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Objective To evaluate the effect of dexmedetomidine on phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt)/glycogen synthase kinase-3 beta (GSK-3β) signaling pathway during apoptosis in cardiomyocytes of rats with severe scald.Methods Twenty-four healthy adult male SpragueDawley rats,weighing 220-280 g,were divided into 3 groups (n=8 each) using a random number table method:control group (group C),severe scald group (group S) and dexmedetomidine group (group D).Thirty percent of the total body surface area was shaved on the back and then exposed to 94 ℃ water (with 37 ℃ warm water in group C) for 12 s to establish the model of third degree scald in pentobarbital sodium-anesthetized rats.Dexmedetomidine 30 μg/kg (2 μg/ml) was intraperitoneally injected immediately after scald in group D.Rats received anti-shock treatment by intraperitoneal injection of isotonic saline according to Parkland formula,and group C received no injection.Rats were anesthetized using the method previously mentioned at 12 h after treatment,and myocardial specimens of the left ventricle were rapidly excised and stored at-80 ℃ for determination of cell apoptosis (by TUNEL) and expression of P13K,phosphorylated Akt (p-Akt) and phosphorylated GSK-3β (p-GSK-3β) (by Western blot).Apoptosis index (AI) was calculated.Results Compared with group C,AI was significantly increased,and the expression of P13K,p-Akt and p-GSK-3β was up-regulated in S and D groups (P＜0.05).Compared with group S,AI was significantly decreased,and the expression of P13K,p-Akt and p-GSK-3β was up-regulated in group D (P＜0.05).Conclusion Dexmedetomidine inhibits apoptosis in cardiomyocytes through activating PI3K/Akt/GSK-3β signaling pathway in the rats with severe scald.
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Objective To investigate the effect of dexmedetomidine on protein kinase RNA-like endoplasmic reticulum kinase (PERK) signaling pathway in cardiomyocytes of the rats with severe scald.Methods Twenty-four healthy adult male Sprague-Dawley rats,weighing 220-280 g,were randomly divided into 3 groups (n =8 each) using a random number table:control group (group C),severe scald group (group S),and scald + dexmedetomidine group (group D).Thirty percent of the total body surface area was shaved on the back and then exposed to 94 ℃ water for 12 s to establish the model of 3rd degree scald.Dexmedetomidine 30 μg/kg (2 μg/ml) was intraperitoneally injected immediately after scald in group D.Myocardial specimens were obtained at 12 h after scald for examination of the pathological changes and for determination of cell apoptosis and expression of C/EBP-homologous protein (CHOP),PERK,and phosphorylated PERK (p-PERK) by Western blot.The apoptosis index and p-PERK/PERK ratio were calculated.Results Compared with group C,the apoptosis index was significantly increased,the expression of CHOP,PERK and p-PERK was significantly up-regulated,and the p-PERK/PERK ratio was significantly increased in S and D groups (P＜0.05).Compared with group S,the apoptosis index was significantly decreased,the expression of CHOP,PERK and p-PERK was significantly down-regulated,and the p-PERK/PERK ratio was significantly decreased (P＜0.05),and the pathological changes of myocardium were significantly attenuated in group D.Conclusion The mechanism by which dexmedetomidine inhibits apoptosis in cardiomyocytes is related to inhibition of PERK signaling pathway in the rats with severe scald.
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Objective To evaluate the effect of acute hypervolemic hemodilution (AHH) on myocardial damage in severely burned rabbits.Methods Eighteen healthy adult rabbits,weighing 2.0-2.5 kg,were randomly divided into 3 groups (n =6 each) using a random number table:control group (group C),burn group (B group) and AHH group.Rabbits were subjected to 3rd degree burn covering 40％ of the total body surface area.After the model was established,6％ hydroxyethyl starch 130/0.4 was infused intravenously,and the target Hct was 25％ in AHH group.Before AHH (To) and at 2,4 and 8 h after AHH (T1-3),left ventricular systolic pressure (LVSP),left ventricular end-diastolic pressure (LVEDP),+dp/dtmax and-dp/dtmax were recorded,and blood samples from femoral veins were taken to determine the concentration of serum cardiac troponin I (cTnI) by ELISA.The rabbits were sacrificed at T3,and myocardial specimens were removed for microscopic examination of pathological changes with light microscope.Results Compared with group C,the serum cTnI concentration and LVEDP were significantly increased,LVSP and +dp/dtmaxwere decreased at T1-3 in B and AHH groups,and-dp/dtmax at T1-3 in group B and-dp/dtmax at T3 in group AHH were decreased.Compared with group B,LVSP,+dp/dtmax and-dp/dtm,x were significantly increased at T1-3,and no significant change was found in serum cTnI concentration and LVEDP in group AHH.There was no significant difference in the pathological changes between group B and group AHH.Conclusion AHH can not aggravate the early myocardial damage in severely burned rabbits.
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In this paper, we generalized the basic concept of ability health management and discussed its core connota -tion in terms of ability health measurement , ability health assessment and ability training .After defining ability health meas-urement, outlined the process of determining the measurement items and listed the main contents of measurement standardi -zation.Further, we systematically analyzed the basic components of ability health assessment , including the index system , standards, methods and process .We also discussed the function , classification and principle of ability training .Finally, we drew the conclusion that the goal of ability health management is to improve the ability health level so as to consolidate and promote the operation capability of military personnel .
