Oxidative stress, genotoxicity and histopathology biomarker responses in Mugil cephalus and Dicentrarchus labrax gill exposed to persistent pollutants. A field study in the Bizerte Lagoon: Tunisia.

The use of biomarkers has become an important tool for modern environmental assessment as they can help to predict pollutants involved in the monitoring program. Despite the importance of fish gill in several functions (gaseous exchange, osmotic and ionic regulation, acid-base balance and nitrogenous waste) its use in coastal water biomonitoring focusing on protection and damage is scarce. This field study investigates biochemical (catalase, superoxide dismutase, lipid peroxidation), molecular (DNA integrity) and morphological (histology) parameters in gill of mullet (Mugil cephalus) and sea bass (Dicentrarchus labrax) and originating from Bizerte lagoon (a coastal lagoon impacted by different anthropogenic activities) and from the Mediterranean Sea (a reference site). Remarkable alterations in the activities of oxidative stress enzymes and DNA integrity in the tissue of the two studied fish species were detected in Bizerte Lagoon. The study of histopathological alterations of gills in both two fish species from Bizerte Lagoon suggest thickening of primary lamellae, cellular hyperplasia, aneurism, curving, shortening and fusion of secondary lamellae. The adopted approach, considering simultaneously protection responses and damaging effects, revealed its usefulness on the pollution assessment.

Oxidative stress, genotoxicity and histopathology biomarker responses in mullet (Mugil cephalus) and sea bass (Dicentrarchus labrax) liver from Bizerte Lagoon (Tunisia).

The aim of the study was to evaluate the impact of environmental contaminants on oxidative stress, genotoxic and histopathologic biomarkers in liver of mullet (Mugil cephalus) and sea bass (Dicentrarchus labrax) collected from a polluted coastal lagoon (Bizerte Lagoon) in comparison to a reference site (the Mediterranean Sea). Antioxidant enzyme activities were lower in fish from the polluted site compared with fish from the reference site, suggesting deficiency of the antioxidant system to compensate for oxidative stress. DNA damage was higher in both fish species from the contaminated site indicating genotoxic effects. The liver histopathological analysis revealed alterations in fish from Bizerte Lagoon. Hepatocytes from both fish species featured extensive lipid-type vacuolation and membrane disruption. Results suggest that the selected biomarkers in both fish species are useful for the assessment of pollution impacts in coastal environments influenced by multiple pollution sources.

Chronic exposure to MDMA (ecstasy) increases DNA damage in sperm and alters testes histopathology in male rats.

3,4-Methylenedioxymethamphetamine (MDMA or "ecstasy") is consumed mainly by young population. For this reason, it is especially relevant to take into consideration the effects on the reproductive system. The influence of MDMA on the fertility and reproduction of the male rat was assessed in this study. MDMA was administered subcutaneously at 0 mg/kg (control), 0.5 mg/kg, 5 mg/kg and 10 mg/kg to SD male rats once a day, 3 consecutive days a week during 12 weeks, simulating human weekend associated consumption. Hormonal, haematological, biochemical, histological, genotoxicological and testicular and sperm parameters were evaluated in half of the rats. The remaining animals were mated with untreated sexually receptive females to evaluate the mating and pregnancy rates. A significantly higher incidence of DNA damage in Comet Test in sperm, tubular degeneration and interstitial oedema in testes was found. At all doses tested, sperm motility, morphology, mating and pregnancy rates, and number of implantation sites were not affected. This study fills the existing gap of knowledge about the chronic effects of MDMA in reproductive function using a realistic experimental design. Taking into account the higher sensitivity of human males, some concerns about the effects on the reproductive health still remain.