Interleukin-12 sustained release system promotes hematopoietic recovery after radiation injury.

The continuous production of mature blood cell lineages is maintained by hematopoietic stem cells but they are highly susceptible to damage by ionizing radiation (IR) that induces death. Thus, devising therapeutic strategies that can mitigate hematopoietic toxicity caused by IR would benefit acute radiation syndrome (ARS) victims and patients receiving radiotherapy. Herein, we describe the preparation of an injectable hydrogel formulation based on Arg-Gly-Asp-alginate (RGD-Alg) and Laponite using a simple mixing method that ensured a slow and sustained release of interleukin-12 (IL-12) (RGD-Alg/Laponite@IL-12). The local administration of RGD-Alg/Laponite@IL-12 increased survival rates and promoted the hematopoietic recovery of mice who had received sublethal-dose irradiation. Local intra-bone marrow (intra-BM) injection of RGD-Alg/Laponite@IL-12 hydrogel effectively stimulated IL12 receptor-phosphoinositide 3-kinase/protein kinase B (IL-12R-PI3K/AKT) signaling axis, which promoted proliferation and hematopoietic growth factors secretion of BM mesenchymal stem/stromal cells. This signaling axis facilitates the repair of the hematopoietic microenvironment and plays a pivotal role in hematopoietic reconstitution. In conclusion, we describe a biomaterial-sustained release of IL-12 for the treatment of irradiated hematopoietic injury and provide a new therapeutic strategy for hematopoietic ARS.

Injury and recovery of Escherichia coli ATCC25922 cells treated by high hydrostatic pressure at 400-600 MPa.

Escherichia coli cells were inactivated by high hydrostatic pressure (HHP) at 400-600 MPa and their recovery under various conditions was evaluated by colony counting and flow cytometer (FCM) analyses. The lag time in colony formation and an improved recovery of cells under less oxidative conditions (pyruvate addition to the medium and incubation in anaerobic conditions) were observed for HHP treated cells, which indicated that a significant portion of cells were injured and recovered during incubation after HHP treatment. The lag time for colony formation varied, which suggested a wave of resuscitation and recovered cells may multiply before other injured cells complete resuscitation. The recovery process was monitored by FCM: The FCM profile of cells stained using propidium iodide and SYTO9 indicated that while the majority of cells died just after HHP treatment, the staining pattern of possibly injured cells displayed a specific spectrum that gradually became consistent with that of the dead cell population and a living cell population simultaneously appeared. Pyruvate addition to the medium not only enhanced viability of HHP treated cells, but also reduced the lethal effect of HHP. These observations suggested that the degree of damage by HHP may differ cell-by-cell, and oxidative stress may continue after HHP treatment. Pyruvate addition to the recovery medium enhanced viability of E. coli cells inactivated by HHP treatment in tomato juice as well.

[The role of sub-transform of macrophages in renal ischemia/reperfusion injury in rats].

OBJECTIVE: To investigate the role of sub-transform macrophage in ischemia/reperfusion renal injury in rats, as well as under-lying mechanisms. METHODS: Thirty male Sprague-Dawley rats were randomly divided into ischemia/reperfusion (IRI, n=24, renal artery was occluded for 45 min) group and sham-operation (Sham, n=6) group. The kidneys in IRI group were collected at 0, 6, 24 and 72 h after operation (6 rats for each time point). The injury of the kidney was detected with HE staining. Immunohistochemistry staining was performed to evaluate the expression of proliferating cell nuclear antigen (PCNA). Real-time PCR was used to detect the mRNA expression of macrophage migration inhibitory factor (MIF). Moreover, the expression and location of MIF, monocyte chemoattractant protein-1 (MCP-1) and macrophage marker CD68 were examined by immunofluorescence staining. Most importantly, the distribution of macrophage subtypes M1 and M2 was analyzed by flow cytometry. RESULTS: The worst pathologic damage of the renal tissues, as well as infiltration of inflammatory cells, was observed at 24 h after operation in IRI rats, with obvious recovery afterwards. Immunohistochemistry staining showed that the expression of PCNA was significantly increased after the ischemia/reperfusion, peaking at 6 h and reducing at 72 h after operation. Compared with sham group, the levels of MIF at mRNA and protein levels were both significantly increased after the ischemia/reperfusion, while the expression of MCP-1 was peaked at 6 h and decreased afterwards. Moreover, the expression of CD68-positive macrophages were significantly increased in IRI rats, with peaking at 24 h and reducing at 72 h. Furthermore, after 6 h of reperfusion, the percentage of M1 macrophages reached the peak, and thereafter the relative expression of M1 and M2 was reduced and increased, respectively. CONCLUSIONS: In the early phase of ischemia/per-fu sion renal injury, M1 macrophage results in renal damage, and afterwards the M2 macrophage is increased and repairs the renal damage by improving the cell proliferation.