Assessing human sperm morphology： top models, underdogs or biometrics？

The assessment of the percentage of spermatozoa having an ＇ideal＇ morphology using so-called strict method is the method recommended in the latest edition of the World Health Organization （WHO） laboratory manual for semen analysis. This recommendation is a result of the statistical association between ＇ideal＇ sperm morphology and fertility, and of the current general belief that sperm morphology assessment should be used primarily as a fertility tool. The notion of an ＇ideal＇ sperm morphology has persisted despite the very low percentage of such spermatozoa in the semen of fertile men, a subject of intense controversy. The detailed categorization of each abnormal spermatozoon has thus, for a long time, been considered optional and partially redundant, an idea which is reflected in the earlier editions of the WHO manual. However, several recent studies have shown the importance of carefully assessing abnormal sperm morphology for use in the diagnosis ＆infertility, to determine fertility prognosis, and for basic or public health studies. One approach, which combines videomicroscopy and computer vision, and is the only approach able to assess the continuum of sperm biometrics, has been used successfully in several recent clinical, basic and toxicology studies. In summary, the visual assessment of detailed sperm morphology--including the categorization of anomalies allowing arithmetically derived indices of teratozoospermia--and the more modern computer-based approaches, although often considered to be redundant, are in fact complementary. The choice of the most appropriate method depends on the field of investigation （clinical, research, toxicology） and the problem being addressed. Each approach has advantages as well as certain limitations, which will be discussed briefly herein.

Human sperm quality and lipid content after migration into normal ovulatory human cervical mucus containing low numbers of leukocytes

The aim of this study was to investigate whether a relationship exists between the presence of low numbers of leukocytes in normal ovulatory cervical mucus and sperm quality and lipid content after migration. The percentages of live, motile and morphologically normal spermatozoa, movement parameters assessed by computer-aided sperm analysis （CASA）, and ionophore-induced acrosome reaction measured by flow cytometry were determined before and after migration. High-performance liquid chromatography with ultraviolet detection was used to measure the sperm lipid content, including the various diacyl subspecies. The number of leukocytes found in solubilized mucus samples was counted using a haemocytometric method. Overall, the presence of leukocytes in the cervical mucus samples did not significantly influence sperm motility and morphology, sperm kinematic parameters, or the sperm content in sphingomyelin or cholesterol. In contrast, after migration, the decrease in various sperm diacyls and the level of induced acrosome reaction was significantly less pronounced in mucus samples containing ≥10^4 leukocytes than in mucus samples with no or rare leukocytes whereas the level of induced acrosome reaction was higher. The present data suggest that the low level of leukocytes found in normal ovulatory cervical mucus could influence the process of sperm lipid remodelling/capacitation.

Integrative rodent models for assessing male reproductive toxicity of environmental endocrine active substances

In the present review, we first summarize the main benefits, limitations and pitfalls of conventional in vivo approaches to assessing male reproductive structures and functions in rodents in cases of endocrine active substance （EAS） exposure from the postulate that they may provide data that can be extrapolated to humans. Then, we briefly present some integrated approaches in rodents we have recently developed at the organism level. We particularly focus on the possible effects and modes of action （MOA） of these substances at low doses and in mixtures, real-life conditions and at the organ level, deciphering the precise effects and MOA on the fetal testis. It can be considered that the in vivo experimental EAS exposure of rodents remains the first choice for studies and is a necessary tool （together with the epidemiological approach） for understanding the reproductive effects and MOA of EASs, provided the pitfalls and limitations of the rodent models are known and considered. We also provide some evidence that classical rodent models may be refined for studying the multiple consequences of EAS exposure, not only on the reproductive axis but also on various hormonally regulated organs and tissues, among which several are implicated in the complex process of mammalian reproduction. Such models constitute an interesting way of approaching human exposure conditions. Finally, we show that organotypic culture models are powerful complementary tools, especially when focusing on the MOA. All these approaches have contributed in a combinatorial manner to a better understanding of the impact of EAS exposure on human reproduction.