Expression and significance of hypoxia-inducible factor-1α and vascular endothelial growth factor and receptor 2 in stage 3 pressure injury of rats / 中国应用生理学杂志

OBJECTIVE@#To analyze the expression and relationship of hypoxia-inducible factor-1α (HIF-1α), vascular endothelial growth factor (VEGF) and kinase insert domain receptor (KDR) in local skin tissues of pressure injury and investigate the possible mechanism of stage 3 pressure injury refractory wound.@*METHODS@#Forty male SD rats were randomly divided into normal control group, compressed 3 d, 5 d, 7 d, and 9 d groups. Stage 3 pressure injury animal model were established by magnet compression. The morphology of skin was observed by HE staining. The expression of VEGF was detected by immunohistochemistry. The expression levels of HIF-1α, VEGF and KDR protein in skin tissue were detected by Western blot. One-way analysis of variance and LSD test were performed on the data.@*RESULTS@#①The HE results showed that compared with the normal control group, the epidermis of the compressed group was gradually thickened, the number of blood vessels was decreased, the collagen arrangement disordered and inflammatory cells infiltration were increased. ②Immunohistochemical results showed that the expression of VEGF protein in the 3 d group was significantly higher than that in the normal control group (P＜0.01). The expression of VEGF protein in the skin tissue of 5 d, 7 d and 9 d groups was lower than that in normal control group (P＜0.05). WB results were consistent with immunohistochemistry results. ③WB results showed that the expression of HIF-1α in the skin tissues of the rats in 3 d, 5 d and 7 d groups was higher than that in the normal control group (P＜0.01 or P＜0.05). The expression of KDR protein was lower than that of the normal control group (P＜0.05 or P＜0.01).@*CONCLUSION@#HIF-1α mediated reduction of VEGF and KDR protein expression and decreased tissue angiogenesis may be one of the important causes of chronic dysfunction of stage 3 pressure injury.

Anti-arrhythmic effects of taurine-magnesium coordination compound on torsades de pointes / 中国应用生理学杂志

OBJECTIVES@#To investigate the effect of taurine magnesium coordination compound (TMCC) on torsades de pointes (TdP) in isolated guinea pig hearts.@*METHODS@#Healthy male guinea pigs weighting 250~300 g were randomly divided into 4 groups:①TdP model group (=7):Isolated hearts were perfused by normal K-H solution 20 minutes, then perfused by slowly activated delayed rectifier potassium current(IKs) blocker 10mol/L Chromanol 293B under hypokalemic solution(1.8 mmol/L) to establish TdP model;②~④ TdP model + TMCC group (=6):Isolated hearts were perfused by normal K-H solution for 20 minutes, then perfused by IKs blocker 10mol/L Chromanol 293B under hypokalemic solution(1.8 mmol/L) for 60 minutes, at the same time TMCC which concentration was 1, 2, 4 mmol/L was administered respectively by Langendorff retrograde aortic perfusion method. Cardiac surface electrocardiogram of guinea pigs was collected and recorded by Biopac electrophysiological recorder. Incidence of TdP, transmural dispersion of repolarization (TDR), instability of QT interval were acquired from Lead Ⅱ electrocardiograph (ECG) wave forms to describe the effect of TMCC on TdP model. Datas were acquired at the time of 20 min and pre-TdP, in case there was no TdP observed, a value of 60 min was entered for calculation purpose.@*RESULTS@#Incidence of TdP in TdP model group was 6/7. TdP incidence could be decreased significantly by 1, 2, 4 mmol/L TMCC, and was 5/6, 1/6, 0/6 respectively. Compared with the pre-drug, Chromanol 293B under hypokalemic solution in TdP model group increased TDR(corrected) evidently(0.05). Compared with the TdP model group, 2, 4 mmol/L TMCC could evidently decrease the instability of QT interval induced by Chromanol 293B under hypokalemic solution(<0.05). During the establishment of TdP model, P waves in more than one cardiac cycle continuously were disappeared in ECG. However, P wave could always be seen independent in ECG acquired from TdP model + TMCC group.@*CONCLUSIONS@#TMCC can play the role against TdP through decreasing TDR and instability of QT interval, and inhibiting early after depolarization(EAD).

