Under hypoxia condition, microRNA （miRNA） can interact with transcription factors for regulating the cell metabolism, angiogenesis, erythropoiesis, cellular proliferation, differentiation and apoptosis. The biological processes above may play an important role in mechanical asphyxia death. This article reviews the regulating function of miRNA under hypoxia condition and the influence of hypoxia to biosynthesis of miRNA, which may provide some new ideas to the research of miRNA on determining the cause of mechanical asphyxia death in the field of forensic medicine.
Accidents ; Airway Obstruction/physiopathology* ; Apoptosis ; Asphyxia/pathology* ; Cause of Death ; Death ; Forensic Medicine ; Humans ; Hypoxia/physiopathology* ; MicroRNAs/metabolism* ; Oxygen

OBJECTIVETo study the effect of leptin on the expression of calcium-activated neutral protease 1 (calpain-1) and B cell lymphoma-2 (Bcl-2) and apoptosis in the myocardial tissue of neonatal rats after asphyxia.

METHODSA total of 48 neonatal rats were randomly and equally divided into normal control group, asphyxia group, leptin treatment groups, and calpain-1 inhibitor (CAI-1) group. The neonatal rat model of asphyxia under normal atmospheric condition was established in all groups except the control group. For the leptin treatment groups, rats received 20, 80, and 160 μg/kg leptin by intraperitoneal injection immediately after model establishment, respectively. For the CAI-1 group, rats received 10 mg/kg CAI-1 by intraperitoneal injection immediately after model establishment. For all the groups, the myocardial tissue was collected at 2 hours after model establishment. Immunohistochemistry was used to measure the expression of calpain-1 and Bcl-2. The TUNEL method was used to evaluate apoptosis of myocardial cells.

RESULTSThe expression of calpain-1 and Bcl-2 and apoptosis index (AI) were significantly higher in the asphyxia group than in the normal control group (P˂0.05). The leptin treatment groups and the CAI-1 group had significantly lower expression of calpain-1, significantly lower AI, and significantly higher expression of Bcl-2 than the asphyxia group (P˂0.05). The CAI-1 group had the largest changes in all the indices compared with the asphyxia group. However, there were no significant differences in all indices between the 160 μg/kg leptin treatment group and the CAI-1 group. After asphyxia, the expression of calpain-1 was positively correlated with AI, while the expression of Bcl-2 was negatively correlated with AI and the expression of calpain-1 (P˂0.05).

CONCLUSIONSLeptin reduces apoptosis of myocardial cells in asphyxiated neonatal rats by the inhibition of calpain-1 activation and upregulation of Bcl-2 expression.

Animals ; Animals, Newborn ; Apoptosis ; drug effects ; Asphyxia Neonatorum ; metabolism ; pathology ; Calpain ; analysis ; antagonists & inhibitors ; Leptin ; pharmacology ; Myocardium ; metabolism ; pathology ; Proto-Oncogene Proteins c-bcl-2 ; analysis ; Rats ; Rats, Sprague-Dawley

BACKGROUNDMorbidity and mortality after resuscitation largely depend on the recovery of brain function. Ventricular fibrillation cardiac arrest (VFCA) and asphyxial cardiac arrest (ACA) are the two most prevalent causes of sudden cardiac death. Up to now, most studies have focused on VFCA. However, results from the two models have been largely variable. So, it is necessary to characterize the features of postresuscitation cerebral metabolism of both models.

METHODSForty-four Wuzhishan miniature inbred pigs were randomly divided into three groups: 18 for VFCA group, ACA group, respectively, and other 8 for sham-operated group (SHAM). VFCA was induced by programmed electric stimulation, and ACA was induced by endotracheal tube clamping. After 8 min without treatment, standard cardiopulmonary resuscitation (CPR) was initiated. Following neurological deficit scores (NDS) were evaluated at 24 h after achievement of spontaneous circulation, cerebral metabolism showed as the maximum standardized uptake value (SUVmax) was measured by 18 F-fluorodeoxyglucose positron emission tomography/computed tomography. Levels of serum markers of brain injury, neuron specific enolase (NSE), and S100β were quantified with an enzyme-linked immunosorbent assay.

