Bone marrow mesenchymal stem cells repair spinal cord ischemia/reperfusion injury by promoting axonal growth and anti-autophagy

Bone marrow mesenchymal stem cells can differentiate into neurons and astrocytes after trans- plantation in the spinal cord of rats with ischemia/reperfusion injury. Although bone marrow mesenchymal stem cells are known to protect against spinal cord ischemia/reperfusion injury through anti-apoptotic effects, the precise mechanisms remain unclear. In the present study, bone marrow mesenchymal stem cells were cultured and proliferated, then transplanted into rats with ischemia/reperfusion injury via retro-orbital injection. Immunohistochemistry and immunofluorescence with subsequent quantification revealed that the expression of the axonal regeneration marker, growth associated protein-43, and the neuronal marker, microtubule-as- sociated protein 2, significantly increased in rats with bone marrow mesenchymal stem cell transplantation compared with those in rats with spinal cord ischemia/reperfusion injury. Fur- thermore, the expression of the autophagy marker, microtubule-associated protein light chain 3B, and Beclin 1, was significantly reduced in rats with the bone marrow mesenchymal stem cell transplantation compared with those in rats with spinal cord ischemia/reperfusion injury. Western blot analysis showed that the expression of growth associated protein-43 and neuro- filament-H increased but light chain 3B and Beclin 1 decreased in rats with the bone marrow mesenchymal stem cell transplantation. Our results therefore suggest that bone marrow mes- enchymal stem cell transplantation promotes neurite growth and regeneration and prevents autophagy. These responses may likely be mechanisms underlying the protective effect of bone marrow mesenchymal stem cells against spinal cord ischemia/reperfusion injury.

Cardioprotective effects of Salvia miltiorrhiza Bunge and Lignum dalbergiae odoriferae on rat myocardial ischemia/reperfusion injury

Aim Salvia miltiorrhiza Bunge （SM） and lignum dalbergiae odoriferae （DO） are both traditional Chi- nese medicine that have cardioprotective effects. Here, we further examined the combined effects of SM and DO on rat myocardial ischemia/reperfusion injury. The possible mechanism of SM and DO also were elucidated. Methods DO was divided into aqueous extract of lignum dalbergiae odoriferae （DOW） and lignum dalbergiae odoriferae oil （DOO）. Sprague-Dawley rats were randomized to seven groups： sham group, model group, treatment groups inclu- ding SM （10 g · kg^-1）, DOW （5 g · kg^-1）, DOO （0.5 ml · kg^-1）, SM ＋ DOW （10 g · kg^-1 ＋ 5 g · kg^-1）, SM ＋ DOO （ 10 g · kg^-1 ＋ 0. 5 ml · kg^-1）. Rats were pretreated with homologous drug for 7 days and then subjec- ted to 30 rain of ischemia followed by 180 rain of reperfusion. Electrocardiogram （ECG） and heart rate were moni- tored and recorded continuously. At the end of reperfusion, blood samples were collected to determine the serum levels of creatine kinase-MB （CK-MB） and lactate dehydrogenase （LDH）. Hearts were harvested to assess heart- body rate, infarct size and histopathological changes as well. Maximum and minimum effective points were deter- mined by measuring indicators associate with myocardial injury at different time-points of reperfusion （Smin, 15min, 30min, 45rain, 60min, 120min, 180min）. The potential therapeutic mechanism of SM and SM ＋ DOO were carried out by detecting superoxide dismutase （SOD）, malondialdehyde （MDA）, tumor necrosis factor-alpha （TNF-alpha） and interleukin 6 （IL-6）. Results The results showed SM and DO can ameliorate cardiac function respectively, and this cardioprotective effect was further strengthened by their combinations. Among all the combi- nations, SM ＋ DOO showed predominant potential to improve ECG and heart rate, reduce heart-body rate （28.5% ＋ 1.4% , P 〈 0.01 vs model） and myocardial infarct size （ 20.96% ＋ 1.61% , P 〈 0.01 vs model, P 〈 0.05 vs SM） , attenuate histopathological damage, decrease the levels of CK-MB and LDH （P 〈 0.01 vs model, P 〈 0.05 vs SM）. The maximum effective points of SM and SM ＋ DOO were 15min and 30rain respectively, and the minimum effective points of them were 180rain. In reducing serum level of MDA, TNF-alpha, IL-6 and increasing SOD activ- ity, SM ＋ DOO was similar to SM. Conclusion The results of this study indicated that SM ＋ DOO have combined effects that are highly effective than single pretreatment against myocardial ischemie reperfusion injury in rats. The possible mechanism of SM and DO were likely through its anti-oxidant and anti-inflammatory properties, and thus may be an effective and promising medicine for both prophylaxis and treatment of ischemic heart disease.

