Nuestro último artículo, publicado en Marine Environmental Research

Sex-specific reproductive impairment in Pacific oysters (Magallana gigas) exposed to TiO₂ NPs: a focus on gonadal quality

Fátima Fernández-García, Ana Marques, Soraia Jerónimo, Isabel B. Oliveira, Ana Carvalhais, Vitoria Pereira, Juan F. Asturiano, Mário Pacheco, Cláudia Mieiro

Abstract

Environmentally realistic concentrations of titanium dioxide nanoparticles (TiO₂ NPs) are considered reprotoxic for marine bivalves. However, further investigation is needed to understand their impact on gonadal health, particularly concerning sex-specific responses. Thus, this study aimed to understand sex-based effects of TiO₂ NPs environmentally realistic concentrations in the gonad of Pacific oysters (Magallana gigas). Oysters were exposed to 10 and 100 μg.L^-1 of TiO₂ NPs for 3 and 7 days. Morphological parameters (condition index, sex and gametogenic stage), energy-related responses (carbohydrates, lipids, proteins, and electron transport system (ETS) activity), digestive function (alpha-amylase activity), and oxidative stress profile (antioxidants and damage) were assessed to address gonadal status. The results revealed sex-specific responses based on duration and concentration. Females reflected a drop in carbohydrate levels after 3 days at 100 μg.L^-1, suggesting mobilization of this energy reserve to counteract TiO₂ NP effects, followed by recovery after 7 days. Males showed reduced metabolic activity after 3 days at 10 μg.L^-1, marked by ETS depletion, independently of oxidative stress demonstrating a compensatory response to TiO₂ NP exposure. After 7 days, both concentrations triggered male lipid peroxidation despite carbohydrate mobilization at 10 μg.L^-1, indicating oxidative damage in testes. These findings revealed that TiO₂ NPs are reprotoxic for male oysters at 10 μg.L^-1, through oxidative stress pathways, while females reflected vulnerability to 100 μg.L^-1. This study provides valuable insights into understanding TiO₂ NP's reprotoxicity at environmental concentrations, highlighting gonads as a target for these NPs, and their potential risks to marine bivalves.

doi: 10.1016/j.marenvres.2025.107008