RESULTSCompared with VFCA group, fewer ACA animals achieved restoration of spontaneous circulation (61.1% vs. 94.4%, P < 0.01) and survived 24-h after resuscitation (38.9% vs. 77.8%, P < 0.01) with worse neurological outcome (NDS: 244.3 ± 15.3 vs. 168.8 ± 9.71, P < 0.01). The CPR duration of ACA group was longer than that of VFCA group (8.1 ± 1.2 min vs. 4.5 ± 1.1 min, P < 0.01). Cerebral energy metabolism showed as SUVmax in ACA was lower than in VFCA (P < 0.05 or P < 0.01). Higher serum biomarkers of brain damage (NSE, S100β) were found in ACA than VFCA after resuscitation (P < 0.01).

CONCLUSIONSCompared with VFCA, ACA causes more severe cerebral metabolism injuries with less successful resuscitation and worse neurological outcome.

Animals ; Asphyxia ; complications ; physiopathology ; Brain ; metabolism ; Cardiopulmonary Resuscitation ; Heart Arrest ; metabolism ; pathology ; therapy ; Positron-Emission Tomography ; Swine ; Ventricular Fibrillation ; metabolism ; pathology ; therapy

OBJECTIVETo study the application of positron emission tomography (PET) in detection of myocardial metabolism in pig ventricular fibrillation and asphyxiation cardiac arrest models after resuscitation.

METHODSThirty-two healthy miniature pigs were randomized into a ventricular fibrillation cardiac arrest (VFCA) group (n=16) and an asphyxiation cardiac arrest (ACA) group (n=16). Cardiac arrest (CA) was induced by programmed electric stimulation or endotracheal tube clamping followed by cardiopulmonary resuscitation (CPR) and defibrillation. At four hours and 24 h after spontaneous circulation was achieved, myocardial metabolism was assessed by PET. 18F-FDG myocardial uptake in PET was analyzed and the maximum standardized uptake value (SUVmax) was measured.

RESULTSSpontaneous circulation was 100% and 62.5% in VFCA group and ACA group, respectively. PET demonstrated that the myocardial metabolism injuries was more severe and widespread after ACA than after VFCA. The SUVmax was higher in VFCA group than in ACA group (P<0.01). In VFCA group, SUVmax at 24 h after spontaneous circulation increased to the level of baseline.

CONCLUSIONACA causes more severe cardiac metabolism injuries than VFCA. Myocardial dysfunction is associated with less successful resuscitation. Myocardial stunning does occur with VFCA but not with ACA.

Animals ; Asphyxia ; physiopathology ; Cardiopulmonary Resuscitation ; Gene Expression Regulation ; Heart Arrest ; etiology ; metabolism ; therapy ; Myocardium ; metabolism ; Positron-Emission Tomography ; methods ; Random Allocation ; Swine ; Ventricular Fibrillation ; metabolism

In practice of forensic medicine, potential disease can be associated with fatal asphyxia in restraint position. Research has demonstrated that nitric oxide (NO) and nitric oxide synthase (NOS) are plentifully distributed in skeletal muscle, contributing to the regulation of contractile and relaxation. In the current study, respiratory functions, indices of diaphragmatic biomechanical functions ex vivo, as well as NO levels in serum, the expressions of diaphragmatic inducible NOS (iNOS) mRNA, and the effects of L-NNA on contractility of the diaphragm were observed in sepsis induced by cecal ligation and puncture (CLP) under the condition of restraint position. The results showed that in the CLP12-18h rats, respiratory dysfunctions; indices of diaphragmatic biomechanical functions (Pt, +dT/dt(max), -dT/dt(max), CT, Po, force over the full range of the force-frequency relationship and fatigue resistance) declined progressively; the NO level in serum, and iNOS mRNA expression in the diaphragm increased progressively; force increased significantly at all stimulation frequencies after L-NNA pre-incubation. Restraint position 1 h in CLP12 h rats resulted in severe respiratory dysfunctions after relative stable respiratory functions, almost all the indices of diaphragmatic biomechanical functions declined further, whereas little change took place in NO level in serum and diaphragmatic iNOS mRNA expression; and the effects of L-NNA were lack of statistical significance compared with those of CLP12 h, but differed from CLP18 h group. These results suggest that restraint position and sepsis act together in a synergistic manner to aggravate the great reduction of diaphragmatic contractility via, at least in part, the negative modulation of NO, which may contribute to the pathogenesis of positional asphyxia.
Animals ; Asphyxia ; Diaphragm/physiology* ; Muscle Contraction ; Muscle, Skeletal ; Nitric Oxide/metabolism* ; Nitric Oxide Synthase ; Nitric Oxide Synthase Type II ; Rats ; Respiration Disorders ; Restraint, Physical ; Sepsis

