[The influence of JNK inhibitor on hemodynamics after ischemia/reperfusion injury to the heart in rats].

OBJECTIVE: To investigate the effect and mechanism of JNK mitogen-activated protein kinases (JNK MAPKs) inhibitor SP 600125 on hemodynamics after ischemia/reperfusion (I/R) injury to heart in anesthetized rats. METHODS: Thirty-six healthy adult Sprague-Dawley (SD) rats were randomly divided into six groups (each n=6): sham operation (SO) group, I/R group, three JNK inhibitor groups (model groups) and ligustrazine hydrochloride (LH) group. In the SO group, a silk suture was passed underneath a main branch of the left coronary artery without tying. In the rest groups, the left coronary artery was occluded lasting for 30 minutes followed by reperfusion for 180 minutes. In the model groups, SP 600125 was intravenously administered 5 minutes before the end of the ischemia period, and continued during reperfusion period with a total dose of 4.7, 14.4 and 47.9 mg/kg respectively. Control animals received normal saline or LH 30 mg/kg in the same manner. The changes in hemodynamics, including heart rate (HR), mean blood pressure (MBP), maximal change rate of intraventricular pressure rise/down (+/-dp/dt max),left ventricular systolic pressure (LVSP), LVDP' [LVDP'=LVSP-left ventricular diastolic pressure (LVDP)], left ventricular end-diastolic pressure (LVEDP), were determined during I/R. RESULTS: There was no statistical difference in hemodynamics among the groups before occluding. The values of HR, MAP, +/-dp/dt max, LVSP, LVDP' in I/R group were significantly lower than those in SO group, and LVEDP was significantly higher. Compared with I/R group, +/-dp/dt max, LVSP, LVDP' in model groups and LH group were significantly higher (P<0.05 or P<0.01). There was no significant change in HR, MBP and LVEDP after the administration of JNK inhibitor or LH. CONCLUSION: Both JNK inhibitor and LH ameliorate cardiac systolic and diastolic dysfunction induced by I/R, without influence on MBP and HR in anesthetized rats.

[Advance in the research of platelet-rich plasma in burn treatment].

Platelet-rich plasma (PRP) is the plasma derived from the repeatedly centrifuged whole blood, and it contains high concentration of platelets. The growth factors and concentrated platelets in PRP play important roles in proliferation, division, and differentiation of cells, and wound repair. In the past, PRP was used in the treatment of bone fracture, bone defect, soft tissue injury, and refractory wound. In recent years, it had been used in burn treatment, but it provoked some disputes. This article reviews the advance in the research of PRP in burn treatment and discusses the problems in its clinical application.

[Improving myocardial mechanics parameters of severe burn rabbits with oral fluid resuscitation].

OBJECTIVE: To investigate the protective effect of oral fluid resuscitation on cardiac function in severe burn rabbits. METHODS: One hundred and fifty rabbits were randomly divided into normal control group (NC group, n = 6, without treatment), burn group (B group, n = 42, without fluid therapy), immediate oral fluid resuscitation group (C group, n = 42), delayed oral fluid resuscitation group (D group, n = 30) and delayed and rapid oral fluid resuscitation group (E group, n = 30). The rabbits in B, C, D, E groups were subjected to 40% TBSA full-thickness burn, then were treated with fluid therapy immediately after burn (C group), at 6 hour after burn (D, E groups). The myocardial mechanics parameters including mean arterial pressure (MAP), left ventricular systolic pressure (LVSP), left ventricular end diastolic pressure (LVEDP), LV +/- dp/dt max were observed at 2, 6, 8, 12, 24, 36 and 48 post burn hour (PBH). Urine output was also examined. RESULTS: The level of LVSP, LV +/- dp/dt max in B roup were significantly lower than those in NC group. The level of LVSP, LV +/- dp/dt max in the C and E group were singnificantly increased during 24 hour after burn. The level of LV + dp/dt max and LV-dp/dt max in C group peaked at 8 PBH (892 +/- 116 kPa/s) and at 6PBH (724 +/- 149 kPa/s) respectively. The levels of LV +/- dp/dt max, LVSP in D group at each time point were similar to B group (P > 0.05). Both the levels of LV +/- dp/dt max in E group peaked at 8 PBH. The level of LVEDP was no obvious difference between B and other groups at each time point (P > 0.05). The changes of MAP and urine output on 24 PBH in each group were similar to above indices. CONCLUSION: Effective oral fluid therapy in severe burn rabbits during 24 hours after burn can ameliorate myocardial mechanics parameters. The amount of fluid resuscitation can be estimated according to relevant formula for delayed fluid resuscitation in burn rabbits.

