Fluorescence microscopy observations have indicated that silicon-based QDs were present and accumulated in the hepatic tissue at all time intervals (1, 3, and 7 days) (XAV939 Figure 1B,C,D). The most intense accumulation was detected 7 days after IP injections, in hepatocytes

around blood vessels (Figure 1D). A histological assessment was performed to determine if silicon-based QDs accumulation cause liver damage. Figure 1 QDs localization and accumulation in the liver of Carassius gibelio is highlighted by fluorescence microscopy. When excited in UV, the DAPI-stained nuclei appear blue, while the Si/SiO2 QDs appear Selleck Repotrectinib red due to their intrinsic fluorescence. (A) Liver tissue from control (non-injected) animals. QDs are visible in the hepatocytes at 24 h (B), 72 h (C), and 7 days (D) after IP injection (arrows). The livers of control fish showed normal histology (Figure 2A). Fish liver is composed of branching and anastomosing cords of polygonal CBL0137 hepatocytes, with a central, dictinctive, and hyperchromatic nucleus, with a visible nucleolus. To be more specific, extensive vacuolations are observed, a characteristic of cultured fish hepatocytes, which often become swollen with glycogen or neutral fat. In the liver of fish injected with silicon-based QDs, we observed

some hystological alterations. Although functional phagocytic cells are occasionally observed in the sinusoids of healthy liver tissue, after 1 day of QDs exposure, we highlight an increased number of macrophage cluster (Figure 2B). Aggregates of Carnitine dehydrogenase macrophages are involved in recycling, sequestration, and detoxification of endogenous and exogenous compounds [51–53]. Several pathological states such as starvation [53], parasite attack [54], nutritional imbalances [55], and hemolytic

anemias [53], can enhance macrophage aggregate appearance. After 3 days, the proliferation of fibrous connective tissue near sinusoids occurred, substituting liver parenchyma (Figure 2C). Hepatic fibrosis appeared, probably due to the accumulation of extracellular matrix components [56]. Oxidative stress induces fibroblast [57] and hepatic stellate cell proliferation [58] and also collagen synthesis [59]. Hepatocyte basophilia and pronounced destruction of the liver arhitecture at 7 days after IP injection were observed (Figure 2D). The cummulative effects produced by Si/SiO2 QDs accumulation are possibly causing a certain degree of hepatic insufficiency in gibel carp. Nonetheless, only a reduced healthy hepatic parenchyma is required to maintain normal liver function [60]. Oxidative stress markers The silicon quantum dots uptaken in the liver could interact with NADPH oxidase in plasma membrane, thus generating superoxide in the extracellular space [61], which would enter the cells through an anion channel [62].