Enrichment of miR-17-5p enhances the protective effects of EPC-EXs on vascular and skeletal muscle injury in a diabetic hind limb ischemia model

BACKGROUND/AIMS: Diabetes mellitus (DM) is highly susceptible to diabetic hind limb ischemia (DHI). MicroRNA (MiR)-17-5p is downregulated in DM and plays a key role in vascular protection. Endothelial progenitor cell (EPC)-released exosomes (EPC-EXs) contribute to vascular protection and ischemic tissue repair by transferring their contained miRs to target cells. Here, we investigated whether miR-17-5p-enriched EPC-EXs (EPC-EXsmiR-17-5p) had conspicuous effects on protecting vascular and skeletal muscle in DHI in vitro and in vivo. METHODS: EPCs transfected with scrambled control or miR-17-5p mimics were used to generate EPC-EXs and EPC-EXsmiR-17-5p. Db/db mice were subjected to hind limb ischemia. After the surgery, EPC-EXs and EPC-EXsmiR-17-5p were injected into the gastrocnemius muscle of the hind limb once every 7 days for 3 weeks. Blood flow, microvessel density, capillary angiogenesis, gastrocnemius muscle weight, structure integrity, and apoptosis in the hind limb were assessed. Vascular endothelial cells (ECs) and myoblast cells (C2C12 cells) were subjected to hypoxia plus high glucose (HG) and cocultured with EPC-EXs and EPC-EXsmiR-17-5p. A bioinformatics assay was used to analyze the potential target gene of miR-17-5p, the levels of SPRED1, PI3K, phosphorylated Akt, cleaved caspase-9 and cleaved caspase-3 were measured, and a PI3K inhibitor (LY294002) was used for pathway analysis. RESULTS: In the DHI mouse model, miR-17-5p was markedly decreased in hind limb vessels and muscle tissues, and infusion of EPC-EXsmiR-17-5p was more effective than EPC-EXs in increasing miR-17-5p levels, blood flow, microvessel density, and capillary angiogenesis, as well as in promoting muscle weight, force production and structural integrity while reducing apoptosis in gastrocnemius muscle. In Hypoxia plus HG-injured ECs and C2C12 cells, we found that EPC-EXsmiR-17-5p could deliver their carried miR-17-5p into target ECs and C2C12 cells and subsequently downregulate the target protein SPRED1 while increasing the levels of PI3K and phosphorylated Akt. EPC-EXsmiR-17-5p were more effective than EPC-EXs in decreasing apoptosis and necrosis while increasing viability, migration, and tube formation in Hypoxia plus HG-injured ECs and in decreasing apoptosis while increasing viability and myotube formation in C2C12 cells. These effects of EPC-EXsmiR-17-5p could be abolished by a PI3K inhibitor (LY294002). CONCLUSION: Our results suggest that miR-17-5p promotes the beneficial effects of EPC-EXs on DHI by protecting vascular ECs and muscle cell functions.

Effect of Thbs4 gene editing BMSCs transplantation on VEGF and Ang-1 in diabetic hind limb ischemia rats and related mechanism / 国际生物医学工程杂志

Objective To investigate the effects and the mechanism of thrombospondin 4 (Thbs4) gene-edited bone marrow mesenchymal stem cells (BMSCs) transplantation on vascular endothelial growth factor (VEGF) and angiopoietin-1 (Ang-1) in diabetic rats with hind limb ischemia. Methods Thirty Sprague-Dawley rats were randomly divided into the model group, BMSCs treatment group and Thbs4-BMSCs treatment group on average. After constructing the typeⅡdiabetic rat model with hind limb ischemia, 100μl normal saline, BMSCs suspension and Thbs4-BMSCs suspension (cell number: 2×106) were locally injected into the ischemic injury area of rats for the model group, BMSCs group and Thbs4-BMSCs group, respectively. The rats were sacrificed on the 14th day after stem cell transplantation, and the muscle tissues near the ischemic area were collected. The relative expression of VEGF and p-Smad2/3 protein was detected by Western Blot. The Ang-1 protein expression was detected by immunofluorescence staining. The levels of related genes were detected by qRT-PCR, and the von Willebrand Factor (vWF) protein expression was detected by immunohistochemistry staining. Results The relative expression levels of VEGF, Ang-1 and vWF protein in the Thbs4-BMSCs group were significantly higher than those in the model group and BMSCs group (VEGF protein:P<0.01 and P<0.05). The mRNA expression of VEGF and Ang-1 were significantly up-regulated, the differences were statistically significant(VEGF mRNA:all P<0.01;Ang-1:P<0.01 and P<0.05). The expression of p-Smad2/3 protein in the Thbs4-BMSCs group was significantly higher than that in the model group and the BMSCs treatment group (all P<0.01). The expression of p-Smad2/3 protein was significantly decreased after the addition of p-Smad2/3 pathway inhibitor, the differences were statistically significant (P<0.05). Conclusions Thbs4-BMSCs transplantation can effectively promote angiogenesis in diabetic rats with hind limb ischemia, and the effect of angiogenesis may be related to the activation of Smad2/3 signaling pathway.

