Role of miR-731 and miR-2188-3p in mediating chlorpyrifos induced head kidney injury in common carp via targeting TLR and apoptosis pathways.

Chlorpyrifos (CPF) is an environmental pollutant with increasing importance due to its high toxicity to fish and aquatic animals. In the present study, we divided 120 common carp (Cyprinus carpio L.) into two groups including control group and CPF group, CPF group was exposed to 14.5 µg/L CPF for 30 d. 17 miRNAs were differentially expressed in CPF group head kidney tissues according to the results of miRNAome analysis. In addition, histopathological examination and electron microscopy proved that CPF exposure could lead to damage of head kidney and obvious apoptosis characteristics. The possible target genes of miRNA were predicted using online target gene prediction websites, miRNAome sequencing, GO and KEGG enrichment. miRNAome results showed that expression of miR-731 and miR-2188-3p in CPF group was 0.48 time and 0.45 time as control group, respectively. qRT-PCR results proved the reality of miRNAome. During CPF exposure, mRNA expression of TLR pathway genes and its downstream genes involved in autophagy and apoptosis pathway including TLR1, TLR2, TLR7, TLR9, MyD88, IRAK1, IRAK4, IRF7, PI3K, AKT, mTOR, Caspase3, Caspase8 and Bax were differentially increased under CPF exposure, along with ATG13 and Bcl2 decreased at the same time. Western blot results indicated that apoptosis related protein Caspase3 and Caspase8 were differentially up-regulated in the CPF group. In summary, CPF exposure could induce apoptosis while inhibited autophagy in head kidney of common carp via the regulation of miR-2188-3p and miR-731 by targeting TLR pathway. These results provide new insights for unveiling the biological effects of CPF and miRNAs in common carp.

Gross, histological and ultrastructural morphology of the aglomerular kidney in the lined seahorse Hippocampus erectus.

Histologic evaluation of the renal system in the lined seahorse Hippocampus erectus reveals a cranial kidney with low to moderate cellularity, composed of a central dorsal aorta, endothelial lined capillary sinusoids, haematopoietic tissue, fine fibrovascular stroma, ganglia and no nephrons. In comparison, the caudal kidney is moderately to highly cellular with numerous highly convoluted epithelial lined tubules separated by interlacing haematopoietic tissue, no glomeruli, fine fibrovascular stroma, numerous capillary sinusoids, corpuscles of Stannius and clusters of endocrine cells adjacent to large calibre vessels. Ultrastructural evaluation of the renal tubules reveals minimal variability of the tubule epithelium throughout the length of the nephron and the majority of tubules are characterized by epithelial cells with few apical microvilli, elaborate basal membrane infolding, rare electron dense granules and abundant supporting collagenous matrix.

[Ultrastructure of granulocytes of bony fishes (orders Salmoniformes, Cypriniformes, Perciformes)].

Analysis of data on utrastructure of granulocytes of freshwater and marine bony fish of orders Salmoniformes, Cypriniformes, and Perciformes showed that in all studied species there were revealed two types of granulocytes - neutrophils and eosinophils. The exception was the bluefish Pomatomus saltatrix L. whose pronephros hemopoietic tissue was found to contain one type of the granulocytic line - neutrophils. The identification parameters of granular leukocytes are specific granules filling the cytoplasm. The main form of specific granules in neutrophils of bony fish of various phylogenetic groups is an elongated granule with different distribution of fibrils or a granule that has crystalloid formed from fibrils. The main form of eosinophil granules - large, electron-dense, homogenous.

Morphocytochemical, immunohistochemical and ultrastructural characterization of the head kidney of fat snook Centropomus parallelus.

This study characterized the structure and the morphocytochemical, immunohistochemical and ultrastructural aspects of the head kidney (HK) of the fat snook Centropomus parallelus. The HK is enclosed by a thin capsule of connective tissue, from which fine trabeculae originate and branch into the interior of organ. In the parenchyma, there are aggregates of lymphoid cells containing populations of lymphocytes T immunopositive for CDRO45, in a nodular arrangement, around blood vessels and melano-macrophage centres. Among the cells that constituted these aggregates and surrounded them, were macrophages and monocytes, and their precursors, with strong immunopositivity for CD68, along with cells of the granulocytic lineage in various phases of maturation positive for lysozyme and PAS. Macrophages and chromaffin and interrenal cells are also present. Ultrastructurally, the HK comprises a reticulum-endothelial stroma consisting of endothelial cells, reticulocytes of the fibroblast type and macrophage type and a parenchyma with increased cellularity, principally blood cells of the erythrocytic, granulocytic, lymphocytic, monocytic and thrombocytic series.