ABSTRACT
BACKGROUND: Exposure to high sustained +Gz (head-to-foot inertial load) is known to have harmful effects on pilots' body in flight. Although clinical data have shown that liver dysfunction occurs in pilots, the precise cause has not been well defined. AIM: To investigate rat liver function changes in response to repeated +Gz exposure. METHODS: Ninety male Wistar rats were randomly divided into a blank control group (BC group, n = 30), a +6 Gz/5 min stress group (6GS group, n = 30), and a +10 Gz/5min stress group (10GS group, n = 30). The 6GS and 10GS groups were exposed to +6 Gz and +10 Gz, respectively, in an animal centrifuge. The onset rate of +Gz was 0.5 G/s. The sustained time at peak +Gz was 5 min for each exposure (for 5 exposures, and 5-min intervals between exposures for a total exposure and non-exposure time of 50 min). We assessed liver injury by measuring the portal venous flow volume, serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST), liver tissue malondialdehyde (MDA), Na+-K+-ATPase, and changes in liver histology. These parameters were recorded at 0 h, 6 h, and 24 h after repeated +Gz exposures. RESULTS: After repeated +Gz exposures in the 6GS and the 10GS groups, the velocity and flow signal in the portal vein (PV) were significantly decreased as compared to the BC group at 0 h after exposure. Meanwhile, we found that the PV diameter did not change significantly. However, rats in the 6GS group had a much higher portal venous flow volume than the 10GS group at 0 h after exposure. The 6GS group had significantly lower ALT, AST, and MDA values than the 10GS group 0 h and 6 h post exposure. The Na+-K+-ATPase activity in the 6GS group was significantly higher than that in the 10GS group 0 h and 6 h post exposure. Hepatocyte injury, determined pathologically, was significantly lower in the 6GS group than in the 10GS group. CONCLUSION: Repeated +Gz exposures transiently cause hepatocyte injury and affect liver metabolism and morphological structure.
Subject(s)
Acceleration/adverse effects , Hypergravity/adverse effects , Liver Diseases/physiopathology , Liver/injuries , Stress, Physiological , Aerospace Medicine , Animals , Blood Flow Velocity , Centrifugation/adverse effects , Disease Models, Animal , Hepatocytes/metabolism , Hepatocytes/pathology , Humans , Liver/blood supply , Liver/cytology , Liver/pathology , Liver Diseases/etiology , Liver Function Tests , Male , Pilots , Portal Vein/physiopathology , Rats , Rats, WistarABSTRACT
Gabexate mesilate (GM) is a trypsin inhibitor, and mainly used for treatment of various acute pancreatitis, including traumatic pancreatitis (TP), edematous pancreatitis, and acute necrotizing pancreatitis. However, due to the characteristics of pharmacokinetics, the clinical application of GM still needs frequently intravenous administration to keep the blood drug concentration, which is difficult to manage. Specially, when the blood supply of pancreas is directly damaged, intravenous administration is difficult to exert the optimum therapy effect. To address it, a novel thermosensitive in-situ gel of gabexate mesilate (GMTI) was developed, and the optimum formulation of GMTI containing 20.6% (w/w) P-407 and 5.79% (w/w) P188 with different concentrations of GM was used as a gelling solvent. The effective drug concentration on trypsin inhibition was examined after treatment with different concentrations of GMTI in vitro, and GM served as a positive control. The security of GMTI was evaluated by hematoxylin-eosin (HE) staining, and its curative effect on grade II pancreas injury was also evaluated by testing amylase (AMS), C-reactive protein (CRP) and trypsinogen activation peptide (TAP), and pathological analysis of the pancreas. The trypsin activity was slightly inhibited at 1.0 and 5.0 mg/mL in GM group and GMTI group, respectively (P<0.05 vs. P-407), and completely inhibited at 10.0 and 20.0 mg/mL (P<0.01 vs. P-407). After local injection of 10 mg/mL GMTI to rat leg muscular tissue, muscle fiber texture was normal, and there were no obvious red blood cells and infiltration of inflammatory cells. Furthermore, the expression of AMS, CRP and TAP was significantly increased in TP group as compared with control group (P<0.01), and significantly decreased in GM group as compared with TP group (P<0.01), and also slightly inhibited after 1.0 and 5.0 mg/mL GMTI treatment as compared with TP group (P<0.05), and significantly inhibited after 10.0 and 20.0 mg/mL GMTI treatment as compared with TP group (P<0.01). HE staining results demonstrated that pancreas cells were uniformly distributed in control group, and they were loosely arranged, partially dissolved, with deeply stained nuclei in TP group. Expectedly, after gradient GMTI treatment, pancreas cells were gradually restored to tight distribution, with slightly stained nuclei. This preliminary study indicated that GMTI could effectively inhibit pancreatic enzymes, and alleviate the severity of trauma-induced pancreatitis, and had a potential drug developing and clinic application value.