Acupoint injection of BMSCs combined with Chinese herbs for capillary density in ischemic hind limb of diabetes mellitus rats / 中国针灸

OBJECTIVE@#To observe the effect of acupoint injection of bone mesenchymal stem cells (BMSCs) combined with Chinese herbs of benefiting for activating blood circulation for capillary density and arterioles density in skeletal muscle in ischemic hind limb of diabetes mellitus (DM) rats.@*METHODS@#A total of 80 rats were randomized into a normal sham operation group (10 rats) and a model group (70 rats). Disposable intraperitoneal injection of streptozotocin (STZ, 50.0 mg/kg) was used to establish DM model, and the rats in the model group were randomized into 7 subgroups, 10 rats in each one. The subgroups were the DM sham operation group, DM ischemic group, Chinese herb group (intragastric herbs of benefiting for activating blood circulation), local injection group (BMSCs local injection), local injection + Chinese herb group (BMSCs local injection combined with intragastric herbs of benefiting for activating blood circulation), acupoint injection group (BMSCs acupoint injection), acupoint injection + Chinese herb group (BMSCs acupoint injection combined with intragastric herbs of benefiting for activating blood circulation). The local injection was phosphate buffer (PBS) injection at the equidistant 5 points along the line between the ischemic tissue and the normal tissue a time. The acupoints were "Sanyinjiao" (SP 6), "Zhaohai" (KI 6), "Huantiao" (GB 30), "Housanli" (ST 36) and "Yanglingquan" (GB 34). 100 μL BMSCs with 1×10/mL was totally injected at the above acupoints for one rat, 20 μL an acupoint. 1.5 kg/L Chinese herbs were applied by intragastric administration, including 120 g Radix Astragali, 120 g Codonopsis, 48 g Radix Glycyrrhiza, 120 g Angelica sinensis, 120 g Blood Rattan, 48 g Achyranthes bidentata. Intragastric distilled water was used in the other non-Chinese herb groups. The expressions of α-smooth muscle actin (α-actin), latelet endothelial cell adhesion molecule (CD31) and von willebrand factor (vWF) in the skeletal muscle were detected with immunohistochemical SP two-step method.@*RESULTS@#Twenty-one days after intervention, the expressions of α-actin and CD31 on the operation hind limb were higher than those on the healthy hind limb in all the groups, except the Chinese herb group (<0.05<0.01). The vWF expressions on the operation side were lower than those on the healthy side in the Chinese herb group, the local injection group, the local injection + Chinese herb group and the acupoint injection + Chinese herb group (<0.05, <0.01). The α-actin expression on the operation side in the acupoint injection + Chinese herb group was higher than those in the normal sham operation group, DM sham operation group, the DM ischemic group and the local injection group (<0.05, <0.01). The CD31 expressions in the acupoint injection group, the acupoint injection + Chinese herb group, local injection + Chinese herb group were higher than those in the normal sham operation group, DM sham operation group and DM ischemic group (<0.05, <0.01). The CD31 expression in the acupoint injection + Chinese herb group was higher than those in the Chinese herb group and the local injection group (both <0.05). The vWF expressions in the local injection + Chinese herb group, the acupoint injection group and the acupoint injection + Chinese herb group lower than those in the DM sham operation group and the DM ischemic group (<0.05, <0.01).@*CONCLUSION@#schemia increases the expressions of the vascular density related factors of α-actin and CD31. It is more obvious for the increasing expressions of α-actin and CD31, and decreasing expression of vWF with the interventions of simple BMSCs injection and simple Chinese herbs of benefiting for activating blood circulation, especially with the combination of the above tow methods. It is indicated that acupoint injection of BMSCs combined with Chinese herbs of benefiting for activating blood circulation can improve the angiogenesis of ischemic tissue.

