Jing-Yan Han

Tumour necrosis factor α signalling through activation of Kupffer cells plays an essential role in liver fibrosis of non-alcoholic steatohepatitis in mice

Background: While tumour necrosis factor α (TNF-α) appears to be associated with the development of non-alcoholic steatohepatitis (NASH), its precise role in the pathogenesis of NASH is not well understood. Methods: Male mice deficient in both TNF receptors 1 (TNFR1) and 2 (TNFR2) (TNFRDKO mice) and wild-type mice were fed a methionine and choline deficient (MCD) diet or a control diet for eight weeks, maintaining isoenergetic intake. Results: MCD dietary feeding of TNFRDKO mice for eight weeks resulted in attenuated liver steatosis and fibrosis compared with control wild-type mice. In the liver, the number of activated hepatic Kupffer cells recruited was significantly decreased in TNFRDKO mice after MCD dietary feeding. In addition, hepatic induction of TNF-α, vascular cell adhesion molecule 1, and intracellular adhesion molecule 1 was significantly suppressed in TNFRDKO mice. While in control animals MCD dietary feeding dramatically increased mRNA expression of tissue inhibitor of metalloproteinase 1 (TIMP-1) in both whole liver and hepatic stellate cells, concomitant with enhanced activation of hepatic stellate cells, both factors were significantly lower in TNFRDKO mice. In primary cultures, TNF-α administration enhanced TIMP-1 mRNA expression in activated hepatic stellate cells and suppressed apoptotic induction in activated hepatic stellate cells. Inhibition of TNF induced TIMP-1 upregulation by TIMP-1 specific siRNA reversed the apoptotic suppression seen in hepatic stellate cells. Conclusions: Enhancement of the TNF-α/TNFR mediated signalling pathway via activation of Kupffer cells in an autocrine or paracrine manner may be critically involved in the pathogenesis of liver fibrosis in this NASH animal model.

Early inhibition of HIF-1α with small interfering RNA reduces ischemic–reperfused brain injury in rats

Hypoxia-inducible factor-1 (HIF-1) plays an essential role in cerebral ischemia as a proapoptotic factor. We hypothesized that HIF-1alpha siRNA can protect the brain from ischemic damage by inhibiting HIF-1alpha induced apoptotic pathway at the RNA level in a rat focal ischemic model. Results showed that treatment with HIF-1alpha siRNA reduced the infarct volume, decreased mortality, improved neurological deficits and reduced Evans blue extravasation. The expression of HIF-1alpha mRNA (Real-Time PCR) and protein were significantly silenced and the immunohistochemistry and Western blot revealed the suppression of HIF-1alpha, VEGF, p53 and Caspase-3. Double fluorescence labeling showed HIF-1alpha positive immunoreactive materials were partly colocalized with NeuN, p53 and Caspase-3 in the injured cerebral cortex. This study showed that HIF-1alpha siRNA may protect the ischemic-reperfused neurons in vivo via inhibition of HIF-1alpha, its downstream VEGF and other apoptotic-related proteins such as p53 and Caspase-3 and may have potentials for the early treatment of ischemic cerebral stroke.

Multiple effects of 2ME2 and D609 on the cortical expression of HIF-1α and apoptotic genes in a middle cerebral artery occlusion-induced focal ischemia rat model

Despite 2‐methoxyestradiol (2ME2) and tricyclodecan‐9‐yl‐xanthogenate (D609) having multiple effects on cancer cells, mechanistically, both of them down‐regulate hypoxia‐inducible factor‐1α (HIF‐1α) and vascular endothelial growth factor (VEGF). We hypothesize HIF‐1α plays an essential role in cerebral ischemia as a pro‐apoptosis regulator; 2ME2 and D609 decrease the levels of HIF‐1α and VEGF, that might contribute to protecting brain from ischemia injury. A total of 102 male Sprague–Dawley rats were split into five groups: sham, middle cerebral artery occlusion (MCAO), MCAO + dimethyl sulfoxide, MCAO + 2ME2, and MCAO + D609. 2ME2 and D609 were injected intraperitoneally 1 h after reperfusion. Rats were killed at 24 h and 7 days. At 24 h, 2ME2 and D609 reduce the levels of HIF‐1α and VEGF (enzyme‐linked immunosorbent assay), depress the expression of HIF‐1α, VEGF, BCL2/adenovirus E1B 19 kDa interacting protein 3 (BNIP3) and cleaved caspase 3 (western blot and immunohistochemistry) in the brain infarct area. Double fluorescence labeling shows HIF‐1α positive immunoreactive materials are co‐localized with BNIP3 and terminal deoxynucleotidyl transferase biotin‐dUTP nick end labeling inside the nuclei of neurons. At 7 days, 2ME2 and D609 reduce the infarct volume (2,3,7‐triphenyltetrazolium chloride) and blood–brain barrier extravasation, decrease the mortality and improve the neurological deficits. In conclusion, 2ME2 and D609 are powerful agents to protect brain from cerebral ischemic injury by inhibiting HIF‐1α expression, attenuating the superfluous expression of VEGF to avoid blood–brain barrier disruption and suppressing neuronal apoptosis via BNIP3 pathway.