OBJECTIVE: To observe the postmortem degradation process in rat myocardium and skeletal muscle using Fourier transform infrared (FTIR) spectroscopy and to provide a new method for estimating postmortem interval (PMI). METHODS: Left ventricle and skeletal muscles of rats dying of mechanical asphyxiated were sampled at different PMIs. The changes of different chemical functional group in the myocardium and skeletal muscle samples were measured by FTIR spectroscopy. The different absorbance (A) ratios of peaks were calculated and the curve estimation analysis between absorbance ratios (x) and PMI (y) were performed to establish six mathematical models. RESULTS: FTIR spectral absorption peak of rat myocardium and skeletal muscle showed three changes: increase, decrease and stable. The cubic model function showed the strongest correlation coefficient. The A1080/A1396 ratio of skeletal muscle showed the strongest correlation coefficient (r = 0.832) with more accurate determination of PMI. CONCLUSION FYIR spectroscopy can be potentially used as an effective method for estimating PMI in forensic practice using myocardium and skeletal muscle.
Animals ; Asphyxia/metabolism* ; Forensic Pathology/methods* ; Male ; Muscle, Skeletal/metabolism* ; Myocardium/metabolism* ; Postmortem Changes ; Rats ; Rats, Sprague-Dawley ; Spectroscopy, Fourier Transform Infrared ; Time Factors

OBJECTIVE: Fourier transform infrared (FTIR) spectroscopy was applied to observe the postmortem degradation process in mechanical asphyxiated rat's liver and spleen for providing a new method of estimating PMI. METHODS: Rats were sacrificed by mechanical asphyxia and cadavers were kept at (20 +/- 2) degrees C in a control chamber. The liver and spleen were sub-sampled from the same rat at intervals of 0-15 days postmortem and the data were measured by FTIR spectrometer. The different absorbance (A) ratios of peaks were calculated and the curve estimation analysis between absorbance ratios (x) and PMI (y) were performed to establish mathematical models by the statistical software. RESULTS: The band absorbance ratios showed increase, decrease and stable with PMI. The cubic model functions showed the strongest correlation coefficient. Compared with the spleen, the liver showed a higher correlation coefficient. The A1541/A1396 of liver showed the highest correlation coefficient (r=0.966). After 6-7 days postmortem, band absorbance ratios showed a steady period. CONCLUSION FTIR spectroscopy can be a new and efficient method to estimate PMI within 7 days.
Animals ; Asphyxia/metabolism* ; Autopsy ; Cadaver ; Forensic Pathology/methods* ; Liver/pathology* ; Models, Theoretical ; Postmortem Changes ; Rats ; Rats, Sprague-Dawley ; Regression Analysis ; Spectroscopy, Fourier Transform Infrared ; Spleen/pathology* ; Time Factors

OBJECTIVETo investigate, from cytoprotein and molecular levels, the action mechanism of astragalus injection (ASI) on the signal conduction of human renal tubular cells (HK-2) injury induced by neonatal postasphyxial-serum (NPS), whether it is through activating the nuclear factor kappaB (NF-kappaB) signaling pathway.

METHODSTaking HK-2 as the target cell and the 20% NPS as the attacking factor, the experiment was conducted by dividing the target cells into two groups before attacking, the blank control group and the ASI pretreated group. The nuclear translocation of NF-kappaB was detected by confocal microscopy with indirect immunofluorescence stain, and the amount of NF-kappaB inhibitor subunit (I-kappaBalpha) was detected by Western blot before attacking. The detections were repeated at various time points in the experiment, i.e., 15 min, 1 h and 2 h after attacking, respectively.

