The effectiveness of early local administration of hyaluronic acid in experimental traumatic ischemia of the limb muscles

The experiments were performed on 280 male Wistar rats weighing 300-340 g. The design of the study included: modeling of compression injury of the soft tissues of the thigh, local injection of the preparation of hyaluronic acid "Gialift 3.5" into the area of damage 3 hours after the cessation of compression, taking into account the results after 7, 14 and 28 days. The introduction of hyaluronic acid into the area of compression injury of soft tissues reduces the severity of myoglobinemia, increases the immunohistochemical density of VEGF-positive cells, improves the perfusion characteristics of microcirculation, oxygen saturation, and specific oxygen consumption by tissues. Keywords: traumatic muscle ischemia, hyaluronic acid, myoglobin, microcirculation, metabolism, laser Doppler flowmetry, morphometry.

The Absence of Extracellular Cold-Inducible RNA-Binding Protein (eCIRP) Promotes Pro-Angiogenic Microenvironmental Conditions and Angiogenesis in Muscle Tissue Ischemia

Extracellular Cold-inducible RNA-binding protein (eCIRP), a damage-associated molecular pattern, is released from cells upon hypoxia and cold-stress. The overall absence of extra- and intracellular CIRP is associated with increased angiogenesis, most likely induced through influencing leukocyte accumulation. The aim of the present study was to specifically characterize the role of eCIRP in ischemia-induced angiogenesis together with the associated leukocyte recruitment. For analyzing eCIRPs impact, we induced muscle ischemia via femoral artery ligation (FAL) in mice in the presence or absence of an anti-CIRP antibody and isolated the gastrocnemius muscle for immunohistological analyses. Upon eCIRP-depletion, mice showed increased capillary/muscle fiber ratio and numbers of proliferating endothelial cells (CD31+/CD45−/BrdU+). This was accompanied by a reduction of total leukocyte count (CD45+), neutrophils (MPO+), neutrophil extracellular traps (NETs) (MPO+CitH3+), apoptotic area (ascertained via TUNEL assay), and pro-inflammatory M1-like polarized macrophages (CD68+/MRC1−) in ischemic muscle tissue. Conversely, the number of regenerative M2-like polarized macrophages (CD68+/MRC1+) was elevated. Altogether, we observed that eCIRP depletion similarly affected angiogenesis and leukocyte recruitment as described for the overall absence of CIRP. Thus, we propose that eCIRP is mainly responsible for modulating angiogenesis via promoting pro-angiogenic microenvironmental conditions in muscle ischemia.

Differential Regulation of Damage-Associated Molecular Pattern Release in a Mouse Model of Skeletal Muscle Ischemia/Reperfusion Injury

BackgroundSkeletal muscle ischemia/reperfusion (I/R) injury is an important clinical issue that can cause remote organ injury. Although its pathogenesis has not been fully elucidated, recent studies have suggested that damage-associated molecular patterns (DAMPs) are mediators of remote organ injury in sterile inflammation. The purpose of this study was to investigate the possible involvement of DAMPs, including the nuclear proteins high-mobility group box 1 (HMGB1) and histone H3, in the pathogenesis of skeletal muscle I/R injury in mice.MethodsHindlimb ischemia was induced in mice through bilateral ligation of inguinal regions using rubber grommets. Reperfusion was induced by cutting the rubber grommets after 2–12 h of ischemic period. Survival rates, localization of HMGB1 and histone H3 in the gastrocnemius muscle, and circulating HMGB1 and histone H3 levels were analyzed. The effect of anti-HMGB1 and anti-histone H3 antibodies on survival was analyzed in mice with I/R injury.ResultsAll mice with hindlimb ischemia survived for at least 36 h, while all mice died within 24 h if the hindlimbs were reperfused after ischemia for 4–12 h. Immunohistochemical analysis revealed that HMGB1 translocated from the nucleus to the cytoplasm in the ischemic gastrocnemius muscle, while histone H3 was confined to the nucleus. Accordingly, serum HMGB1 levels were significantly elevated in mice with hindlimb I/R compared with normal mice or mice with hindlimb ischemia (P < 0.05). Serum histone H3 levels were not elevated after I/R. Treatment with anti-HMGB1 antibodies significantly improved survival of mice with hindlimb I/R injury compared with control antibodies (P < 0.05).ConclusionsHMGB1, but not histone H3, translocated to the cytoplasm during skeletal muscle ischemia, and was released into the systemic circulation after reperfusion in mice with I/R injury. Treatment with anti-HMGB1 antibodies partially improved survival.

Lycopene hampers lung injury due to skeletal muscle ischemia-reperfusion in rat model

This study investigates lycopene’s preventive efficacy in skeletal muscle ischemia-reperfusion (I/R) induced lung injury. Thirty-two rats were randomly assigned to control group, lycopene group, I/R group and I/R + lycopene group. In the lycopene and I/R + lycopene groups, the rats initially received 10 mg/kg/day lycopene orally for 15 days. Then, dissection around the abdominal aorta was performed in all rats under general anesthesia. The aorta was clamped at the infrarenal level in the I/R group and I/R + lycopene group for two hours before two hours of reperfusion. The mean serum levels of malondialdehyde (53.0 ± 20.14 nmol/mL) and superoxide dismutase (1.03 ± 0.16 U/mL) were higher and lower in the I/R group than the other three groups, respectively (p < 0.001). The mean serum IMA level of I/R + lycopene group (0.42 ± 0.04 abs/u) was lower than the I/R group (0.47 ± 0.04 abs/u) (p = 0.015). The mean tissue malondialdehyde levels of I/R group (69.10 ± 11.55 nmol/mL) and I/R + lycopene group (68.36 ± 21.17 nmol/mL) were high compared to the control group (49.87 ± 6.52 nmol/mL) and lycopene group (47.82 ± 4.44 nmol/mL) (p = 0.002). The mean tissue glutathione peroxidase (p < 0.001) and superoxide dismutase (p = 0.001) levels of I/R group (121.81 ± 43.59 nmol/mL and 25.17 ± 8.69 U/mL) were low compared to the control group (236.12 ± 18.01 nmol/mL and 46.30 ± 5.17 U/mL), lycopene group (227.52 ± 16.92 nmol/mL and 45.82 ± 4.02 U/mL), and I/R + lycopene group (176.02 ± 24.27 nmol/mL and 35.20 ± 4.85 U/mL). The histopathological analyses of I/R + lycopene group indicated less significant changes than the control group. Tissue damage in the I/R + lycopene group was less prominent than the I/R group. These findings suggest oral lycopene supplementation as a promising prevention against skeletal muscle I/R caused lung injury.