of Pilates exercise by observing the impact of 8 weeks of Pilates exercise on lipid metabolism and inflammatory cytokine mRNA expression in female undergraduates in their 20s who had no prior experience in Pilates exercise and had not exercised in the previous 6 months.

[Methods]

There were 18 subjects with no prior experience in Pilates exercise. The subjects were separated into the Pilates exercise group (n = 9) and the non-exercise control group (n = 9). The former performed Pilates exercise for 60-70 minutes over 8 weeks with a gradual strength increase of 9-16 in the Rating of Perceived Exercise (RPE). The body composition, creatine kinase in the bloodstream and lipid metabolism (TC, LDL-C, HDL-C, TG) were measured before and after the experiment and Real-Time PCR was used to investigate the mRNA expression of the inflammatory cytokines IL-6 and TNF-⍺.

[Results]

The creatine kinase (CK) in the blood had significant differences between the groups. The test group showed significant increase compared to the control group after 8 weeks of Pilates exercise (p = 0.007). Lipid analysis showed that the level of high-density lipoprotein cholesterol (HDL-C) was significantly different in the two groups (p = 0.049), with the Pilates exercise group exhibiting significantly higher levels compared to the control group. No significant differences were observed in the levels of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and triglyceride (TG). IL-6 mRNA expression did not show significant differences between the groups either. Timing and TNF-α mRNA expression showed significant effect in both the exercise and the control groups (p = 0.013) but no correlation.

[Conclusion]

It was found from the study that Pilates exercise for 8 weeks affected CK expression (the muscle damage marker) and induced positive changes in the levels of high-density lipoprotein.     

Possible Role of Nitric Oxide on Fertile and Asthenozoospermic Infertile Human Sperm Functions

The capacity of human sperm fertilization is principally dependent on sperm motility and membrane integrity. Oxygen-derived free radicals, such as superoxide anion, are known to impair sperm motility and membrane integrity by inducing membrane lipid peroxidation (LPO). Nitric oxide (NO), a biologically active free radical, has recently been shown to inactivate superoxide and increase intracellular guanosine-3', 5'-cyclic monophosphate (cGMP). The aim of this study is to investigate the effects of NO on human sperm motility, viability, lipid peroxidation and cGMP in fertile and asthenozoospermic infertile individuals in vitro. Semen samples were obtained from 10 fertile volunteers and 10 asthenozoospermic infertile patients. Washed spermatozoa were incubated at 37°C in Ham's F-10 medium with 0, 25, 50, 100, 200, or 400nM sodium nitroprusside (SNP, Na₂ [Fe(CN) ₅NO] · 2H₂O), a nitric oxide releaser. Samples were analyzed for viability, determined by eosin-Y dye exclusion method at 0, 1, 2, 3, 5 and 6 h of incubation; motility, determined by the trans-membrane migration method within 2 h of incubation; LPO determined by malondi-aldehyde (MDA) -thiobarbituric acid method at 3 h of incubation; and the intracellular cGMP, determined by ¹²⁵I-cGMP radioimmunoassay at 3 h of incubation. The results showed: in both fertile and infertile samples, viability, trans-membrane migration ratio and the levels of intracellular cGMP in 25-100nM SNP-treated spermatozoa were significantly higher than those in control groups, while MDA contents in treated groups were significantly lower than those in controls. However, when concentrations of SNP increased to 200-400nM, the opposite effects were exhibited. The effects of SNP on these processes were biphasic within 25-400nM. The most effective concentration was 100nM. These data suggested that NO is beneficial to sperm viability and motility in both fertile and infertile individuals, and that reduction of lipid peroxidative damage to sperm membranes and increase of intracellular cGMP may be involved in these benefits.     

Creatine phosphokinase in domestic cat epididymal spermatozoa

Mammalian spermatozoa that have not completed final testicular sperm maturation have residual cytoplasm and increased creatine phosphokinase (CK) content. This study determined: (1) if CK could be detected by immunostaining cat spermatozoa from the caput, corpus, and cauda epididymis, (2) fluctuations in the proportions of spermatozoa with mature or immature CK-staining patterns during epididymal sperm transit, and (3) how well sperm maturity (as determined by a CK marker) correlated with testicular or epididymal dysfunctions associated with morphological sperm abnormalities. One epididymis was collected from each of 37 cats after orchiectomy and processed immediately to allow sperm morphology evaluations on a 'regional' basis. Sperm released from the contralateral epididymis were evaluated for motility, sperm membrane integrity, and immunostaining with CK-B antibodies. Proportions of spermatozoa with malformed or detached heads, proximal droplets and acrosomal or midpiece abnormalities decreased (P < 0.05) from the caput to the cauda epididymis. In contrast, proportions of spermatozoa that were motile, membrane-intact or with flagellar abnormalities or distal droplets increased (P < 0.05) from the caput to cauda region. Percentages of spermatozoa with an immature CK-staining pattern also decreased (P < 0.05) with epididymal transit (which differs from that reported for the human and stallion). There was no correlation (P > 0.05) between sperm morphology and the CK-staining patterns. In summary, the results reveal that some specific sperm malformations in the domestic cat are of testicular origin, whereas others develop during epididymal transit.     

不同人群精液质量现状的分析

通过对 434例有生育力、346例生育力不明男性的精液质量进行检测 ,并与同实验室 80年代前期 1 1 0例的数据相比较 ,评价目前男性精子质量的现状。结果表明 ,精子质量均明显降低 ,以精子数目中的计数和总数的降低最为明显 ,分别降低 5 4 .2 %～ 98.9%和 39.7%～ 1 1 4.5 % ;出现异常指标的异常百分率以精子活动性中的活动率、a级活力、a +b级活力最高 ,分别达到 1 8.4%～ 42 .3%、37.5 %～ 68.1 %、39.5 %～ 75 .2 % ;各指标在正常值范围内的比率仅占 33.6%和 2 6.0 %。因此 ,提出精液质量的普遍降低应引起足够重视。