Therapeutic application of gene silencing MMP-9 in a middle cerebral artery occlusion-induced focal ischemia rat model.

RNA interference appears to have a great potential not only as an in vitro target validation, but also as a novel therapeutic strategy based on the highly specific and efficient silencing of a target gene. We hypothesize that MMP-9 siRNA can be effective as an MMP-9 protein inhibitor in a rat focal ischemia model. Male Sprague-Dawley rats (156) were subjected to 2 h of middle cerebral artery occlusion (by using the suture insertion method) followed by 24 h of reperfusion. In the treatment group, 5 microl MMP-9 siRNA was administrated by intracerebroventricular injection within 60 min after 2 h of focal ischemia. The siRNA transfection was demonstrated by fluorescence conjugated siRNA. Treatment with MMP-9 siRNA produced a significant reduction in the cerebral infarction volume, brain water content, mortality rate and accompanying neurological deficits. The followings were recorded: Evans blue and IgG extravasation were reduced; the expression of MMP-9 mRNA and protein were significantly silenced; and immunohistochemistry and Western blot analysis revealed that the expression of MMP-9 and VEGF were reduced while occludin and collagen-IV were up-regulated in brain tissues. Our findings provide evidence that a liposomal formulation of siRNA might be used in vivo to silence the MMP-9 gene and could potentially serve as an important therapeutic alternative in patients with cerebral ischemia.

Enhanced levels of chemiluminescence and platelet activating factor in urease-positive gastric ulcers

Helicobacter pylori are believed to play an important role in the formation of gastric ulcer in a syndrome characterized by a high urease activity. On the other hand, the production of oxygen radicals and platelet activating factor (PAF) is enhanced in gastric ulcers. The present study is designed to investigate the relationship between the different aspects of gastric mucosal injury, urease activity, oxygen radical production, and PAF content in gastric specimens. Biopsy specimens taken from 35 gastric ulcer patients were studied. Urease activity was detected by a rapid urease test (CLO). Oxygen radical production was measured as a value of luminol-dependent chemiluminescence (ChL) and PAF content was determined by radioimmunoassay in the biopsy samples. The CLO-positive rate was significantly higher in the gastric ulcer group in comparison with that in controls. ChL values and PAF content were significantly increased in gastric ulcers, especially in CLO-positive specimens. The CLO-positive rate, ChL values, and PAF content were also found to be increased at a distant site beyond the ulcer lesions. During the course of macroscopic ulcer healing of CLO-positive cases, the CLO positive level and the ChL values were not significantly decreased, although PAF content was significantly lower. Enhanced oxygen radical and PAF production were observed not only in the ulcer region but also at a distant site from the ulcer in the urease-positive gastric mucosa. The persistent enhancement of ChL values during the healing stage of urease-positive gastric ulcers suggests its involvement in the recurrence of gastric ulcers.

Lentivirus-mediated transfer of MMP-9 shRNA provides neuroprotection following focal ischemic brain injury in rats.

Various studies on focal cerebral ischemic models have implicated the direct activation and expression of matrix metalloproteinases (MMPs), especially MMP-9, as a key orchestrator of blood-brain barrier (BBB) disruption. Moreover, studies have shown that MMP-9 siRNA can protect the BBB from ischemia/reperfusion injury. In the present study, we investigated the neuroprotective role of a lentivirus vector-mediated mmp-9shRNA following focal cerebral ischemia--specifically assessing whether LV-mmp9shRNA silencing of MMP-9 mRNA could ameliorate BBB disruption and in turn reduce vascular permeability, neuronal cell death, and neurobehavioral deficits. Treatment was given 2 weeks prior to surgery using a lentivirus-mediated vector. Surgery was conducted using the established middle cerebral artery occlusion (MCAO) model in rats, while outcomes were measured 24 h after injury. Our results demonstrated a significant reduction in brain infarction volume, brain water content, and neurobehavioral deficits following LV-mmp9shRNA treatment. Additionally, Evans blue and IgG extravasation were reduced, MMP-9 mRNA expression was silenced, and Western blot analysis revealed a decreased expression of MMP-9 and VEGF with an increased expression of occludin and collagen IV in brain tissues. This suggests that successful delivery of LV-mmp9shRNA may ameliorate ischemic brain injury by preserving structural integrity and improving functional outcome.

