Male infertility is a worldwide issue that affects about 4–12% of men; it accounts about 20–70% of cases globally, with the highest incidence in Africa and Eastern Europe (Agarwal et al. 2015). There is mounting evidence that exposure to endocrine-disrupting chemicals like BPA is one of the factors that contributes to infertility and male reproductive problems (Cariati et al. 2019, Siracusa et al. 2018). In business, BPA is commonly used, especially in the production of polycarbonate plastics and food packaging, because it is strong and stable at high temperatures. PA is regarded as one of the substances used most frequently in industrially produced chemicals worldwide (Bosch et al. 2016). It contains a tiny (228 Da) particle, is white in colour, is a solid particle at room temperature, and smells of phenol. It has also been demonstrated that BPA has antagonistic effects on androgenic receptors, which are regarded to be the main regulators of androgen cell signaling. In particular, spermatogenesis, one of the most important processes, depends on androgen receptors for the growth and function of the male reproductive system (Siracusa et al. 2018).
The BPA-treated group's light microscopic findings revealed disorganization, disrupted seminiferous tubules, damaged spermatogonia containing vacuoles, Sertoli cells, and both primary and secondary spermatocytes. The interstitium contained the pleomorphic spermatids, aberrant interstitial cells, myoid cells and deformed blood capillaries. One of the detrimental effects of BPA on male fertility that have been noted in earlier studies is damage to testicular histoarchitecture, defective spermatogenesis as well as decreased LH and testosterone (Chianese et al. 2018, Ma et al. 2018). Findings point to a significant relationship between the paternal urine BPA content and the high prevalence of infertility treatment failure in the couple (Mínguez-Alarcón et al. 2021). DNA damage has been linked to an increased risk of infertility in elderly (Das et al. 2013, Rosiak-Gill et al. 2019), and the reduction in sexual and reproductive hormones (Belloc et al. 2014, Eisenberg &Meldrum 2017). The level of the hormone testosterone may be lowered due to interstitial cells that manufacture testosterone are dispersed throughout the connective tissue in between the coiled somniferous tubules (Akingbemi et al. 2004). An ultrastructural study of Sertoli cells revealed larger intracellular vacuoles, electron-dense bodies, expanded mitochondria, and cell debris, which supported these modifications (Gurmeet et al. 2014).
Seminiferous tubules from male BPA-treated rats were examined under an electron microscope, and some of the lining cells had severe cytoplasmic vacuolation (Gurmeet et al. 2014). These could be clarified by an ionic and osmotic imbalance that inhibits water from entering cells and causes cellular vacuolization; this is recognized as a type of cell ageing. Additionally, the expansion of the smooth endoplasmic reticulum, which may be a sign of alterations in cellular permeability, is possibly what causes the vacuolization of germinal and sustentacular cells. Additionally, it appeared from the ultrastructural data that several germinal cells in each rat exposed to BPA had undergone apoptosis. BPA caused degenerative alterations to the basement membrane, which preserves the testicular tissues' structural and functional integrity (Liu et al. 2013).
It's possible that BPA-induced lipid peroxidation and a drop in testosterone levels are what caused the ultrastructural abnormalities in the rat testis given BPA treatment. Where as in seminiferous tubules, testosterone is necessary for attachment of germ cells generations. As a result, low levels of testicular testosterone may cause germ cells disconnection from the seminiferous epithelium, which would then trigger to their death, that lead to male infertility (Blanco-Rodríguez &Martínez-García 1998). Numerous lines of research examine the protective role of natural and synthetic antioxidants in preventing the harmful effects of xenobiotic chemicals on the male reproductive system. As an endocrine disruptor, the tested substance caused oxidative stress in the testicles, liver, and kidney (Bindhumol et al. 2003, Rezvanfar et al. 2013). It is recognized that excessive reactive oxygen species (ROS) created in mitochondria and microcosms can cause oxidative stress, which can disrupt proteins, lipids, and nucleic acids. Numerous diseases, such as cancer, infertility, and neurological conditions, might result from this (Chitra et al. 2003, Kabuto et al. 2004).