Effect of Naoxintong capsule on endothelial progenitor cell mobilization and homing following bone marrow transplantation in a mouse hind limb ischemia model / 中国中药杂志

Endothelial progenitor cells (EPCs) are precursor cells of endothelial cells. Signal molecules produced by ischemia and hypoxia can promote mobilization of bone marrow EPCs to peripheral circulation and formation of novel blood vessels in tissues that are damaged during heart attack. Naoxintong capsule (NXT) has the functions of promoting blood circulation, removing blood stasis, promoting the circulation of qi and relieving pain. The various components in NXT have protective effects on blood vessels and can effectively improve the symptoms of ischemia. However, its effect on EPCs is not clear. To study the intervention effect of NXT on mobilization and homing of peripheral blood EPCs, green fluorescent protein (GFP) transgenic mice were used for bone marrow transplantation (BMT) and then unilateral hind limb ischemia model (UHLI) were constructed. For BMT, wild-type ICR mice were irradiated by CS137 and then injected with 4×106 bone marrow cells isolated from GFP mice. The bone marrow reconstitution of recipients was assessed by quantification of GFP bone marrow-derived cells (BMDC) from transplanted mice 4 weeks after BMT. The UHLI model was duplicated by ligating femoral artery and divided into three groups: the model group, the NXT group (model+NXT) and the positive control group (model+simvastatin). Flow cytometry was used to detect the proportion of GFP positive cells and the peripheral blood EPCs levels at 1, 3, 7, 14 days before and after surgery. Ischemic tissue of gastrocnemius muscle was excised at 3 and 7 days after operation for immunofluorescence staining to detect the number of GFP+ cells. The bone marrow chimerism was achieved at day 28 after BMT. There was no significant difference in the percentage of GFP positive cells between BMT mice and GFP transgenic mice. NXT and simvastatin could significantly increase the number of peripheral blood EPCs 1,3 days after surgery. Three and seven days after operation, the number of homing EPCs was significantly higher in NXT group and positive control group than that in model group (P<0.001). In conclusion, NXT can obviously promote the mobilization and homing of EPCs.

The relationship between hind limb ischemia of diabetic rats and endothelial nitric oxide synthase uncoupling / 中华内分泌外科杂志

Objective To investigate the relationship between vascular injury of diabetic rats with hind limb ischemia and endothelial nitric oxide synthase(eNOS) uncoupling.Methods 15 SD rats were randomly divided into 3 groups:control group (n =5),diabetes group (n =5) and diabetes ischemia group (n =5).Two weeks after the diabetic rat model and hind limb ischemia of diabetic rat model were set up,Enzyme linked immunosorbent assay(ELISA) was used to detect nitric oxide(NO) expression in the rat femoral artery; Dihydroethidium(DHE) fluorescent probe was used to detect superoxide(O2-) production in the frozen section of femoral artery; and Western blot was used to examine GTP cyclohydrolase 1 (GTPCH-1)expression in femoral artery.Results ①Compared with the control group,NO expression of femoral artery in diabetes group was significantly reduced,diabetes ischemia group decreased more significantly,and the difference between the 3 groups had statistical significance(P =0.000,P =0.000,P =0.001).②Frozen section showed:compared with the control group,O2-expression of diabetes group significantly increased,but not as much as diabetes hind limb ischemia group.③Western blot results showed that compared with the control group,the expression of GTPCH-1 in diabetes group reduced,diabetes hind limb ischemia group decreased more significantly,and the difference between the 3 groups had statistical significance (P =0.001,P =0.000,P =0.012).Conclusion eNOS uncoupling is present in diabetic rats with hind limb ischemia and vascular injury.

Change in blood flow of rats with diabetes mellitus after the acute hind limb ischemia / 基础医学与临床

Objective To establish the acute hind limb ischemia on Wistar rat with diabetes mellitus.MethodsThirty diabetes rats were induced by intraperitoneal STZ (50 mg/kg) injection, as well as the blood glucose level tested over 16.8 mmol/L. The rats were ligated on the left femoral artery, then the blood perfusion on the hind limbs ischemia was measured by LDPI after the operation. Results The fasting plasma glucose level on 22 Wistar rats(81.5%) was kept above 16.8 mmol/L, and the hind limb blood perfusion would recover slowly to the level of the right side from 1 to 14 day (P

Assessment of microcirculation in a hind limb ischemia model / 中国药理学通报

Aim To establish the standards for evaluation of microcirculation in a rat hind limb ischemia model.Methods Rats were subjected to unilateral femoral artery ligation.After 4 weeks,the regional blood flow in skeletal muscles was measured by fluorescent microsphere assay.Formation of collateral vessels was determined by microangiography.Capillary density was examined by immunostaining for CD34.Results In ischemic limbs,regional blood flow decreased significantly,some collateral vessels formed with typical "corkscrew" appearance,and histological analysis showed lower capillary density.Conclusion Quantitative assessment of microcirculation in a hind limb ischemia model is established.