Mussel inspired 3D elastomer enabled rapid calvarial bone regeneration through recruiting more osteoprogenitors from the dura mater.

Currently, the successful healing of critical-sized calvarial bone defects remains a considerable challenge. The immune response plays a key role in regulating bone regeneration after material grafting. Previous studies mainly focused on the relationship between macrophages and bone marrow mesenchymal stem cells (BMSCs), while dural cells were recently found to play a vital role in the calvarial bone healing. In this study, a series of 3D elastomers with different proportions of polycaprolactone (PCL) and poly(glycerol sebacate) (PGS) were fabricated, which were further supplemented with polydopamine (PDA) coating. The physicochemical properties of the PCL/PGS and PCL/PGS/PDA grafts were measured, and then they were implanted as filling materials for 8 mm calvarial bone defects. The results showed that a matched and effective PDA interface formed on a well-proportioned elastomer, which effectively modulated the polarization of M2 macrophages and promoted the recruitment of dural cells to achieve full-thickness bone repair through both intramembranous and endochondral ossification. Single-cell RNA sequencing analysis revealed the predominance of dural cells during bone healing and their close relationship with macrophages. The findings illustrated that the crosstalk between dural cells and macrophages determined the vertical full-thickness bone repair for the first time, which may be the new target for designing bone grafts for calvarial bone healing.

A 3D-Printed Cuttlefish Bone Elastomeric Sponge Rapidly Controlling Noncompressible Hemorrhage.

Developing a self-expanding hemostatic sponge with high blood absorption and rapid shape recovery for noncompressible hemorrhage remains a challenge. In this study, a 3D-printed cuttlefish bone elastomeric sponge (CBES) is fabricated, which combined ordered channels and porous structures, presented tunable mechanical strength, and shape memory potentials. The incorporation of cuttlefish bone powder (CBp) plays key roles in concentrating blood components, promoting aggregation of red blood cells and platelets, and activating platelets, which makes CBES show enhanced hemostatic performance compared with commercial gelatin sponges in vivo. Moreover, CBES promotes more histiocytic infiltration and neovascularization in the early stage of degradation than gelatin sponges, which is conducive to the regeneration and repair of injured tissue. To conclude, CBp loaded 3D-printed elastomeric sponges can promote coagulation, present the potential to guide tissue healing, and broaden the hemostatic application of traditional Chinese medicine.

Isoflurane-induced reduction in neurogenesis derived from the tertiary dentate matrix.

Anesthetics-induced disruption of dentate neurogenesis in the young brain is strongly suggested to contribute to delayed neurocognitive deficit. In postnatal rodents, the neurogenesis of the dentate gyrus (DG) is sequentially derived from the secondary dentate matrix, tertiary dentate matrix and subgranular zone (SGZ). However, the effects of anesthetics on the dentate neurogenesis derived from specific sites are poorly understood. To trace the new cells generated from the postnatal secondary dentate matrix, peak stage of the tertiary dentate matrix and early stage of the SGZ after isoflurane exposure, mice at postnatal day 1 (P1), P7 and P31 were injected with BrdU at 12 h before the exposure. We found that isoflurane exposure significantly reduced the numbers of proliferating cells (1 day old), immature granule cells (21 days old) or mature granule cells (42 days old) derived from the peak stage of the tertiary dentate matrix and postnatal secondary dentate matrix, but not from the SGZ. Quantitative assessment of BrdU-/BrdU+NeuN-positive cells and cleaved caspase-3 level in the DG indicated that the reduction was correlated with cell loss rather than neuronal differentiation. Mechanistically, we demonstrated that the PI3K/Akt/GSK-3ß pathway enriched by mRNA-sequencing is a requirement for the isoflurane-induced loss of 1-day-old proliferating cells generated from the tertiary dentate matrix. In addition, this study demonstrated that P1 and P7 mice, but not P31 mice exposure to isoflurane resulted in subsequent deficits in performance of the tasks of the Morris Water Maze.

Nephropathy and hepatopathy in weaned piglets provoked by natural ochratoxin A and involved mechanisms.

