Decreased Implantation Number After In Utero Artificial Insemination Can Reflect an Impairment of Fertility in Adult Male Rats After Exogenous Leptin Exposure

Abstract

Leptin is a protein secreted by the adipocytes, which serves as a link between fat and brain. Its main action is to decrease appetite and increase energy expenditure, but it is also involved in the control of different neuroendocrine systems, including gonadal axis. Although the effects of leptin deficiency on reproduction are well recognized, the effect of excess leptin on male reproductive function is not clear. The aim of this study was to evaluate fertility and sperm parameters of male rats exposed to exogenous leptin. A group of adult male rats received exogenous leptin intraperitoneally (30 μg/kg/day) for 42 days, and a control group received only the vehicle during the same period. After the treatment, animals were evaluated for sperm count, sperm motility, and fertility after intrauterine artificial insemination. There was no statistically significant difference between the groups related to sperm production, sperm concentration, and sperm motility. However, fertility evaluation after artificial insemination showed a quantitative decrease in the uterus plus fetuses weight, number of implantation sites, and number of live fetuses. The fertility potential showed a reduction of about 40%, whereas the preimplantation loss rate increased more than 2-fold in leptin-treated animals. In conclusion, leptin administration to nonobese male rats impairs ability of treated animals to generate offspring, since the occurrence of implantation was diminished. So leptin can impair sperm quality, affecting the reproductive capacity.

Exogenous leptin affects sperm parameters and impairs blood testis barrier integrity in adult male mice

“…However, leptin treatment hardly alters body weights or reproductive organ weights in normal rodents [ 14 , 16 – 19 , 43 ], also shown in this study, indicating that the effect on sperm parameters after leptin administration is unlikely due to leptin resistance [ 14 ]. Previous studies have reported that leptin treatment has no influence on serum leptin levels in normal rodents [ 14 , 18 ]. Although circulating leptin levels at 1 h after administration of 3 mg/kg leptin show a 170-fold increase in fasted mice and a 13-fold increase in fed mice, the half-life of mouse leptin is found to be 40.2 min [ 44 ].…”

“…In vitro experiments also show that leptin can directly reduce testosterone secretion and the expression of steroidogenic genes [ 12 , 39 , 48 ]. In normal rats, leptin treatment does not change serum testosterone significantly [ 14 , 18 ], although parenchymal testosterone decreases by about 49% compared with control rats [ 18 ]. Our study showed that 3 mg/kg leptin treatment repressed testicular steroidogenesis genes expression in vivo but did not produce a significant decrease in serum testosterone levels.…”

Human Amnion-Derived Mesenchymal Stem Cells Improved the Reproductive Function of Age-Related Diminished Ovarian Reserve in Mice Through Ampk/Foxo3a Signaling Pathway

“…The female mice were injected with 0.4% trypan blue solution (Gibco, 15250061) into the tail vein in E5.5, and the uterus was removed by abdominal surgery. The number of blue bands around uterine horns were counted [35] and gestation rate was calculated by formula: number of pregnant females/number of inseminated females [36].…”

Leptin and reproductive dysfunction in obese men

“…Current evidence, particularly from studies in the rat, points to the potential role of leptin in obesity‐related abnormalities in sperm parameters. For example, fertility potential of spermatozoa from Wistar rats following 42 days of leptin treatment was significantly lower than that of control rats (Fernandez et al, ). This same study also found that pre‐implantation embryo loss after artificial insemination in utero was also higher when spermatozoa from leptin‐treated Wistar rats were used, clearly linking leptin with the disturbed sperm parameters and fertility potential reported in obese men.…”