Lead, a chemical element in the carbon group with symbol Pb (from Latin: Plumbum, meaning “the liquid silver”) and has an atomic number 82 in the periodic table. It was the first element that was characterized by its kind of toxicity. In animal systems, lead (Pb) has been incriminated in a wide spectrum of toxic effects and it is considered one of the persistent ubiquitous heavy metals. Being exposed to this metal could lead to the change of testicular functions in human beings as well as in the wildlife. The lead poising is a real threat to the public health, especially in the developing countries. Accordingly, great efforts on the part of the occupational and public health have been taken to curb the dangers of this metal. Hematopoietic, renal, reproductive, and central nervous system are among the parts of the human body and systems that are vulnerable toward the dangers following exposure to high level of Pb. In this review, we discussed the massive harmful impact that leads acetate toxicity has on the animals and the worrying fact that this harmful toxicant can be found quite easily in the environment and abundance. Highlighting its (Pb) effects on various organs in the biological systems, its economic, as well as scientific importance, with the view to educate the public/professionals who work in this area. In this study, we focus on the current studies and research related to lead toxicity in animals and also to a certain extent toward human as well.

No abstract

In this study, isolated spermatogonial stem cells (SSCs) and Sertoli cells using enzymatic digestion from patients with maturation arrest of spermatogenesis were grown in Dulbecco's modified Eagle's medium (DMEM) supplemented with 10% foetal calf serum in three different groups: (1) SSCs cultured without Sertoli cells (2) SSCs co-cultured with Sertoli cells (as control group), (3) SSCs co-cultured with Sertoli cells and adding different concentrations of basic fibroblast growth factor (0.1, 1, 10 ng ml(-1)) and human leukaemia inhibitory factor (1000, 1200, 1500 unit ml(-1)) as experimental groups. The assessment of colonies every 10 days during 5-week cultures showed that in the first group, the average number and diameter of the colonies were significantly lower than in the other groups (P < 0.05). The largest number of colonies was observed in control condition (32.29 ± 9.15) in day 30. The largest diameter of colonies was formed in combination dosages of 1 ng ml(-1) basic fibroblast growth factor (bFGF) + 1500 unit ml(-1) leukaemia inhibitory factor (LIF) (302.93 ± 37.68) and 10 ng ml(-1) bFGF and 1200 unit ml(-1) LIF (262.87 ± 35.54) in day 30 respectively. Isolated SSCs were positive for spermatogonial cell markers such as Oct4, Stra8, Piwil2 and Vasa but negative for Nanog. Transplantation technique indicated that hSSCs have good efficiency for colonisation of mouse seminiferous tubules after proliferation in culture system.

In order to improve Boer goat semen quality during cryopreservation process, the influence of sugar supplementation on semen characteristics of sperm were investigated. Three experiments were carried out to investigate the effect of (a) addition of two monosaccharides (fructose and glucose) and two disaccharides sugars (trehalose and sucrose) (b) sugar combination (fructose and trehalose, sucrose and trehalose, glucose and trehalose), and control (glucose without trehalose) (c) different concentrations of trehalose on cryopreservation using Tris based extender. The total motility, forward motility, viability, normal spermatozoa, acrosome integrity and membrane integrity were assessed subjectively. Differences were not detected among monosaccharides, but glucose increased (P<0.05) sperm forward motility in post-thaw goat semen compared to trehalose or sucrose supplementation. Semen quality did not differ (P>0.05) among disaccharide sugar supplementation. Combination of glucose and trehalose significantly improved the characteristics of Boer spermatozoa after cryopreservation (P<0.05). Supplementation of trehalose (198.24mM) into the glucose extender significantly increased total motility, forward motility, live spermatozoa, acrosome integrity and membrane integrity following cryopreservation (P<0.05). In conclusion, glucose had the better ability to support Boer sperm motility and movement patterns. Combination of monosaccharide (glucose) and disaccharide (trehalose) improved semen quality following cryopreservation. Trehalose supplementation at the concentration of 198.24mM to the glucose extender conferred the greater improvement of semen quality for Boer semen cryopreservation.

This study was conducted to determine the effect of antioxidants on standard semen parameters, lipid peroxidation and fertility of Boer goat semen after cryopreservation. Ejaculates from four bucks were collected, evaluated and pooled at 37°C. The pooled semen was diluted with Tris citric acid fructose for washing. Semen samples, which were diluted with a Tris-based extender containing the antioxidant ascorbic acid (8.5mg/ml), butylated hydroxytoluene (2mM), cysteine (5mM) and hypotaurine (10mM) and an extender without antioxidant supplementation were cooled to 4°C and frozen in 0.25 straws with programmable freezer and finally stored in liquid nitrogen. Data (10 replicates) were analyzed by one-way analysis of variance. Mean (±SEM) progressive motility was significantly higher in ascorbic acid than other supplement groups and control samples (P>0.05). Best values were observed in ascorbic acid followed by BHT, cysteine, and hypotaurine. Antioxidant supplementation in extender showed significant (P<0.05) better values than the control group for sperm membrane integrity, acrosome integrity and viability. The ability of antioxidants to reduce the lipid peroxidation (LPO) after freeze thawing was measured by the formation of malondialdehyde (MDA) using the thiobarbituric acid method. Results showed that addition of antioxidants significantly reduced the rate of LPO in comparison to control (P<0.05). Ascorbic acid exhibited better values (1.27±0.28), than butylated hydroxytoluene, cysteine and hypotaurine 1.32±0.42, 2.27±0.16 and 2.38±0.17 respectively, which are significantly better than control (3.52±0.54). Higher pregnancy rate was observed with ascorbic acid followed by butylated hydroxtolune, hypotaurine and cysteine. However, differences in the fertility rate were non-significant with hypotaurine, cysteine and control groups.