Subject(s)
Delayed-Action Preparations/pharmacology , Gabexate/pharmacology , Pancreatitis/drug therapy , Serine Proteinase Inhibitors/pharmacology , Wounds, Penetrating/drug therapy , Amylases/metabolism , Animals , C-Reactive Protein/metabolism , Delayed-Action Preparations/chemical synthesis , Delayed-Action Preparations/pharmacokinetics , Gabexate/chemistry , Gabexate/pharmacokinetics , Gels , Male , Muscle, Skeletal/drug effects , Muscle, Skeletal/enzymology , Oligopeptides/metabolism , Pancreas/drug effects , Pancreas/enzymology , Pancreas/pathology , Pancreatitis/enzymology , Pancreatitis/etiology , Pancreatitis/pathology , Poloxamer/chemistry , Rats , Rats, Sprague-Dawley , Serine Proteinase Inhibitors/chemistry , Serine Proteinase Inhibitors/pharmacokinetics , Temperature , Wounds, Penetrating/complications , Wounds, Penetrating/enzymology , Wounds, Penetrating/pathologyABSTRACT
The function of the transplanted heart will be affected by acute allograft rejection, chronic rejection, high blood pressure and so on, which may induce the reconstruction of the left ventricle and the increase of left ventricular mass (LVM), and eventually lead to left ventricular hypertrophy that will significantly affect the prognosis of heart transplantation (HT). The purpose of this study was to dynamically monitor the changes of left ventricular geometric patterns after HT using two-dimensional echocardiography and to understand the remodeling process and its possible influencing factors. The left ventricular internal diameter, interventricular septal wall thickness, posterior wall thickness at end diastole were measured and the relative wall thickness (RWT), left ventricular mass, left ventricular mass index were calculated respectively in 34 HT patients and 34 healthy volunteers by two-dimensional echocardiography. The type of left ventricular geometry was identified based on the echocardiographic determination of LVM index (LVMI) and RWT. The HT patients were divided into three groups according to the time length after surgery: A (3 months postoperatively), B (6 months postoperatively) and C (12 months postoperatively). We compared the parameters of left ventricle between HT group and normal control group, and explored the risk factors causing the increase of LVM. The results showed that 4 patients (16%) in group A had concentric remodeling. Nine patients (34.62%) in group B had reconstruction, including 5 cases of concentric remodeling, 2 cases of concentric hypertrophy and 2 cases of eccentric hypertrophy. The hypertrophy incidence rate was 15.4% in group B. 15 patients (62.5%) had reconstruction in group C, including 9 cases of concentric remodeling, 5 cases of concentric hypertrophy, and 1 case of eccentric hypertrophy. The prevalence of hypertrophy was 25%. Multivariate analysis showed that hypertension and acute rejection history were the risk factors that resulted in left ventricular hypertrophy. It is concluded that the left ventricular remodeling occurs following cardiac transplantation at an early stage and the incidence of left ventricular hypertrophy increases with survival time. In this study, the one-year prevalence of left ventricular hypertrophy was 25% after surgery. Hypertension and acute rejection history are risk factors that can predict the left ventricular hypertrophy.