Diethylhexyl phthalate exposure amplifies oxidant and inflammatory response in fetal hyperglycemia model predisposing insulin resistance in zebrafish embryos.

Exposure of zebrafish embryos to glucose is a suitable model for the fetal hyperglycemia seen in gestational diabetes. Diethylhexyl phthalate (DEHP), which is considered an endocrine-disrupting chemical, is one of the most common phthalate derivatives used in stretching plastic and is encountered in every area where plastic is used in daily life. In the present study, the effects of DEHP on pathways related to insulin resistance and obesity were examined in zebrafish embryos exposed to glucose as a fetal hyperglycemia model. Zebrafish embryos were exposed to DEHP, glucose, and glucose + DEHP for 72 h post-fertilization (hpf), and developmental parameters and locomotor activities were monitored. At 72 hpf ins, lepa, pparγ, atf4a, and il-6 expressions were determined by RT-PCR. Glucose, lipid peroxidation (LPO), nitric oxide (NO) levels, glutathione S-transferase (GST), superoxide dismutase (SOD), and acetylcholine esterase (AChE) activities were measured spectrophotometrically. Compared with the control group, glucose, LPO, GST activity, il6, and atf4a expressions increased in all exposure groups, while body length, locomotor, and SOD activities decreased. While AChE activity decreased in the DEHP and glucose groups, it increased in the glucose + DEHP group. Although glucose exposure increased pparγ and lepa expressions, DEHP significantly decreased the expressions of pparγ and lepa both in the DEHP and glucose + DEHP groups. Our findings showed that DEHP amplified oxidant and inflammatory responses in this fetal hyperglycemia model, predisposing insulin resistance in zebrafish embryos.

White LED Light Exposure Inhibits the Development and Xanthophore Pigmentation of Zebrafish Embryo.

Circadian rhythm in all living organisms is disturbed continuously by artificial light sources and artificial lighting has become a hazard for public health. Circadian rhythm of melatonin maintains high levels of melatonin during the night and low levels during the day. N-acetyltransferase (arylalkylamine N-acetyltransferase, AANAT) is one of the four enzymes required for melatonin synthesis and mtnr1ba is a melatonin receptor-encoding mRNA that is expressed widely in the embryonic brain. Pax7 has important roles during neural crest development and especially xanthophore pigmentation. Due to its diurnal nature, zebrafish provide a special opportunity for research on circadian rhythms that are regulated by melatonin. Here in this study, we showed that when compared with the white light control group, white LED light exposure resulted in loss of yellow pigmentation, decreased body length and locomotor activity, oxidant-antioxidant imbalance and decreased expressions of aanat2, mtnr1ba, and pax7 in zebrafish embryos. Histological analysis of this group revealed disorganization of the spaces among photoreceptor cells, decreased total retinal thickness and photoreceptor cell layer thickness compared with the control group. Artificial lighting pollution has the potential to become an important risk factor for different diseases including cancer especially for industrialized countries, therefore, more studies should be performed and necessary regulations should be made regarding this risk factor.

Rotenone impairs oxidant/antioxidant balance both in brain and intestines in zebrafish.

AIM OF THE STUDY: Rotenone is a commonly used pesticide that inhibits complex I of the mitochondrial electron transport system. Rotenone exposed rats demonstrate many characteristics of Parkinson Disease (PD). Oxidative stress is one of the hallmarks of PD, being the major sources of ROS in the DA neurons. In recent years the strong connection between the intestinal environment and the function of the central nervous system (CNS) has gained widespread popularity. In order to explain the mechanism underlying the GI dysfunction in PD, we aimed to investigate oxidant-antioxidant status in the brain and intestine, as well as locomotor activity, in rotenone exposed zebrafish. MATERIALS AND METHODS: Adult zebrafish were exposed to 2 mg/L rotenone for 30 days. At the end of the experiment, locomotor activity was determined by simple observation. Lipid peroxidation (LPO), nitric oxide (NO) levels, superoxide dismutase (SOD), catalase (CAT) and glutathione-S-transferase (GST) activities were determined in the homogenates. RESULTS: Locomotor activity decreased in the rotenone exposed zebrafish. LPO increased in both brain and intestines whereas NO increased only in the brain. Decreased GST and CAT activities were found in both tissues whereas SOD activity decreased only in the intestines. CONCLUSION: As a conclusion, the results of our study support the connection between gut and brain axis in rotenone exposed zebrafish by means of oxidative stress and NO for the first time in literature.