Comparative Biochemistry and Physiology C-toxicology & Pharmacology最新文献

This study aimed to investigate the effects of 17α-Methyltestosterone (MT) on hepatic lipid metabolism in Gobiocypris rarus. G. rarus was exposed to varying concentrations of MT (0, 25, 50, and 100 ng/L) for durations of 7, 14, and 21 d. Biochemical and transcriptomic analyses were conducted using methods, such as ELISA, RT-qPCR, Western Blotting, and RNA-seq, to decipher the key signals and molecular mechanisms triggered by MT in vivo. The results revealed that MT induced hepatomegaly in G. rarus and markedly increased the hepatic steatosis index (HSI). After 14 d of exposure, significant increase in PPARγ mRNA expression was observed, whereas after 21 d, PPARα mRNA expression was significantly reduced. The expression pattern of SREBP1C mRNA initially decreased before increasing, mirroring the trend observed for SREBP1C protein expression. Furthermore, MT increased the levels of key lipid synthesis enzymes, including HSL, CPT1, GPAT, and FAS, thereby fostering lipid accumulation. RNA-seq analysis revealed that MT modulated hepatic bile acid metabolism via the PPAR pathway, consequently influencing cholesterol and lipid metabolism. Considering the differential metabolic pathways of MT across genders, it is postulated that MT may undergo aromatization to estrogen within G. rarus, thereby exerting estrogenic effects. These findings provide crucial experimental insights into the detrimental effects of MT in aquatic settings, underscoring its implications for safeguarding aquatic organisms and human health.

Abamectin (ABM) is a widely used pesticide in agriculture and veterinary medicine, which primarily acts by disrupting the neurological physiology of pests, leading to their paralysis and death. Its extensive application has resulted in contamination of many natural water bodies. While the adverse effects of ABM on the growth and development of non-target organisms are well documented, its impact on bone development remains inadequately studied. The present study aimed to investigate the effects of environmentally relevant concentrations of ABM (1, 5, 25 μg/L) on early bone development in zebrafish. Our results indicated that ABM significantly affected both cartilage and bone development of zebrafish larvae, accompanied by dose-dependent increase in deformity and mortality rates, as well as exacerbated apoptosis. ABM exposure led to deformities in the ceratobranchial (cb) and hyosymplectic (hs), accompanied by significant increases in the length of the palatoquadrate (pq). Furthermore, significant decreases in the CH-CH angle, Meckel's-Meckel's angle, and Meckel's-PQ angle were noted. Even at the safe concentration of 5 μg/L (1/10 of the 96 h LC₅₀), ABM delayed the process of bone mineralization in zebrafish larvae. Real-time fluorescent quantitative PCR results demonstrated that ABM induced differential gene expression associated with cartilage and bone development in zebrafish. Thus, this study provides preliminary insights into the effects and molecular mechanisms underlying ABM's impact on the bone development of zebrafish larvae and offers new evidence for a better understanding of its toxicity.

Time-restricted feeding (TRF) has the potential to modulate circadian rhythm and widely studied in humans and laboratory mice. However, less is known about the physiological responses to TRF in wild mammals. Here, we used Mongolian gerbils, Meriones unguiculatus, to explore the effect of 6-week TRF on gene expression related with circadian rhythm and inflammation. The TRF gerbils had higher cumulative food intake than the ad libitum (AL) group, but body mass, feeding frequency/time and metabolic rate did not differ between groups. In the hypothalamus, downregulation of rhythm-related genes Per3, Cry1 and Dbp was detected in the daytime-restricted feeding (DRF) group and Cry1 was downregulated in the nighttime-restricted feeding (NRF) group. In the liver, the expression of Per1/3, Rev-erbα/β and Dbp was lower, and Bmal1 was higher in the DRF than in AL group, while NRF gerbils showed no changes. In the colon, the expression of Bmal1 and Cry1 was higher but Per3, Rev-erbα/β and Dbp were lower in the DRF than in AL group. Further, the expression of inflammation-related genes such as NF-κB, IL-1β, IL-18 and Nlrp3 was lower in the liver of DRF gerbils, and IL-1β was lower both in the hypothalamus and liver of NRF gerbils. Moreover, the genes related with inflammation such as NF-κB, Nlrp3, IL-10/18/1β and Tnf-α were positively or negatively correlated with multiple rhythm-related genes in the central and peripheral organs. In conclusion, TRF, particularly DRF, could modulate rhythm-related genes in the central and peripheral tissues and reduce hepatic expression of inflammation-related genes in gerbils.

