Heatstroke Induce Microcirculation Dysfunction Of The Liver By Activating SEC In A Rat Model

Objectives1.To observed the variation of liver injury in severe heat stroke rats.2. To investigate the structure and functional injury of sinusoidal endothelial cells in liver injury during severe heat stroke rats.3.To explore the the tissue damage, inflammation injury, microcirculation change and other aspects of the liver after Xuebijing pretreatment.Methods1. A severe heat stroke model of rats was established, collect the specimens when core temperature to target.36male adult Wista rats with SPF which weighing approximately between250-350g were randomly divided into six groups:A. Sham group,6rats, in the first90minutes after the start of the experiment and were sacrificed to collect specimens; B.39℃group,6rats, when the center of the modeling process, the temperature reached39℃rats were sacrificed immediately and collect specimens; C.42℃group,6rats, when the core temperature of rats reached42℃immediately collected specimens; D. severe heatstroke group (HS group),6rats, collection of specimens were begin at the time that HS model was built successfully; E.Xuebijing pretreatment group (XBJ group),6rats, rats were pretreatment by intravenous injection of Xuebijing injection in the pre-48hours before the model was built, specimens were collection immediately after HS; F. Saline pretreatment and HS group (saline group), rats were pretreatment by intravenous injection of saline as the same dozen of XBJ in the same time, before the model was built, specimens were collection immediately after HS.2.Liver enzymes, histology change, ultrastructural changes and apoptosis changes of the liver were measured during the gradient thermal treatment in each group2.1Serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) concentrations were measured.2.2Histological changes of the liver were observed by HE staining in each group.2.3Analysis cell apoptosis of the liver by TUNNEL method.3. Observe the injury of SEC, including changes in the concentration of circulating blood of SCE injury markers and vasomotor substances, changes in the ultrastructure of the SEC, the expression of the relevant factors.3.1Serum concentration of rats SEC injury markers, including thrombomodulin (TM), hyaluronic acid (HA),(vWF) were measured.3.2Ultrastructural changes of SEC were observed in each group under the TEM.3.3Immunohistochemistry staining was used to detect the expression of vWF, tissue factor (TF), changes in the TM on SEC in each group.3.4The mRNA expression of adhesion molecules (ICAM-1), interleukin-6(IL-6), and TF were measured by RT-PCR.3.5Serum concentration of endothelin-1(ET-1) and nitric oxide (NO) were measured.Results1. Severe liver injury was displayed from42℃group, and as the temperature gradient increases, degree of injury increase in, and injury in severe heat stroke group was most obvious.1.1HS rats serum concentrations of AST and ALT in HS group was significantly higher than the control group, XBJ group is lower than HS group(P<0.05);1.2Liver pathology damage were found in the42℃group especially HS group, mainly display around the liver sinus area, but XBJ group show no damage.1.3Apoptosis of liver cells increase significantly when core temperature reached42℃, HS group was significantly (P<0.05), and apoptotic cells were mainly concentrated in sinusoidal periphery, Apoptosis of liver cells in the XBJ group were less.2HS induced structural and functional damage of SEC 2.1heatstroke induced changes in the concentration of serum SEC injury markers:2.1.1Concentration of sTM were decreased in HS:Compared to the SHAM group,39℃group increased but42℃group and HS group decreased significantly, XBJ group were higher than HS group (p<0.05);2.1.2Serum concentration of HA increased during heatstress:compared to the control group42℃group and HS group increased significantly, XBJ group were lower (p<0.05);2.2.3Serum concentration of vWF were increased in HS:Serum concentrations of vWF began increased slowly at39℃group,42℃group and HS group was increased significantly, and HS group (p<0.05) higher than42℃group, but XBJ group were lower, the differences was significantly;2.2.4Imbalance of SEC-drived vascular vasomotor substance concentration in HS:ET-1concentrations ranging from39℃group increased gradually, HS group increased significantly, XBJ group lower than HS group(p<0.05); while concentration of NO in SHAM group and39℃show no significant difference (P<0.05),42℃group concentration decreased significantly, HS group concentration decreased significantly, and XBJ group were higher than HS group and HS group(P<0.05);2.2Ultrastructural changes of SEC in HS:the SHAM group and39℃show no significant ultrastructural changes;42℃group:SEC begin to swelling obvious, the structural integrity of the structure of cell damage significantly, local see vacuolar degeneration, swelling and endoplasmic reticulum blurred, sinusoidal dilatation, congestion significantly, local focal hemorrhage lesion; HS group:SEC significantly reduced shrinkage deformation of the nucleus, sinusoidal dilatation, congestion increased;XBJ group:the changes were reduced.2.3Endothelial-drived markers measured by immunohistochemical staining in HS:the SHAM group and39℃group showed no significant expression of TF and vWF,42℃and HS group sinusoidal surrounding TF and vWF expression was obvious, and the XBJ group express less than HS group; while42℃group and HS group sinusoidal surrounding TM expression significantly reduced significantly, and the XBJ group express mildly, the COD value analysis showed significant differences P<0.05)3IL-6, ICAM-1, TF mRNA expression in the liver tissue:the ICAM-1mRNA and TF mRNA of HS group was increased significantly, and IL-6at42"C group and HS group expression increased significantly, the data difference was significant (P<0.05)ConclusionSignificantly liver injury were present during the course of gradient heat stress, microcirculation dysfunction was display around the liver sinus local area, structural damage and functional impairment of SEC were found during the gradient thermal stress process, and coagulation factor such as TM, TF, vWF were expression, and the vasomotor material concentration of ET-1and NO also express imbalancecaused which can results in local microcirculation disorder furtherly contribute to the liver injury. Xuebijing pretreatment can alleviate the structural damage and functional impairment of SEC and the microcirculation dysfunction of liver in HS.