RESULTSBefore attacking, the nuclear translocation of NF-kappaB and the amount of I-kappaBalpha were not different in the two groups. But the former increased and the latter decreased significantly in the ASI group at all the time points after attacking with the topmost changes presented at 1 h after attacking, and significantly different to those in the control group at corresponding time

CONCLUSIONASI pretreatment could inhibit the activation of NF-kappaB induced by postasphyxial-serum.

Apoptosis ; Asphyxia Neonatorum ; blood ; Astragalus Plant ; Cell Line ; Humans ; I-kappa B Proteins ; metabolism ; Infant, Newborn ; Kidney Tubules ; cytology ; metabolism ; NF-KappaB Inhibitor alpha ; Signal Transduction

OBJECTIVETo investigate the expression of serine protease Omi/HtrA2 in kidneys of postasphyxial neonatal rats, and to study the effects of Ucf-101 on apoptosis and the expression of Omi/HtrA2 in these rats.

METHODSSeventy-two neonatal Wistar rats of 7-10 days old were randomly divided into 3 groups: control, postasphyxial model, Ucf-101-treated postasphyxialThe postasphyxial model was established by normobaric asphyxiaExpression of Omi/HtrA2 was determined with streptavidin-peroxidase immunohistochemistry 2, 24 and 48 hrs after asphyxia. Terminal deoxynuleotidyl-mediated nick end labeling (TUNEL) was used to ascertain the apoptosis of renal cells.

RESULTSCompared with the control group, OmiHtrA2 expression in renal cells began to increase 2 hrs after asphyxia and peaked at 24 hrs. The expression of Omi/HtrA2 in the Ucf-101-treated postasphyxial group was significantly lower than that in the postasphyxial model group (P<0.01). TUNEL-positive cells began to increase 2 hrs after asphyxia and peaked at 24 hrs in the postasphyxial model group when compared with the control group. The number of TUNEL-positive cells in the Ucf-101-treated postasphyxial group was significantly lower than that in the postasphyxial model group at all time points (P<0.01).

CONCLUSIONSThe expression of Omi/HtrA2 in kidneys is increased in postasphyxial neonatal rats. The increased Omi/HtrA2 expression may play an important role in the development of postasphyxial renal injury. Treatment with Ucf-101 can reduce the expression of Omi/HtrA2 in kidneys of postasphyxial neonatal rats and thus reduce renal tububar epithelial cell apoptosis.

Animals ; Animals, Newborn ; Apoptosis ; drug effects ; Asphyxia Neonatorum ; drug therapy ; metabolism ; pathology ; Female ; High-Temperature Requirement A Serine Peptidase 2 ; Humans ; Immunohistochemistry ; In Situ Nick-End Labeling ; Infant, Newborn ; Kidney ; chemistry ; Male ; Mitochondrial Proteins ; analysis ; antagonists & inhibitors ; Pyrimidinones ; pharmacology ; therapeutic use ; Rats ; Rats, Wistar ; Serine Endopeptidases ; analysis ; Thiones ; pharmacology ; therapeutic use

Pericardial fluid is a kind of serous fluid in pericardial cavity. Because blood undergoes postmortem changes such as autolysis and putrefaction, vitreous humor is limited,cerebrospinal fluid is easily mixed with blood, pericardial fluid, on the other hand, exists in a closed cavity and can be hardly contaminated by postmortem changes, and also is easily obtained. Pericardial fluid not only plays an important role in clinic practice, but also is widely applicable in forensic practice. This paper briefly presented the properties of pericardial fluid and its clinical significance. It reviewed biochemical changes in decedents died of heart diseases, drowning and asphyxia, and explored the significance in medico-legal investigation. Moreover, application of pericardial fluid in forensic serology, forensic toxicological analysis and other fields were also discussed. Pericardial fluid analysis may provide important information for determination of the cause of death with further investigation concerning forensic applicability of pericardial fluid.
Asphyxia/pathology* ; Atrial Natriuretic Factor/metabolism* ; Biomarkers/metabolism* ; Calcium/metabolism* ; Drowning/pathology* ; Forensic Pathology ; Heart Diseases/pathology* ; Humans ; L-Lactate Dehydrogenase/metabolism* ; Magnesium/metabolism* ; Myocardium/metabolism* ; Natriuretic Peptide, Brain/metabolism* ; Pericardium/metabolism* ; Postmortem Changes ; Troponin I/metabolism*