Ochratoxin A (OTA) contamination is a worldwide problem in pig industry. The objectives of the present study were to investigate the toxicity of natural OTA in weaned piglets and to further explore the underlying mechanisms. Totally, 36 crossbred ([Landrace × Yorkshire] × Duroc) piglets were randomly divided into 3 groups (three replicates per group, 4 piglets per replicate), and fed a basal diet (Con group) and basal diets added with 0.4 mg (OTA-L group) or 0.8 mg OTA/kg (OTA-H group), respectively for 42 days. The results showed that growth performance was significantly decreased (P<0.05) in OTA added groups compared with Con group. OTA concentration was relatively high in serum and OTA concentration in kidney was higher than in liver, respectively. AST, creatinine and urea in serum of OTA added groups were significantly increased (P<0.05), while glucose, total protein, albumin and globulin in serum of OTA added groups were significantly decreased (P<0.05) compared with Con group. Degenerative changes were observed in the epithelial cells of proximal tubules and in hepatocytes of OTA added groups. Antioxidant capacities in blood of OTA added groups and in kidney of OTA-H group were significantly decreased (P<0.05) compared with Con group. The mRNA expressions of bcl-2 were up-regulated, mRNA expressions of bax were down-regulated and the ratio of bcl-2 and bax was increased in kidney and liver of OTA added groups compared with Con group. In conclusion, OTA could reduce antioxidant capacity and suppress apoptosis in tissues and cause degenerative changes in the epithelial cells in proximal tubules and hepatic cells, which may have a negative effect on the growth performance of piglets.

Astragalus polysaccharides inhibits PCV2 replication by inhibiting oxidative stress and blocking NF-κB pathway.

Porcine circovirus type 2 (PCV2) is the primary causative agent of porcine circovirus-associated disease (PCVAD). Astragalus polysaccharide (APS), as one kind of biological macromolecule extracted from Astragalus, has antiviral activities. This study was undertaken to explore the effect of APS on PCV2 replication in vitro and the underlying mechanisms. Our results showed that adding APS before PCV2 infection decreased significantly PCV2 DNA copies, the number of infected cells, MDA level, ROS level and NF-κB activation in PK15 cells and increased significantly GSH contents and SOD activity compared to control without APS. Oxidative stress induced by BSO could eliminate the effect of PCV2 replication inhibition by APS. LPS, as a NF-κB activator, could attenuate the effect of PCV2 replication inhibition by APS. BAY 11-7082, as a NF-κB inhibitor, could increase the effect of PCV2 replication inhibition by APS. In conclusion, APS inhibits PCV2 replication by decreasing oxidative stress and the activation of NF-κB signaling pathway, which suggests that APS might be employed for the prevention of PCV2 infection.

Ochratoxin A promotes porcine circovirus type 2 replication in vitro and in vivo.

Ochratoxin A (OTA), a worldwide mycotoxin found in food and feeds, is a potent nephrotoxin in animals and humans. Porcine circovirus-associated disease (PCVAD), including porcine dermatitis and nephropathy syndrome, is a worldwide swine disease. To date, little is known concerning the relationship between OTA and porcine circovirus type 2 (PCV2), the primary causative agent of PCVAD. The effects of OTA on PCV2 replication and their mechanisms were investigated in vitro and in vivo. The results in vitro showed that low doses of OTA significantly increased PCV2 DNA copies and the number of infected cells. Maximum effects were observed at 0.05 µg/ml OTA. The results in vivo showed that PCV2 replication was significantly increased in serum and tissues of pigs fed 75 µg/kg OTA compared with the control group and pigs fed 150 µg/kg OTA. In addition, low doses of OTA significantly depleted reduced glutathione and mRNA expression of NF-E2-related factor 2 and γ-glutamylcysteine synthetase; increased reactive oxygen species, oxidants, and malondialdehyde; and induced p38 and ERK1/2 phosphorylation in PK15 cells. Adding N-acetyl-L-cysteine reversed the changes induced by OTA. Knockdown of p38 and ERK1/2 by their respective specific siRNAs or inhibition of p38 and ERK1/2 phosphorylation by their respective inhibitors (SB203580 and U0126) eliminated the increase in PCV2 replication induced by OTA. These data indicate that low doses of OTA promoted PCV2 replication in vitro and in vivo via the oxidative stress-mediated p38/ERK1/2 MAPK signaling pathway. This suggests that low doses of OTA are potentially harmful to animals, as they enhance virus replication, and partly explains why the morbidity and severity of PCVAD vary significantly in different pig farms.