Toxicology of arsenate, arsenite, cadmium, lead, chromium, and nickel in testes of adult Swiss mice after chronic exposure by intraperitoneal route.

BACKGROUND: Some residues such as the heavy metals cadmium (Cd), lead (Pb), chromium (Cr VI), nickel (Ni), and arsenic (As), this last one in its oxidized forms + 5 (arsenate) and + 3 (arsenite), can cause injuries to human health, so they are currently considered environmental health emergencies. In the testis, heavy metals can cause morphological and functional damage due to constant exposure acting chronically in individuals. Thus, we aimed to determine the toxicological mechanism of As+5, As+3, Cd, Cr VI, and Ni that leads to testicular damage and establish for the first time an order of toxicity among these studied heavy metals. METHODS: Forty-two Swiss mice at reproductive age (140 days) were used, randomly distributed into seven experimental groups (n = 6). Exposure to heavy metals was weekly performed, by intraperitoneal route. Group 1 received 0.7 mL 0.9% saline (control), and the other groups received 1.5 mg/ kg of As+5, As+3, Cd, Pb, Cr VI, or Ni, for six weeks. RESULTS: These studied heavy metals did not accumulate in the testis tissue. However, exposure to Ni induced moderate pathologies in the seminiferous tubules, plus changes in the tunica propria, blood vessels, lymphatic space, and carbonyl protein levels. Cd exposure caused moderate tubular histopathologies and changes in the blood vessels and lymphatic space. Cr VI induced slight tubular histopathologies, changes in the lymphatic space, blood vessels, and SOD activity. Pb and As+3 exposure triggered moderate tubular pathologies and changes in the SOD activity and carbonyl protein levels, respectively. Finally, As+5 induced only slight tubular pathologies. CONCLUSION: The testicular histopathologies caused by the studied heavy metals are mainly triggered by changes in testicular oxidative balance. Based on our findings of histomorphological alterations, the toxicity order among the heavy metals is Ni>Cd>Cr(VI)>PbAs+3 >As+5. However, considering oxidative stress results, we propose the following testicular toxicity order for these heavy metals: Ni>As+3 > Cd>Cr(VI)>Pb>As+5. Ni exposure shows the most harmful among the heavy metals to the testis.

Relevance of the Isoflavone Absorption and Testicular Function: A Systematic Review of Preclinical Evidence.

Isoflavone is a phytoestrogen found in different types of food that can act as endocrine disrupters leading to testicular dysfunction. Currently, fragmented data on the action of this compound in the testicles make it difficult to assess its effects to define a safe dose. Thus, we systematically reviewed the preclinical evidence of the impact of isoflavone on testicular function. We also determined which form (aglycones or glycosylated) was the most used, which allowed us to understand the main biological processes involved in testicular function after isoflavone exposure. This systematic review was carried out according to the PRISMA guidelines using a structured search on the biomedical databases MEDLINE (PubMed), Scopus, and Web of Science, recovering and analyzing 22 original studies. The bias analysis and the quality of the studies were assessed by the criteria described in the risk of bias tool developed by SYRCLE (Systematic Review Centre for Laboratory Animal Experimentation). The aglycones and glycosylated isoflavones proved to be harmful to the reproductive health, and the glycosylates at doses of 50, 100, 146, 200, 300, 500, and 600 mg/kg, in addition to 190 and 1000 mg/L, appear to be even more harmful. The main testicular pathologies resulting from the use of isoflavones are associated with Leydig cells resulting from changes in molecular functions and cellular components. The most used isoflavone to evaluate testicular changes was the genistein/daidzein conjugate. The consumption of high doses of isoflavones promotes changes in the functioning of Leydig cells, inducing testicular changes and leading to infertility in murine models.