Ammonia is a major pollutant of freshwater environments. Previous studies have indicated that ammonia exposure adversely affects the physiology of freshwater fish. However, its effect on bone mineralization in freshwater fish larvae remains unclear. In this study, zebrafish larvae were used as a model to investigate the effects of different ammonia levels (0, 2.5, 5, and 10 mM NH₄Cl) on the survival rate, body length, and bone mineralization of fish. The survival rate of zebrafish embryos exposed to different NH₄Cl concentrations for 8 days was not affected. In contrast, the body length and bone mineralization of zebrafish larvae at 8 days post fertilization (dpf) were significantly reduced at 5 and 10 mM NH₄Cl exposure. Further investigations revealed that ammonia exposure decreased the mRNA expression of osteoblast-related genes and increased that of osteoclast-related genes. Additionally, exposure to 5 mM and 10 mM NH4Cl induced the production of reactive oxygen species (ROS). 10 mM—but not 5 mM—NH₄Cl exposure reduced the calcium and phosphorus content in 8 dpf zebrafish larvae. In conclusion, ammonia exposure induces bone resorption, while decreasing the calcium and phosphorus content of the whole body and bone formation, resulting in impaired bone mineralization in fish larvae.

Herbicide exposure poses a higher risk to reptiles due to their frequent contact with soil. Besides, food restriction is also a common environmental pressure that can seriously affect the survival of reptiles. The adaptive strategies of reptiles in the face of emerging herbicide pollution and food shortage challenges are not yet known. Therefore, Eremias Argus (a kind of small reptile) was selected as the model to simulate the real scenario of food shortage in lizards, aiming to explore the comprehensive impact of glufosinate-ammonium (GLA: an emerging herbicide) and food restriction on lizards. The results revealed that lizards often regulate their physiological and biochemical activities through body thermal selection and tend to choose lower body temperature, reduce digestibility, and actively participate in fat energy mobilization to avoid oxidative damage in the state of hunger, finally in order to achieve homeostasis. However, herbicide GLA disrupted the lizards' efforts to resist the stress of food shortage and interfered with the normal thermoregulation and energy mobilization strategies of lizards facing starvation. The results of this study would improve our understanding of the impacts of Lizards under extreme stresses, help supplement reptile toxicology data and provide scientific basis for the risk assessment of herbicide GLA.

Triphenyltin (TPT) is an organotin compound frequently detected in coastal estuaries, yet studies on TPT's effects in regions with significant salinity fluctuations, such as coastal estuaries, are currently limited. To investigate the toxic effects of TPT under different salinity conditions, this study focused on marine medaka (Oryzias melastigma) embryos. Through early morphological observations, RNA-seq analysis, biochemical marker assays, and qPCR detection, we explored the impact of TPT exposure on the early embryonic development of marine medaka under varying salinities. The study found that TPT exposure significantly increased embryo mortality at salinities of 0 ppt and 30 ppt. RNA-seq analysis revealed that TPT primarily affects glucose metabolism and glycogen synthesis processes in embryos. Under high salinity conditions, TPT may inhibit glucose metabolism by suppressing glycolysis and promoting gluconeogenesis. Furthermore, TPT exposure under different salinities led to the downregulation of genes associated with the insulin signaling pathway (ins, insra, irs2b, pik3ca, pdk1b, akt1, foxo1a), which may be linked to suppressed glucose metabolism and increased embryonic mortality. In summary, TPT exposure under different salinities affects the early development of marine medaka embryos and inhibits glucose metabolism. This study provides additional data to support research on organotin compounds in coastal estuaries.

Environmental implication