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<p><b>OBJECTIVE</b>To observe the effects of preconditioning with different concentrations of sevoflurane on cariomyocyte apoptosis and myocardial inflammation in rats with sepsis and explore the possible mechanism of sevoflurane for myocardial protection.</p><p><b>METHODS</b>Forty adult male Sprague-Dawley rats were randomly divided into 4 groups (n=10), namely the control group, LPS group, low-concentration sevoflurane group and high-concentration sevoflurane group. Following sevoflurane pretreatment for 30 min and a washout period for 10 min, all the rats received intraperitoneal injection of LPS or normal saline (NS) and were sacrificed 12 h later to observe the myocardial histopathology. Apoptosis of the ardiomyocytes was detected with TUNEL assay, and enzyme-linked immunosorbent assay was used to detect serum cTnI level and myocardial TNF-α level.</p><p><b>RESULTS</b>Compared with the control group, the rats in the other 3 groups showed significantly increased serum cTnI level, myocardial TNF-α content, and apoptotic index of the cardiomyocytes (P<0.05). Compared with those in LPS group, serum cTnI level, myocardial TNF-α content, and apoptotic index of the cardiomyocytes were significantly decreased in the two sevoflurane preconditioning groups (P<0.05), and the effect was more obvious with a high dose of sevoflurane (P<0.05 CONCLUSION: Sevoflurane preconditioning can concentration-dependently reduce LPS-induced myocardial injury in rats possibly by decreasing cardiomyocyte apoptosis and alleviating myocardial inflammations.</p>
Subject(s)
Animals , Male , Rats , Apoptosis , Methyl Ethers , Pharmacology , Myocarditis , Drug Therapy , Myocardium , Pathology , Myocytes, Cardiac , Cell Biology , Rats, Sprague-Dawley , Sepsis , Troponin I , Blood , Tumor Necrosis Factor-alpha , MetabolismABSTRACT
Objective To evaluate the effect of dexmedetomidine on apoptosis in myocardial cells in rats with severe scald.Methods Eighteen healthy male Sprague-Dawley rats,weighing 220-280 g,were randomly divided into 3 groups (n =6 each) using a random number table:control group (group C),scald group (group B)and scald + dexmedetomidine 30 μg/kg group (group D).Thirty percent of the total body surface was shaved and then exposed to 94 ℃ water for 12 s.Rats were resuscitated with isotonic saline according to Parkland formula immediately after burn.Sham burn was produced in C group.In group D,the rats received inraperitoneal injection of dexmedetomidine 30 μg/kg immediately after burn,and the equal volume of normal saline was injected in group B.The left ventricle was removed at 12 h after burn to observe the pathological changes of myocardial tissues with light microscope and to detect the apoptosis in myocardial cells (TUNEL assay) and expression of glucose-regulated protein 78 (GRP78) and C/EBP-homologous protein (CHOP) (using Western blot).The apoptosis index was calculated.Results Compared with group C,the apoptosis index was significantly increased and the expression of GRP78 and CHOP was up-regulated in B and D groups (P ＜ 0.05).Compared with group B,the apoptosis index was significantly decreased and the expression of GRP78 and CHOP was down-regulated in group D (P ＜ 0.05).The pathological changes were obvious in group B and were significantly attenuated in group D.Conclusion Dexmedetomidine can protect myocardium through inhibiting endoplasmic reticulum stress-mediated apoptosis in myocardial cells in rats with severe scald.
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Objective Pulmonary dysfunction is common in the obese patients after laparoscopic surgery. To reduce or avoid this complication caused by improper combination of mechanical ventilatory parameters,we conducted the following trial of 3 factors with 3 levels of mechanical ventilation in order to explore the optimal combination with low airway pressure. Methods Patients were randomly allocated into 9 groups (k=3,n=27) according to the "30≤BMI<40" obesity index (ASAⅠ-Ⅱ). Anesthesia machine parameters were set as follows: respiratory frequency (f), tidal volume (VT), respiratory ratio (I:E) as the three factors of A, B, C, with 3 levels of f=15, 12, 9 (bpm), VT=8, 10, 12 (mL/kg), I:E=1:2.5, 1:2.0, 1:1.5. By using L9(3~4)K=3 repeat orthogonal experimental design and analysis table, the variable factors that affect the respiratory index such as the end tidal carbon dioxide pressure (P_(ET)CO_2), peak airway pressure (PIP), mean airway pressure (P_(mean)), and the end of endogenous airway pressure (PEEPi) were analyzed. Results In this study, 27 cases undergoing laparoscopic surgery under general anesthesia were allocated into 9 experimental groups. The hemodynamics of these patients was stable, SPO_2 was kept at 100 percent during the operation. The results of different combinations were described as follows: ①P_(ET)CO_2: f and VT with different level had great impact on P_(ET)CO_2 (P<0.01), I:E had no significant difference in three levels (P>0.05);② PIP: f had great effect on PIP (P<0.05);VT and I:E in three levels also had significant effect on PIP(P<0.01);③ P_(mean): all the ventilation parameters with different combination had significant effect on P_(mean)(P<0.01). Conclusions The best combination of respiratory parameters is A3B1C2, i.e., f=9 bpm, VT=8 mL/kg, and I:E=1:2.0, which indicates that neither small tidal volume and faster frequency, nor slow frequency large tidal volume is a good choice. In order to let obese patients under general anesthesia obtain the best lung protective effect by low airway pressure with good ventilation, it is worth noting that: ①I:E has a great effect on airway pressure (PIP, P_(mean)), which is important for lung protection;②I:E has the opposite effect on PIP and P_(mean).