[The protective effect of high density lipoprotein on the lung function of rats with severe burns].

OBJECTIVE: To explore the protective effect of high density lipoprotein on the lung function of rats with severe burns. METHODS: One hundred and thirty-five Wistar rats were employed in the study and were randomly divided into control (n = 15, without injury), burn (n = 60, with 30% TBSA full-thickness burn on the back) and experimental [(n = 60, with the injection of HDL (80 mg/kg) via the caudal vein immediately after burns)] groups. The rats in the latter two groups were resuscitated with intraperitoneal isotonic saline (50 ml/kg) 30 minutes after burns. The serum content of ICAM-1 and TNF-alpha as well as the blood content of PCO2 and PO2 of the rats in burn and experimental groups were determined at 12, 24, 48 and 72 post-burn hours (PBH) and in control group. The pathological changes in the lung tissue of the rats in all groups were observed under light microscope and electronic microscope at 48 PBH. RESULTS: PCO2 and the contents of ICAM-1 and TNF-alpha in burn group were significantly higher, but the PO2 was lower than those in control group at each time-point (P < 0.05 or P < 0.01). There were no obvious differences in the above indices between the experimental and control groups (P > 0.05), but the ICAM-1 and TNF-alpha levels in experimental group were markedly decreased than those in burn group at each time-point (P < 0.05 or P < 0.01). The ICAM-1 and TNF-alpha contents in burn group at 48 PBH were (3.42 +/- 0.25) microg/L and (4. 04 +/- 0.28) ng/L, respectively, which were markedly higher than those in experimental group [(2.24 +/- 0.14) microg/L, (3.35 +/- 0.22) ng/L, P < 0.05 or P < 0.01]. Dilation of capillaries, congestion and inflammatory infiltration in the pulmonary capillaries, and loosening of conjunction between pulmonary capillary vascular endothelial cells and endothelial swelling were observed in burn group at 48 PBH. Compared with the burn group, the injury was markedly alleviated in the experiment group, and the pulmonary capillary endothelial cells showed tighter junction. CONCLUSION: HDL exhibits a protective effect on the lung function of rats with severe burns via reducing the expression of ICAM-1 and TNF-alpha.

[Genioplasty with morselized autologous bone graft].

OBJECTIVE: To investigate a new method of genioplasty for treatment of a prominent mandibular angle with mandibular malformation. METHODS: According to the different types of the mandible, the prominent mandibular angle was grinded with the masseter muscle kept intact. Autologous micromorselized bone of the grinded mandibular angle was collected and implanted into the chin for augmentation mentoplasty, and the chin was fixed with gypsum after operation. RESULTS: Fifteen patients receiving the surgery were followed up for 6 -12 months, and satisfactory effects were achieved in 12 patients. One patient requested modification of the shape of the chin 10 days after the operation, and another two sustained chin distortion due to external forces and underwent subsequent shape adjustment of the chin. CONCLUSION: The procedure described avoids graft rejection and causes less complications for genioplasty with easy moulding and satisfactory outcome.

[Expression of alpha-melanocyte-stimulating hormone in human split-thickness skin graft].

OBJECTIVE: To investigate the expression of alpha-melanocyte-stimulating hormone (alpha-MSH) in human split-thickness skin autograft and the role of alpha-MSH in hyperpigmented process of the grafted skin. METHODS: Immunohistochemical technique was used to detect the expression and distribution of alpha-MSH in the split-thickness grafted skin and normal skin separately. RESULTS: The expression of alpha-MSH in most of the split-thickness grafted skin was much stronger than the control skin. The positive ratio of alpha-MSH expression was 61.1% in the split-thickness grafted skin, 11.1% in the normal skin of the donor area and 16.7% in the normal skin around the recipient area. The expression of alpha-MSH in the split-thickness grafted skin was significant high, compared with the normal skins (P < 0.01). The expression of alpha-MSH in the normal skin of the donor area was no statistic remarkably differences compared to the normal skin around the recipient area. CONCLUSION: The results indicate that the expression of alpha-MSH may markedly increase in the split-thickness grafted skin and correlate with its pigmentation after the skin graft. Overexpression of alpha-MSH may play an important role in hyperpigmented process of the skin graft.