Genetic and epigenetic modifications of F1 offspring’s sperm cells following in utero and lactational combined exposure to nicotine and ethanol

Abstract

It is well established that maternal lifestyle during pregnancy and lactation affects the intrauterine programming of F1 offspring. However, despite the co-use of alcohol and nicotine is a common habit, the effects of exposure to both substances on the reproductive system of F1 male offspring and the underlying mechanisms of developmental programming have not been investigated. The present study aimed to examine pre- and postnatal concurrent exposure to these substances on genetic and epigenetic alterations of sperm cells as well as testis properties of F1 offspring compared with exposure to each substance alone. Pregnant dams in the F0 generation randomly received normal saline, nicotine, ethanol, and combinations throughout full gestation and lactation periods. Sperm cells and testes of F1 male offspring were collected at postnatal day 90 for further experiments. High levels of sperm DNA fragmentation were observed in all exposed offspring. Regarding epigenetic alterations, there was a significant increase in the relative transcript abundance of histone deacetylase 1 and 2 in all exposed sperm cells. Moreover, despite a decrease in the expression level of DNA methyltransferase (DNMT) 3A, no marked differences were found in the expression levels of DNMT1 and 3B in any of the exposed sperm cells compared to non-exposed ones. Interestingly, combined exposure had less prominent effects relative to exposure to each substance alone. The changes in the testicular and sperm parameters were compatible with genetic and epigenetic alterations. However, MDA level as an oxidative stress indicator increased in all exposed pups, which may be responsible for such outputs. In conclusion, maternal co-exposure to these substances exhibited epigenotoxicity effects on germline cells of F1 male offspring, although these effects were less marked relative to exposure to each substance alone. These counteracting effects may be explained by cross-tolerance and probably less impairment of the antioxidant defense system.

In utero and postnatal exposure to Foeniculum vulgare and Linum usitatissimum seed extracts: modifications of key enzymes involved in epigenetic regulation and estrogen receptors expression in the offspring’s ovaries of NMRI mice

“…Complex molecular regulations during in utero development are a result of interactions between genetic and epigenetic. Maternal lifestyle [ 23 , 24 ], such as a dietary supplement with phytoestrogens is one of the environmentally epigenetic effect elements that could affect developmental programming processes [ 26 ]. However, maternal steroid hormone-binding protein (SHBG) and fetal α-fetoprotein are the main modifiers of fetal exposure to phytoestrogens that may protect the fetus partly from the destructive effects of exogenous estrogens such as phytoestrogens [ 31 ].…”

“…The synthesized cDNA was stored at -20 °C until use. Three replicates of qRT-PCR reactions were performed on a mixture consisted of 5 μl syber green Master Mix (Genaxxon bioscience, Ulm, Germany), 1 μl of each specific primers [ 23 ] (Table 1 ), and 2 μl of cDNA in a final volume of 10 μl. The program of q real-time PCR was as follows: initial denaturation at 95 °C for 40 s, followed by 35 cycles of denaturation at 95 °C for 20 s, 60 °C for 30 s, and final extension at 72 °C for 30 s using a Light Cycler Real-Time PCR System (MIC, Queensland, Australia).…”

“…Beta actin was assigned as the reference gene. All qPCR data were subsequently analyzed using the 2 _ΔΔCT method [ 23 ].…”

“…However, maternal lifestyle factors like diet [ 23 , 24 ], especially during the time of development, may change how genes are expressed via epigenetic phenomena. Because these changes are independent of genomic sequencing alteration, they may have an impact on future health or disease risk [ 25 , 26 ].…”

Developmental origins of adult diseases

“…Although human health is impaired by environmental exposure at any time, the potential effects of exposures during pregnancy are magnified during the most critical developmental period for male fetal development [ 151 ]. Maternal exposures to low dietary protein, high milk, alcohol, and nicotine [ 136 ] may adversely affect male fertility through epigenetic mechanisms [ 151 ]. Epidemiological and experimental studies have shown that exposure to a maternal low dietary protein during pregnancy reduces male fertility in adult male rats [ 130 ].…”