Apoptosis in HepG2 cells induced by zinc pyrithione via mitochondrial dysfunction pathway: Involvement of zinc accumulation and oxidative stress.

Zinc pyrithione (ZPT) is widely used as a substitute booster biocide for tributyltin and is also an additive to antidandruff shampoos and medical cosmetic products. ZPT and pyrithione have been detected in different environmental matrices and biota, suggesting that it may pose health threats to aquatic organisms and even humans. The present study used HepG2 cells, a human hepatoma cell line, to study the hepatotoxicity of ZPT (0.1-5.0 µM). ZPT treatment caused marked viability reduction and induced apoptosis depending on its dose used. ZPT-induced apoptosis involved an increased Bax/Bcl-2 ratio, loss of mitochondrial membrane potential, cytochrome c release, and enhanced caspase-9/-3 activity. In addition, a significant elevation in the amount of zinc ions and oxidative stress was evident. The involvement of these in ZPT-induced apoptosis was confirmed by toxicity comparison with analogs of ZPT and the observation that pretreatment with antioxidants afforded protection. Overall, these results suggest that ZPT induces zinc accumulation, oxidative stress, and subsequent apoptosis by causing mitochondrial dysfunction. Importantly, ROS was an initial and prolonged signal in ZPT-induced apoptosis in HepG2 cells.

A framework for the assessment of the spatial and temporal patterns of threatened coastal delphinids.

The massively accelerated biodiversity loss rate in the Anthropocene calls for an efficient and effective way to identify the spatial and temporal dynamics of endangered species. To this end, we developed a useful identification framework based on a case study of locally endangered Sousa chinensis by combining both LEK (local ecological knowledge) evaluation and regional boat-based survey methods. Our study investigated the basic ecological information of Sousa chinensis in the estuaries of eastern Guangdong that had previously been neglected, which could guide the future study and conservation. Based on the statistical testing of reported spatial and temporal dolphins sighting data from fishermen and the ecological monitoring analyses, including sighting rate, site fidelity and residence time estimations, some of the current Sousa chinensis units are likely to be geographically isolated and critically endangered, which calls for much greater conservation efforts. Given the accelerated population extinction rate and increasing budgetary constraints, our survey pattern can be applied in a timely and economically acceptable manner to the spatial and temporal assessment of other threatened coastal delphinids, particularly when population distributions are on a large scale and traditional sampling methods are difficult to implement.