Investigations on effect of taurine-magnesium coordination compound against SQT2 in isolated hearts of guinea pig / 中国药理学通报

Aim To investigate the effect of taurine-magnesium coordination compound (TMCC) on elec-trocardiogram of isolated guinea pig hearts, hoping to describe a primary research on its characteristic of anti-short QT syndrome. Methods The isolated guinea pig heart was retrograde perfused using Langendorff tech-nique. In order to determine the effects of TMCC on QT interval, transmural dispersion of repolarization, effective refractory period, instability of RR interval and instability of QT interval in the presence of potassi-um channel opener pinacidil, the electrocardiogram of isolated guinea pig hearts was recorded using Biopac physiological recorder. Results The shortened QT in-terval and the effective refractory period induced by pinacidil could be prolonged by TMCC; the increased transmural dispersion of repolarization induced by pinacidil could be decreased by TMCC; the increased instability of RR and QT interval induced by pinacidil could be decreased by TMCC. Conclusion TMCC has the effects of anti-SQT2 by prolonging the QT inter-val and the effective refractory period, reducing the transmural dispersion of repolarization and instability.

Effect of mallotoxin against LQT2 induced by E-4031 in isolated guinea pig hearts and cardiomyocytes / 中国药理学通报

Aim To investigate the effect of mallotoxin (MTX) on LQT2 induced by E-4031 in isolated guinea pig hearts and ventricular myocytes.Methods The isolated guinea pig heart underwent retrograde perfusion using Langendorff technique.In order to determine the effects of different concentrations of MTX on QT/QTc interval,transmural dispersion of repolarization (TDR) and index of cardiac electrophysiological balance (iCEB) in the absence and presence of hERG channel blocker E-4031,the electrocardiogram of isolated guinea pig hearts was recorded using Biopac physiological record.Single ventricular myocytes were isolated from guinea pig heart by enzymatic dissociation.Effects of MTX on action potential duration (APD) in the absence and presence of E-4031 were recorded by current clamp mode using whole patch clamp technique.Results MTX shortened the QT interval,reduced TDR,and decreased iCEB in isolated guinea pig heart.MTX could reverse the prolongation of QT interval and the increased TDR induced by E4031.MTX shortened the action potential duration and decreased APDgo,APD60 and APD30 in isolated guinea pig ventricular myocytes.MTX could reverse the prolongation of action potential repolarization duration induced by E-4031.Conclusion MTX shortens QT interval,decreases TDR,reduces iCEB,as well as shortens APD,thus reversing LQT2 induced by E4031.

Pharmaceutical inactivation of Erk1/2 does not affect function of FGF21 to regulate glucose and lipid metabolic hemostasis / 中国病理生理杂志

AIM: To investigate whether inactivation of extracellular signal-regulated kinase 1/2 ( Erk1/2 ) will affect the function of fibroblast growth factor 21 (FGF21) to regulate glucose and lipid metabolism .METHODS:Male db/db mice (8 weeks old) were treated with U0126 (an inhibitor of Erk1/2 kinase) for 1 week, and then treated with re-combinant human FGF21 protein and adenovirus-mediated FGF21 (Ad-FGF21).The profile changes of blood glucose and blood lipid were evaluated at 120 min or 4 weeks after FGF21 administration.Meanwhile, the molecular mechanism was ex-plored by in vitro study.RESULTS: Treatment of db/db mice with recombinant human FGF21 protein significantly re-duced blood glucose and triglyceride levels at 120 min after FGF21 administration , but these changes were comparable in U0126-treated mice .Furthermore , abnormal glucose and triglyceride levels , and glucose and insulin tolerance were strong-ly improved in db/db mice as accompanied with decreasing body fat content after 4 weeks of ad-FGF21 administration .In-terestingly, treatment with or without U0126 did not influence these effects of FGF21.Mechanically, treatment with Ad-FGF21 significantly upregulated the protein levels of p-Erk1/2 and peroxisome proliferator-activated receptor γ( PPARγ) as well as the expression of adiponectin at mRNA and protein levels in adipose tissues .However , treatment with or without U0126 did not change the profiles .On the other hand , in vitro experiments also indicated that treatment of adipocytes with recombinant human FGF 21 protein significantly activated Erk 1/2 phosphorylation , and upregulated the expression levels of PPARγand adiponectin (P<0.05).However, pre-administration of U0126 did not affect the profiles.CONCLUSION:Pharmaceutical inactivation of Erk 1/2 by U0216 does not affect the biological function of FGF 21 to regulate blood glucose balance and improve abnormal blood lipids in vivo.