According to the biochemical results, rats exposed to BPA exhibited significant changes in their enzyme activity, including an increase in MDA and a decrease in CAT and SOD.Data showed that BPA increased oxidative stress, altered levels of SOD and CAT, and induced aberrant interactions with radical oxygen in a range of biological systems (Aitken & Roman, 2008). Decreases in lipid peroxidation products like MDA can therefore cause antioxidant enzymes to become inhibited (Aitken &Roman 2008, Obata &Kubota 2000). Rong et al. (Rong et al. 2021)claimed that selenoprotein iodothyronine deiodinase upregulation results in high levels of ROS generation and altered antioxidant enzymes (CAT, SOD) performance. According to Tiwari &Vantage(Tiwari &Vanage 2017), the decline of numerous antioxidant enzymes, including SOD, CAT, and non-enzymatic reduced glutathione, is associated with a decline in sperm quality.
Khalaf et al. (Khalaf et al. 2019) showed that the dams of offspring testis had been subjected to BPA had higher levels of H2O2 & lipid peroxidation, and antioxidant defense systemsdepletion.BPA affected the morphology of the seminiferous tubule epithelium during the beginning of puberty, impairing sperm production and gonadotropin discharges. It also increased the ROS formation and decreased CAT and SOD antioxidant activity (Ullah et al. 2019).
Adult rats exposed to BPA had dose-dependently higher ROS levels, and the loss of essential proteins insulin receptor substrate-2 and glucose transporter-8 in the testicles—respectively necessary for spermatogenesis and testicular energy metabolism—proved that metabolic dysfunction and oxidative stress were linked to reproductive system dysfunction (D'Cruz et al. 2012). Adult rats' epididymis, testicles, and immunological cells (lymphocytes and bone marrow) all showed a considerable rise in lipid peroxidation as a result of BPA exposure.
Previous studies have shown that BPA has detrimental effects on the male genital system; 15 days of oral exposure resulted in a reduction in the number of spermatocytes, Leydig cells, serum testosterone, and the testis' overall antioxidant capacity (Yousaf et al. 2016). Wang et al. (2014) found that BPA administration decreased sperm production while increasing caspase-9 and − 3 activity and TUNEL-positive cells. antioxidant capabilities are a feature of CoQ10 and its effects on lipid peroxidation, antioxidant defenses that had been compromised, and arsenic-induced rise in caspase-3 levels were all dramatically reduced (Fouad et al. 2011). Based on the findings of cited studies, BPA and CoQ10 dosages and treatment durations were chosen (Wang et al. 2014, Yousaf et al. 2016).
Comparing the groups who received BPA with CoQ10 to those that received BPA alone, the data obtained showed a noticeably improved testicular structure. The outcomes also demonstrated that CoQ10 treatment reduced MDA while increasing CAT and SOD activity. A considerable reduction in testicular MDA levels was seen after treatment with CoQ10 in comparison to the BPA group and an increase in testicular SOD. These results are in line with the preceding research (Saleh et al. 2017). According to Saleh et al.(Saleh et al. 2017), CoQ10 supplementation dramatically reduced ROS levels. CoQ10 is a powerful antioxidant. The byproducts of lipid peroxidation during free radical reactions are scavenged by CoQ10 (Sohet et al. 2009) and prevents the production of ROS (Sohet et al. 2009, Tsuneki et al. 2007). An important cellular antioxidant is CoQ10 with the ability to reduce inflammation and scavenge free radicals (Chen et al. 2019, Lamia et al. 2021). Following exercise training, CoQ10 can modify the nuclear factor's production erythroid 2-related factor 2 (Nrf2), supporting its function in inflammation and antioxidant defense (Pala et al. 2016).