Icariside II reduces testosterone production by inducing necrosis in rat Leydig cells

Atrazine exposure causes mitochondrial toxicity in liver and muscle cell lines

Objective:

Chronic exposure to atrazine and other pesticides is reported to cause metabolic disorders, yet information on effects of atrazine on expression of genes relevant to mitochondrial function is largely missing. In the present study, therefore, we investigated the expression of a battery of nuclear- and mitochondrial-encoded genes involved in oxidative phosphorylation (OXPHOS) in human liver (HepG2) and rat muscle (L6) cell lines due to short-term atrazine exposure.

Materials and Methods:

We have determined the EC₅₀ values of atrazine for cytotoxicity and mitochondrial toxicity (mitotoxicity) in terms of adenosine triphosphate (ATP) content in HepG2 and L6 cells. Further, the mRNA expression of nuclear- and mitochondrial-encoded genes was analyzed using quantitative real-time polymerase chain reaction.

Results:

The EC₅₀ value of atrazine for mitotoxicity in HepG2 and L6 cells was found to be about 0.162 and 0.089 mM, respectively. Mitochondrial toxicity was indicated by reduction in ATP content following atrazine exposure. Atrazine exposure resulted in down-regulation of many OXPHOS subunits expression and affected biogenesis factors’ expression. Most prominently, superoxide dismutase (SOD) and sirtuin 3 (SIRT3) expressions were up-regulated in HepG2 cells, whereas SIRT3 expression was alleviated in L6 cells, without significant changes in SOD levels. Mitochondrial transcription factor A (TFAM) and SIRT1 expression were significantly down-regulated in both cell lines.

Conclusion:

Results suggest that TFAM and SIRT1 could be involved in atrazine-induced mitochondrial dysfunction, and further studies can be taken up to understand the mechanism of mitochondrial toxicity. Further study can also be taken up to explore the possibility of target genes as biomarkers of pesticide toxicity.

Mice lacking β-carotene-15,15'-dioxygenase exhibit reduced serum testosterone, prostatic androgen receptor signaling, and prostatic cellular proliferation

β-Carotene-15,15'-dioxygenase (BCO1) cleaves dietary carotenoids at the central 15,15' double bond, most notably acting on β-carotene to yield retinal. However, Bco1 disruption also impacts diverse physiological end points independent of dietary carotenoid feeding, including expression of genes controlling androgen metabolism. Using the Bco1^-/- mouse model, we sought to probe the effects of Bco1 disruption on testicular steroidogenesis, prostatic androgen signaling, and prostatic proliferation. Male wild-type (WT) and Bco1^-/- mice were raised on carotenoid-free AIN-93G diets before euthanasia between 10 and 14 wk of age. Weights of the prostate and seminal vesicles were significantly lower in Bco1^-/- than in WT mice (-18% and -29%, respectively). Serum testosterone levels in Bco1^-/- mice were significantly reduced by 73%. Bco1 disruption significantly reduced Leydig cell number and decreased testicular mRNA expression of Hsd17b3, suggesting inhibition of testicular testosterone synthesis. Immunofluorescent staining of the androgen receptor (AR) in the dorsolateral prostate lobes of Bco1^-/- mice revealed a decrease in AR nuclear localization. Analysis of prostatic morphology suggested decreases in gland size and secretion. These findings were supported by reduced expression of the proliferation marker Ki-67 in Bco1^-/- prostates. Expression analysis of 200 prostate cancer- and androgen-related genes suggested that Bco1 loss significantly disrupted prostatic androgen receptor signaling, cell cycle progression, and proliferation. This is the first demonstration that Bco1 disruption lowers murine circulating testosterone levels and thereby reduces prostatic androgen receptor signaling and prostatic cellular proliferation, further supporting the role of this protein in processes more diverse than carotenoid cleavage.