The role of cell apoptosis mediated by endoplasmic reticulum stress (ERS) of deep tissue injury of pressure ulcer of rats / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To observe the the expression of endoplasmic reticulum stress (ERS) related factors in deep tissue injury (DTI) at pressure ulcer rat and to investigate the ERS mechanism of DTI in muscle tissue and protective effect of 4-phenylbutyric acid (4-PBA) in local tissue.</p><p><b>METHODS</b>Fifty male SD rats were randomly devided into control group, model group, experimental group NS group and PBA group, the experimental groups were divided into 4 d, 7 d, 14 d and 21 d group according to the observation time (n = 5). Rats in the PBA group were administrated with gastric perfusion of 4-PBA after the modeling; the NS group was given normal saline of the same quantity. Using HE staining to observe morphologic character. The expression of glucose regulated protein 78 (GRP78), CHOP, Caspase 12 were detected by immunohistochernical staining. Cell apoptosis was detected by TUNEL assay.</p><p><b>RESULTS</b>HE staining results showed that each group demonstrated compression injury compared with control group: cellular swelling, ompaction of nuclear, and apoptosis in muscle tissue. The new muscle fiber in 4-PBA group fused faster than those in NS group. The number of TUNEL positive cells peaked at 4 day after compression, then got decreased on day 7 in muscle tissue, apoptosis positive cells were diminished after 4-PBA treatment. The immunohistochemical staining results showed that the expression of protein GRP78, CHOP, Caspase 12 peakd 4 d after modeling and decreased gradually. The GRP78, CHOP, Caspase 12 protein expression were significantly higher than those of PBA group at all time points (P < 0.05).</p><p><b>CONCLUSION</b>Cell apoptosis induced by endoplasmic reticulum stress took part in deep tissue injury resulting of pressure ulcer, which mechanism might be related to reducing apoptosis mediated by CHOP, Caspase 12.</p>

Effects of endoplasmic reticulum stress related proteins and their mediated apoptosis in the formation of deep tissue injury of pressure ulcer in rats / 中华烧伤杂志

<p><b>OBJECTIVE</b>To explore the effects of endoplasmic reticulum stress (ERS) related proteins and their mediated apoptosis in the formation of deep tissue injury of pressure ulcer in rats.</p><p><b>METHODS</b>Forty male Sprague-Dawley rats were divided into normal control group and groups A, B, C, D according to the random number table, with 8 rats in each group. Rats in group A were loaded with 22.47 kPa pressure with a special pressure apparatus for 2.0 h in the region over gracilis, and then unloaded for 0.5 h. Rats in group B were treated with the same manoeuvre as that in group A for 3 times in one day. Rats in groups C and D were treated with the same manoeuvre as that in group B for 2 and 3 days. Rats in normal control group were free from pressure loading. Rats in groups A, B, C, and D were sacrificed after pressure loading, and then the central part of pressure loaded muscular tissues were harvested for observation of histomorphological change with HE staining; apoptotic nucleoli per millimeter pressure loaded muscular tissue were counted with Hoechst 33258 staining; the levels of binding protein (BIP), protein disulfide isomerase (PDI), C/EBP homologous protein (CHOP), and caspase-12 were assessed with Western blotting (denoted as gray level ratio of target protein to GAPDH). The same parts of gracilis of rats in normal control group were harvested for determination of all the indexes as above. Data were processed with one-way analysis of variance, LSD-t test was applied for paired comparison.</p><p><b>RESULTS</b>(1) Histomorphological observation. Some pathological changes, including inflammatory cell infiltration, myofibers lysis, and vacuolar degeneration, etc. were observed in pressure loaded muscular tissue of rats in groups A, B, C, and D, but not in the same parts of gracilis muscle of rats in normal control group. Compared with those in normal control group [(2.7 ± 1.4) per millimeter muscular tissue], the number of apoptotic nuclei was significantly increased in pressure loaded muscular tissue of rats in groups A, B, C, and D [(14.5 ± 4.4), (11.0 ± 2.9) , (13.8 ± 5.1), (21.3 ± 6.0) per millimeter pressure loaded muscular tissue, with t values from 4.223 to 6.000, P values all below 0.01). (2) Western blotting. The protein expressions of BIP and PDI in rats of normal control group and groups A, B, C, D were respectively 0.64 ± 0.12, 1.20 ± 0.34, 1.59 ± 0.24, 1.17 ± 0.28, 1.44 ± 0.33; 0.48 ± 0.15, 0.61 ± 0.19, 1.23 ± 0.38, 0.37 ± 0.19, 0.29 ± 0.15, and they showed significant statistical difference (with F values respectively 5.32, 7.95, P < 0.05 or P < 0.01). The protein expressions of CHOP and caspase-12 in rats of normal control group and groups A, B, C, D were respectively 0.58 ± 0.18, 1.48 ± 0.27, 1.03 ± 0.21, 0.95 ± 0.30, 1.69 ± 0.34; 0.55 ± 0.12, 1.08 ± 0.31, 0.69 ± 0.24, 1.79 ± 0.20, 2.06 ± 0.47, with significant statistical difference (with F values respectively 8.17, 15.48, P values all below 0.01).</p><p><b>CONCLUSIONS</b>ERS related proteins and their apoptotic pathway may play an important role in the formation of deep tissue injury of pressure ulcer in rats.</p>

