Structure and gene expression changes of the gill and liver in juvenile black porgy (Acanthopagrus schlegelii) under different salinities.

Black porgy (Acanthopagrus schlegelii) is an important marine aquaculture species in China. It is an ideal object for the cultivation of low-salinity aquaculture strains in marine fish and the study of salinity tolerance mechanisms in fish because of its strong low-salinity tolerance ability. Gill is the main osmoregulatory organ in fish, and the liver plays an important role in the adaptation of the organism to stressful environments. In order to understand the coping mechanisms of the gills and livers of black porgy in different salinity environments, this study explored these organs after 30 days of culture in hypoosmotic (0.5 ppt), isosmotic (12 ppt), and normal seawater (28 ppt) at histologic, physiologic, and transcriptomic levels. The findings indicated that gill exhibited a higher number of differentially expressed genes than the liver, emphasizing the gill's heightened sensitivity to salinity changes. Protein interaction networks and enrichment analyses highlighted energy metabolism as a key regulatory focus at both 0.5 ppt and 12 ppt salinity in gills. Additionally, gills showed enrichment in ions, substance transport, and other metabolic pathways, suggesting a more direct regulatory response to salinity stress. The liver's regulatory patterns at different salinities exhibited significant distinctions, with pathways and genes related to metabolism, immunity, and antioxidants predominantly activated at 0.5 ppt, and molecular processes linked to cell proliferation taking precedence at 12 ppt salinity. Furthermore, the study revealed a reduction in the volume of the interlamellar cell mass (ILCM) of the gills, enhancing the contact area of the gill lamellae with water. At 0.5 ppt salinity, hepatic antioxidant enzyme activity increased, accompanied by oxidative stress damage. Conversely, at 12 ppt salinity, gill NKA activity significantly decreased without notable changes in liver structure. These results underscore the profound impact of salinity on gill structure and function, highlighting the crucial role of the liver in adapting to salinity environments.

Protective properties of tanshinone I against oxidative DNA damage and cytotoxicity.

Tanshinone I, a naturally occurring diterpene from Danshen, has been shown to possess hepatocyte protective, anticancer, and memory enhancing properties. However, there are few stringent pharmacological tests for neuroprotection of tanshinone I thus far. Since peroxynitrite is involved in the pathogenesis of neurodegenerative disorders, this study was undertaken to investigate whether the neuroprotective effect of tanshinone I is associated with inhibition of peroxynitrite-caused DNA damage, a critical event leading to peroxynitrite-induced cytotoxicity. Our results show that tanshinone I can significantly inhibit peroxynitrite-induced DNA damage both in φX-174 plasmid DNA and rat primary astrocytes. EPR spectroscopy indicates that tanshinone I potently diminished the DMPO-hydroxyl radical adduct signal from peroxynitrite. Taken together, these results demonstrate for the first time that tanshinone I can protect against peroxynitrite-induced DNA damage, hydroxyl radical formation and cytotoxicity, which might have implications for tanshinone I-mediated neuroprotection.