TNF-α and plasma D(-)-lactate levels in rats after intestinal ischemia and reperfusion

Objective To study the potential role of tumor necrosis factor-α (TNF-α) induction in the development of mucosal barrier dysfunction in rats caused by acute intestinal ischemia-reperfusion injury, and to examine whether pretreatment with monoclonal antibody against TNF-α (TNF-α MoAb) would affect the release of D(-)-lactate after local gut ischemia followed by reperfusion. Methods Anesthetized Sprague-Dawley rats underwent superior mesenteric artery occlusion for 75 min followed by reperfusion for 6 hr. The rats were treated intravenously with either TNF-α MoAb (20 mg/kg) or albumin (20 mg/kg) 30 min prior to the onset of ischemia. Plasma D(-)-lactate levels were measured in both the portal and systemic blood by an enzymatic spectrophotometric assay. Intestinal TNF-αmRNA expression as well as protein levels were also measured at various intervals. In addition, a postmortem examination was performed together with a macropathological evaluation based on a four-grade scoring system.Results Intestinal ischemia resulted in a significant elevation in D(-)-lactate levels in the portal vein blood in both the control and treatment groups ( P ＜0.05). However, animals pretreated with TNF-α MoAb at 6 hr after reperfusion showed significant attenuation of an increase in both portal and systemic D(-)-lactate levels when compared with those only receiving albumin (P ＜ 0.05). In the control animals, a remarkable rise in intestinal TNF-α level was measured at 0.5 hr after clamp release ( P ＜ 0.01); however, prophylactic treatment with TNF-α MoAb completely annulled the increase of local TNF-α levels seen in the control animals. Similarly, after anti-TNF-α MoAb administration, intestinal TNF-α mRNA expression was markedly inhibited, which showed significant differences when compared with the control group at 0.5 hr, 2 hr and 6 hr after the release of occlusion ( P ＜ 0.05-0.01 ). In addition, the pathological examination showed marked intestinal lesions that formed during ischemia, which were much worse upon reperfusion,particularly at the 6 hr time point. These acute injuries were obviously attenuated in animals receiving TNF-α MoAb.Conclusions It appeared that acute intestinal ischemia was associated with failure of the mucosal barrier, resulting in increased plasma D(-)-lactate levels in both portal and systemic blood. These results suggest that TNF-α appears to be involved in the development of local damage associated with intestinal ischemic injury. Moreover, prophylactic treatment with TNF-α MoAb exerts preventive effects on ischemia/ reperfusion-induced circulating D (-)-lactate elevation and gut injury. ( J Geriatr Cardiol 2004;1(2):119-124. )

Protection of carbon monoxide-releasing molecule against lung injury induced by limb ischemia-reperfusion

Objective： To observe the role and mechanism of CO- releasing molecule （CORM）-2 in lung injury induced by ischemia-reperfusion （IR） of hind limbs in rats. Methods： Arat model of lung injury induced by IR of hind limbs was established. A total of 40 Sprague Dawley （SD） rats were randomly divided into 5 groups （n = 8）： sham, sham ＋ CORM-2, IR, IR ＋ CORM-2 and IR ＋ dimethyl sulfoxide （DMSO）. Rats in the IR group received hind limb ischemia for 2 hours and reperfusion for 2 hours, rats in the sham group underwent sham surgery without infrarenal aorta occlusion, rats in the IR＋CORM-2 group and in the sham ＋ CORM-2 group were given CORM-2 （10 μmol/kg intravenous bolus） 5 minutes before reperfusion or at the corresponding time points, while rats in the IR ＋ DMSO group was treated with the same dose of vehicle （DMSO） at the same time. The lung tissue structure, polymorphonuclear neutrophil （PMN） count, wet-to-dry weight ratio （W/D）, malondialdehyde （MDA） content, myeloperoxidase （MPO） activity, intercellular adhesion molecule- 1 （ICAM- 1）expression, I κBα degradation and nuclear factor （NF）-κB activity in the lungs were assessed. Results： As compared with the sham group, lung PMNs number, W/D, MDA content, MPO activity, ICAM-1 expression and NF- κB activity significantly increased in the IR group, but the level of I κBα decresed （P〈0.01）. Compared with the IR group, lung PMNs number, W/D, MDA content, MPO activity and ICAM- 1 expression significantly decreased in the IR＋COMR-2 group （P〈0.01）, while the level of IκBα increased. Conclusions： These data demonstrate that CORM-2 attenuates limb IR-induced lung injury through inhibiting ICAM-1 protein expression, NF-κB pathway and the leu- kocytes sequestration in the lungs following limb IR in rats, suggesting that CORM-2 may be used as a therapeutic agent against lung injury induced by limb IR.