Effects of Kupffer cell inactivation on graft survival and liver regeneration after partial liver transplantation in rats.

BACKGROUND: Gadolinium chloride (GdCl3) selectively inactivates Kupffer cells and protects against ischemia/reperfusion and endotoxin injury. However, the effect of Kupffer cell inactivation on liver regeneration after partial liver transplantation (PLTx) is not clear. This study was to investigate the role of GdCl3 pretreatment in graft function after PLTx, and to explore the potential mechanism involved in this process. METHODS: PLTx (30% partial liver transplantation) was performed using Kamada's cuff technique, without hepatic artery reconstruction. Rats were randomly divided into the control low-dose (5 mg/kg) and high-dose (10 mg/kg) GdCl3 groups. Liver injury was determined by the plasma levels of alanine aminotransferase and aspartate aminotransferase, liver regeneration by PCNA staining and BrdU uptake, apoptosis by TUNEL assay. IL-6 and p-STAT3 levels were measured by ELISA and Western blotting. RESULTS: GdCl3 depleted Kupffer cells and decreased animal survival rates, but did not significantly affect alanine aminotransferase and aspartate aminotransferase (P>0.05). GdCl3 pretreatment induced apoptosis and inhibited IL-6 overexpression and STAT3 phosphorylation after PLTx in graft tissues. CONCLUSION: Kupffer cells may contribute to the liver regeneration after PLTx through inhibition of apoptosis and activation of the IL-6/p-STAT3 signal pathway.

Panaxynol ameliorates cardiac ischemia/reperfusion injury by suppressing NLRP3-induced pyroptosis and apoptosis via HMGB1/TLR4/NF-κB axis.

BACKGROUND AND PURPOSE: Panaxynol (PNN) is a common natural minor component in Umbelliferae plants. Many clinical studies have shown that PNN exhibits nutritional value and anti-inflammatory and other pharmacological activities. However, whether PNN can mediate cardiac ischemia/reperfusion injury (IRI) remains unclear. Here, we aimed to determine the potential effects of PNN on myocardial IRI. METHODS: Myocardial IRI was stimulated in a mouse IRI model, and neonatal rat ventricle myocytes (NRVMs) were exposed to hypoxia/reoxygenation to construct in an vitro model. Myocardial infarction size, myocardial tissue injury, myocardial apoptotic index, hemodynamic monitoring, pyroptosis-related proteins, cardiac enzyme activities and inflammatory responses were examined to assess myocardial injury. RESULTS: It was found that PNN administration markedly reduced myocardial infarct size and apoptosis, suppressed myocardial damage and cell pyroptosis, attenuated pro-inflammatory cytokines and neutrophil infiltration via NLRP3 inhibitor. More importantly, PNN treatment remarkably decreased the expression of TLR4/NF-κB pathway-associated proteins and NLRP3-related pyroptosis proteins by HMGB1 inhibitor. PNN also enhanced cell viability, reduced cardiac enzyme activities, suppressed apoptosis and attenuated inflammation in the isolated NRVMs. Furthermore, vitro studies indicated that MCC950 (a NLRP3 inhibitor) increased the anti-inflammatory and anti-apoptotic effects of PNN on NRVMs via HMGB1/TLR4 pathway. CONCLUSION: To sum up, our results demonstrate that PNN exhibits a cardioprotective effect by modulating heart IRI-induced apoptosis and pyroptosis via HMGB1/TLR4/NF-κB pathway, thereby inhibiting NLRP3 inflammasome stimulation.

Effects of the nerve growth factor on the survival and wound healing in mice with combined radiation and wound injury.

High dose of ionizing radiation could cause bone-marrow aplasia and delay wound healing. Nerve growth factor (NGF) has been demonstrated to play roles in wound healing and to affect the functional activities of mature immune and hematopoietic cells. In this study, we investigated the effects of NGF on survival and wound healing in mice with combined radiation and wound injury. Immunohistochemical analysis indicated that the expression of NGF decreased significantly at postwounding days 3, 5, 7, 10 and 14 in wounded tissues combined with total body irradiation of 5 Gy. NGF significantly increased the survival and migration of skin fibroblasts with the irradiation of 15 Gy in in vitro experiments. Intraperitoneal and topical applications of NGF increased the survival rate, peripheral white blood cells and bone-marrow nucleated cells; they also promoted wound healing and increased the cell number of fibroblasts and blood capillaries in granulation tissues. These results showed evidence that NGF could increase wound healing and promote survival in irradiated animals. This dual effect of NGF may provide a new tool for the treatment of radiation-combined injuries.

Transplantation of dermal multipotent cells promotes the hematopoietic recovery in sublethally irradiated rats.

Our previous study indicated that dermal multipotent cells with the differentiation capacity to form cells with the phenotypic properties of osteocytes, adipocytes, chondrocytes, and neurons in specific inducing media could be isolated from the enzymatically dissociated dermal cells of newborn rats by their adherence to culture dish plastic. We have also observed that the systemic transplantation of dermal multipotent cells could not repopulate the hematopoietic system in lethally irradiated rats. In this paper, we found that a transplantation of plastic-adherent dermal multipotent cells into sublethally irradiated rats led to a significant increase of white blood cells in peripheral blood, nucleated cells, CFU-GM, and CFU-F colonies in bone marrow. FISH analysis, using a Y-chromosome specific probe, showed that dermal multipotent cells could engraft into bone marrow in recipients. Flow cytometry (FACS) analysis also showed that the proportion of CD2 and CD25 positive lymphocytes in peripheral blood did not change significantly in two weeks after transplantation. By these results, we infer that dermal multipotent cells may represent an alternative origin of mesenchymal stem cells to restore marrow microenvironment and promote the survival, engraftment, and proliferation of hematopoietic cells.

[Effects of total body irradiation injury on the participation of dermal fibroblasts in tissue repair].

Wound combined with total body irradiation (TBI) injury results in impairment of tissue repair and delayed processes of healing, so it has been considered as an important and representative model of impaired wound healing, but the mechanism is not fully clarified. Fibroblasts in wound are the most important cells participating in tissue repair, whereas its radiosensitivity is not high. To understand whether TBI injury has direct damaging effects on fibroblasts in wound, fibroblasts in wound combined with TBI injury and in wound of simple incision injury were isolated and cultured, and parameters associated with tissue repair were determined. The results showed that the abilities of proliferation, attachment and adhesion of fibroblasts isolated from wounds combined with TBI injury significantly decreased as compared with those of simple incision injury, nevertheless, apoptotic ratio of fibroblasts isolated from wounds combined with TBI injury increased significantly. These data suggest that TBI injury may cause direct damaging effects on fibroblasts in wounds, which might be one of the dominant reasons for impairment of wound healing when it is combined with TBI injury.