The Effect of Lead Acetate and Quercetin on the Tight and Gap Junctions in the Mouse Testis Parisa Dolati 1 & Zahra Khodabandeh 2 & Mohammad Javad Zamiri 1 & Iman Jamhiri 2 & Davood Mehrabani 2,3 Received: 17 January 2020 /Accepted: 11 February 2020 # Springer Science+Business Media, LLC, part of Springer Nature 2020 Abstract Environmental pollutant effects on fertility sometime are irretrievable. The aim of this study was to investigate the effect of lead acetate and quercetin on tight (claudin 11 and occludin) and gap junctional (connexin 43) proteins and the integrity of the blood– testis barrier status. Experimental groups, including the lead acetate (Pb), quercetin (QE), lead acetate with quercetin (Pb + QE), and control mice, were treated at least one spermatogenic cycle. Gene expression of claudin 11 and occludin decreased in Pb + QE, Pb, and QE compared with the control group. Connexin 43 (Cx43) expression in the control and Pb groups was lower than in Pb + QE and QE. The immunohistochemical data were generally in line with these findings. In conclusion, the results showed that Pb exposure led to disorders in cellular interactions that affect testicular function; however, simultaneous treatment with quercetin did not alleviate these effects. Keywords Heavy metals . Immunohistochemistry . Sertoli cells . Testosterone Introduction Environmental pollutants and stressors impact on the health and efficiency of the living organisms through their effects on the nervous [1], cardiovascular [2], immune [3], reproductive, and endocrine systems [4], leading to disorders in homeosta- sis. Approximately 15% of couples present some degrees of infertility [5], even infertility studies in males are undertaken easier than females; although, contribution of males infertility is equal with females [6, 7]. Semen quality has decreased during the last decades. The endocrine disruptors and environ- mental pollutants such as heavy metals, fertilizers, pesticides, and insecticides seem to be responsible for the general decline in semen quality [8]. Heavy metals (Pb, Hg, Cd, and As) are not degraded and are therefore considered as persistent envi- ronmental contaminants [9]. Globally, lead (Pb) is a ubiquitous, toxic, and widely dis- tributed environmental pollutant that affects almost every or- gan and cell in the body [10]. The effect of lead acetate on male reproduction has not been completely clarified, with most studies focusing on endocrine disorders [11], testicular structure [12], and sperm characteristics [13]. More recently, the effect of Pb on Sertoli cell, as a vital component of the testis involved in the development and maturation of germ cells, was reported [14–16]. One of the main mechanisms of lead-induced toxicity is oxidative stress, and it has been reported that natural antioxi- dant can reduce the toxicity of heavy metals [17–19]. Dietary bioflavonoids are considered as a large class of polyphenolic compounds in most plants. The flavonoids such as quercetin (3,3′,4′,5,7-pentahydroxyflavone) [20] are one of the most abundant flavonoids in fruits and vegetables which affect many biological systems especially the reproductive system [21], including the ovaries function [22], testes [23], and ac- cessory sex glands [24]. Quercetin is known as a potent natu- ral antioxidant via scavenging the free radicals (hydroxyl, per- oxide, and superoxide radicals) and their precursors, binding to metal ions and formation of chelates, xanthine oxidase blockage, and vitamin C absorption [25, 26, 27]. Various toxicants which impact on the blood–testis barrier (BTB), such as heavy metals, impair the male fertility [28]. In vivo studies confirmed that metals such as As, Cd, and Pb, can modify the tight and gap junction gene expression in * Zahra Khodabandeh Jahromi@sums.ac.ir 1 Department of Animal Science, College of Agriculture, Shiraz University, Shiraz, Iran 2 Stem Cells Technology Research Center, Shiraz University of Medical Science, Shiraz, Iran 3 Li Ka Shing Center for Health Research and Innovation, University of Alberta, Edmonton, AB, Canada Biological Trace Element Research https://doi.org/10.1007/s12011-020-02079-x