The decline in male reproductive health, characterized by diminishing sperm count and testosterone levels, has
raised concerns about environmental influences, particularly endocrine-disrupting chemicals (EDCs). Tris(2,3-
dibromopropyl)isocyanurate (TBC), a novel brominated flame retardant widely used in electronics, textiles,
and furniture, has emerged as a significant environmental contaminant with potential reproductive health im-
plications. In this study, we investigated the molecular mechanisms underlying TBC-induced reproductive
toxicity, particularly focusing on its impact on steroidogenesis and androgen signaling pathways using the GC-1
spg cell line as an in vitro model.
Exposure of GC-1 spg cells to TBC, alone or in combination with testosterone or the anti-androgen flutamide
resulted in decreased metabolic activity and increased lactate dehydrogenase release, indicating cytotoxic ef-
fects. Furthermore, TBC exposure led to a reduction in progesterone synthesis, while testosterone production
remained unaffected. Interestingly, estradiol synthesis was diminished after TBC exposure, suggesting a
disruption in steroid hormone balance critical for spermatogenesis. Mechanistic investigations revealed alter-
ations in key proteins involved in the non-classical testosterone pathway and steroidogenesis. TBC exposure
downregulated epidermal growth factor receptor (EGFR), protein kinase B (AKT), and phosphorylated cyclic
AMP response element-binding protein (p-CREB), indicating suppression of non-classical androgen signaling.
Additionally, decreased levels of steroidogenic acute regulatory protein (StAR) and 3-beta-hydroxysteroid de-
hydrogenase (HSD3β1) suggest impaired steroidogenesis. Here we uncover the intricate molecular mechanisms
underlying TBC-induced reproductive toxicity, highlighting its potential to disrupt steroid hormone synthesis and
androgen signaling pathways. Understanding the adverse effects of TBC on male reproductive health is crucial
for developing strategies to mitigate its environmental impact and safeguard human fertility.