Expressions of tumor necrosis factor-alpha and NF-kappa B in skeletal muscles and its effect on apoptosis in deep tissue injury of rats / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To evaluate the changes of tumor necrosis factor-alpha (TNF-alpha) and nuclear factor-kappaB (NF-kappaB) expression in muscle of pressure ulcer rats and explore the relationship with apoptosis.</p><p><b>METHODS</b>Fifty-four male SD rats were randomly divided into nine groups (n = 6), the experiment groups were pressed 9 circles (3 circles/day, 3 days), then observed on the 1st, 3rd, hematoxylin and eosin staining under the microscope; the expression of TNF-alpha was detected by Western blot; the expressions of NF-kappaB and caspase-3 were determined by immunohistochemistry, and evaluated the relationship of TNF-alpha with NF-kappaB and caspase-3; the number of apoptotic cells in compressed muscle tissue was detected by Hoechst 33258 staining under the fluorescence microscope.</p><p><b>RESULTS</b>Compared with the control group, histology examination showed that the tissue structure in experiment groups was in disorder, inter-space was wider, cell edema and the number of inflammatory cells were increased, the tissue was arranged in order and inflammatory cell recruitment was gradually attenuated. The expressions of TNF-alpha, NF-kappaB and caspase-3 were higher in the experiment groups than those in the control group (P < 0.05), reached their peak on the first day, gradually decreased on the 3nd day, but still had a significantly higher level than that in the control group (P < 0.01) on the 7th day; The number of apoptotic cells of experiment groups had a downward trend after the first rise under the fluorescence microscope; the expressions of TNF-alpha and NF-kappaB caspase-3 were found to have positive correlationship (P < 0.05), the expressions of NF-kappaB and caspase-3 were found to have positive correlationship (P < 0.01).</p><p><b>CONCLUSION</b>Apoptosis is closely correlated with inflammation in deep tissue injury of pressure ulcer, NF-kappaB plays a role not only in the formation of inflammation, but also triggering apoptosis, which may induce the pathological change and clinical progress of pressure ulcer.</p>

Expressions of vascular endothelial growth factor and basic fibroblast growth factor in the late stage of pressure ulcer / 中华烧伤杂志

<p><b>OBJECTIVE</b>To study the distribution and expressions of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) in the III-IV stage of pressure ulcer wound, and to explore their correlation with ulceration.</p><p><b>METHODS</b>Forty-one patients hospitalized in the two Affiliated Hospital of Wenzhou Medical College from June 2010 to March 2012 were recruited, including twenty-one patients with 23 pressure ulcer of stage III-IV, 14 acute injury patients, and 6 donors of normal skin. Samples harvested from the 41 patients through surgery were divided into four groups, including pressure ulcer centre group (n = 23), pressure ulcer margin group (n = 23), acute wound group (n = 14), and normal skin group (n = 6). The histological changes in wounds were observed after HE staining. The distribution of collagen fiber in wound was observed with Masson staining. Expressions of VEGF and bFGF in wounds were detected with immunohistochemical staining. Data were processed with independent samples t test and paired samples t test.</p><p><b>RESULTS</b>(1) In the two pressure ulcer groups, large number of inflammatory cells were found in aggregation; the expression of collagen fiber was decreased or disappeared; the positive expressions of VEGF and bFGF were mainly located in fibroblasts and endothelial cells. The expression levels of VEGF and bFGF were respectively 100 ± 39, 132 ± 46 in pressure ulcer centre group, and 228 ± 48, 299 ± 80 in pressure ulcer margin group. The differences between the two pressure ulcer groups were statistically significant (with t values respectively 13.497 and 13.020, P values below 0.01). (2) In acute wound group, a large number of fibroblasts but a small amount of collagen fibers were observed; the positive expressions of VEGF and bFGF were mainly located in fibroblasts, with respective expression levels of 292 ± 59 and 443 ± 194, which were significantly higher than those of the two pressure ulcer groups (with t values from 2.370 to 11.570, P < 0.05 or P < 0.01). (3) In normal skin group, structure of tissue was appropriate, and abundant collagen fibers were observed; the expression levels of VEGF and bFGF were respectively 45 ± 18 and 54 ± 22, which were significantly lower than those of the other three groups (with t values from 3.983 to 14.087, P values all below 0.01).</p><p><b>CONCLUSIONS</b>In contrast with those of the acute wounds, the expression levels of VEGF and bFGF are significantly decreased in the pressure ulcer wound at stage III-IV. It may be closely correlated with the decrease or cessation of the synthesis of collagen fiber.</p>