Sperm quality

Male B6C3F1 mice (10 per group) were administered total doses of 0.2, 0.5 or 1 mg sodium chlorite by gavage in five equal daily doses. Positive controls received 200 mg ethyl methanesulfonate/kg bw intraperitoneally in five equal doses. Animals were sacrificed 1,3 and 5 weeks after dosing, and the caudae epididymides were removed and diced in saline. Tissue fragments were filtered out, and 1000 

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The issue of whether sperm counts are declining has been the focus of most media attention. A debate still continues as to whether the reported changes in sperm quality are genuine. In 1992, an article described the meta analysis of available data on semen quality in normal men, taken from reports published between the period 1938-1990. This analysis showed a 50% decline in sperm concentration... 

Lifeng T, Shoulin W, Junmin J et al (2006) Effects of fenvalerate exposure on sperm quality among occupational workers. Contraception 73 92-96... 

Hurtt ME, Working PK. 1988. Evaluation of spermatogenesis and sperm quality in the rat following acute inhalation exposure to methyl bromide. Fundam AppI Toxicol 10 490-498. 

There has been some concern that the recently observed decline in sperm quality may be related to exposure to environmental estrogens (Sharpe and Skakkebaek, 1993) and at the same time there has been speculation that these estrogenic compounds may exert inhibitory effects against prostate cancer (Kurzer, 2002). Theoretically, exposure to high levels of dietary estrogens could alter the hypothalamic-pituitary-gonadal axis in men, but dietary studies to date have not shown such an hormonal effects. 

Estms cyclicity and sperm quality Pregnancy outcome, e.g., dystocia Growth, development, and viability of offspring Anogenital distance if triggered Sexual maturation... 

Two major systems have been identified as toxicity targets for 1,3-DNB the red blood cell and the male reproductive system (see Section 2.2.2). In the red blood cell, 1,3-DNB induces formation of methemoglobin leading to cyanosis (Blackburn et al. 1988 Linder et al. 1988, 1990 Reader et al. 1991). In the male reproductive system, 1,3-DNB causes disruption of spermatogenesis resulting in hypospermia, poor sperm quality, and infertility (Blackburn et al. 1988 Hess et al. 1988 Linder et al. 1988). Whether adverse hematological and reproductive effects are caused by the same mechanism of action remains unresolved. 

Carlsen E., A. Ginerchman, N. KeidUng, and N.E. Skakkebaek (1995). Declining sperm quality and increasing incidence of testicular cancers Is there a common cause Environmental Health Perspectives 130 137-139. 

In healthy men, chronic melatonin administration (> 6 months) decreased sperm quality, possibly by aromatase inhibition in the testes. Until more is known, melatonin should not be used by couples who are actively trying to conceive. 

Fecundity, fertility and sperm quality are distinct parameters that are not equivalent and are frequently confused. Sperm count and... 

In one of the first studies of data collected about sperm quality over time, Carlsen and coworkers analyzed 61 sperm-count studies from several countries published between 1938 and 1991 and showed that there was a significant decrease in mean sperm count from X 106/ml in 1940 to 66 X 106/ml in 1990 (p <... 

The work by Fisch and coworkers on sperm quality of men from vasectomy clinics in New York, California, and Minnesota revealed no change in sperm counts, sperm volume, or sperm motility in the period 1970 through 1994.18 They did, however, show surprisingly large differences in sperm counts between the three locations. Sperm counts in New York, California, and Minnesota were 131.5,72.7, and 100.8 x 106/ml, respectively, and still... 

A number of investigators have evaluated the role of vitamin E and have reported improved sperm quality in controlled and uncontrolled trials (Geva et al., 1996 Kessopoulou et al., 1995 Suleiman et al., 1996). In a small placebo-controlled trial, Lenzi et al. (1998) have reported that glutathione... 

While comprehensive research and surveys were delayed, or lacking, no significant effort had been put toward the overview of the existing data of emissions, sources, distribution, exposure, and fate of POPs. Lee and Kim (1999) collected published data on concentrations of EDCs for almost all environmental media and human tissues and performed a meta-analysis to examine the relationship between the sperm quality of South Korean... 

Lee, D.S., Kim, R.H., 1999. Exposure route of endocrine disrupting compounds and estimation of alteration in Korean male s sperm quality (meta-analysis). Kyobo Foundation of Education Culture (in Korean). Seoul, Korea. 

Variations in sperm quality among individual males within a strain are common. 

Reduced fertility has been found for a number of chemicals, but often at relatively high exposure levels. However, it has to be considered that the rat is the most commonly used experimental animal and that a male rat can generally still produce normal progeny after having its sperm production reduced to 10% of the normal level (Aafjes et al., 1980). Thus, fertility data from rat studies alone can be a rather insensitive end-point. Human males may not have a similar sperm reserve capacity as rodents, and therefore the two-generation study has recently been updated to include assessment of sperm quality. It is unknown whether female rats (compared with human females) are also less sensitive to effects on fertility, but the two-generation study has recently been updated in that aspect by the inclusion of assessment of estrous cyclicity. 

The assessment of sperm quality includes measures of sperm number, anomalies, and motility, but the ability of the sperm to fertilize the ovum is not assessed. In order to increase the sensitivity for detection of fertility effects, investigation of in vitro fertilization could be considered. Another potentially more sensitive option may be the continuous breeding protocol, where the animals produce several litters instead of only one litter per pair. 

Human patients with impaired sperm qualities... 

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