Cardiotonic pills, a compound Chinese medicine, protects ischemia-reperfusion-induced microcirculatory disturbance and myocardial damage in rats

Cardiotonic pills (CP) is a compound Chinese medicine widely used in China, as well as other countries, for the treatment of cardiovascular disease. However, limited data are available regarding the mechanism of action of CP on myocardial function during ischemia-reperfusion (I/R) injury. In this study, we examined the effect of CP on I/R-induced coronary microcirculatory disturbance and myocardial damage. Male Sprague-Dawley rats were subjected to left coronary anterior descending branch occlusion for 30 min followed by reperfusion with or without pretreatment with CP (0.1, 0.4, or 0.8 g/kg). Coronary blood flow, vascular diameter, velocity of red blood cells, and albumin leakage were evaluated in vivo after reperfusion. Neutrophil expression of CD18, malondialdehyde, inhibitor-kappaBalpha, myocardial infarction, endothelial expression of intercellular adhesion molecule 1, apoptosis-related proteins, and histological and ultrastructural evidence of myocardial damage were assessed after reperfusion. Pretreatment with CP (0.8 g/kg) significantly attenuated the I/R-induced myocardial microcirculatory disturbance, including decreased coronary blood flow and red blood cell velocity in arterioles, increased expression of CD18 on neutrophils and intercellular adhesion molecule 1 on endothelial cells, and albumin leakage from venules. In addition, the drug significantly ameliorated the I/R-induced myocardial damage and apoptosis indicated by increased malondialdehyde, infarct size, myocardial ultrastructural changes, terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling-positive myocardial cells, inhibitor-kappaBalpha degradation, and expression of Bcl-2, Bax, and caspase-3 in myocardial tissues. The results provide evidence for the potential role of CP in preventing microcirculatory disturbance and myocardial damage following I/R injury.

Potential of 3, 4-Dihydroxy-phenyl Lactic Acid for Ameliorating Ischemia-Reperfusion-Induced Microvascular Disturbance in Rat Mesentery

This study intended to examine the effect of 3,4-dihydroxy-phenyl lactic acid (DLA), a major ingredient of Salvia miltiorrhiza, on ischemia-reperfusion (I/R)-induced rat mesenteric microcirculatory injury. DLA (5 mg.kg(-1).h(-1)), superoxide dismutase (SOD, 12,000 U.kg(-1).h(-1)), or catalase (CAT, 20 mg/kg) was continuously infused either starting from 10 min before the ischemia or 10 min after the initiation of reperfusion. The venule diameter, number of adherent leukocytes, FITC-albumin leakage, dihydrorhodamine 123 fluorescence, and mast cell degranulation were determined using an intravital microscope. The production of hydrogen peroxide (H(2)O(2)) and the expression of adhesion molecules CD11b/CD18 in neutrophils were evaluated by in vitro experiments. The results showed that pretreatment with DLA significantly reduced peroxide production in and leukocyte adhesion to venular wall, albumin leakage, and mast cell degranulation induced by I/R. The DLA posttreatment exerted an ameliorating effect on I/R-induced disorders as well, characterized by inhibiting further increase in peroxide production in venular wall and albumin leakage and diminishing the number of leukocytes that had adhered to the venular wall. In vitro experiments revealed that treatment with DLA significantly attenuated TNF-alpha plus fMLP-evoked production of H(2)O(2) and the H(2)O(2)-elicited expression of CD11b/CD18 on neutrophils. SOD and CAT manifested similarly but with the exception that either SOD or CAT were unable to retrieve the adherent leukocytes if administrated after initiation of reperfusion and to depress the H(2)O(2)-induced expression of CD11b/CD18 on neutrophils. It is concluded that DLA protects from and ameliorates the I/R-induced microcirculatory disturbance by interfering with both peroxide production and adhesion molecule expression.

THE ANTIOXIDANT CEREBRALCARE GRANULE ATTENUATES CEREBRAL MICROCIRCULATORY DISTURBANCE DURING ISCHEMIA-REPERFUSION INJURY

Cerebralcare Granule (CG) is a compound Chinese medicine used for treatment of headache and dizziness associated with cerebrovascular diseases. To clarify the mechanism underlying the clinical outcome of CG, this study investigated the effects of CG on the structure and function of cerebral microvasculature during I/R injury. A total of 138 Mongolian gerbils were included and divided into four groups, each composed of 36 or 30 animals, for evaluating various parameters of concern. A skull window was prepared for microcirculatory observation in animals, which were subjected to I/R with or without pretreatment with CG (0.4 or 0.8 g/kg). The velocity of red blood cells in the venules was observed by a high-speed video camera system, along with intravital confocal microscopic measurements of microvascular diameters, adherent leukocytes, and albumin leakage in the brain cortex. Changes in the fluorescence intensity of dihydrorhodamine 123 in cerebral microvessels and malondialdehyde level in the cortex were measured. The ultrastructure of the microvessels in the cerebral cortex was analyzed using both transmission and scanning electron microscopy. In addition, cerebral blood flow was monitored using the laser Doppler imaging technique. Pretreatment with CG (0.4 or 0.8 g/kg) significantly alleviated I/R injury-induced disorders in cerebral microvasculature, as evidenced by the data observed at 60 min of reperfusion wherein the values in CG (0.4 g/kg) pretreatment group, CG (0.8 g/kg) pretreatment group, and I/R group were 2.43 +/- 0.24, 2.28 +/- 0.18, and 6.00 +/- 0.35 for leukocyte adhesion, 2.51 +/- 0.40, 2.33 +/- 0.29, and 4.77 +/- 0.24 for albumin leakage, 7.06 +/- 0.81, 5.93 +/- 0.42, and 28.38 +/- 2.70 for dihydrorhodamine 123 fluorescence intensity in cerebral microvessels, 16.35 +/- 0.52, 14.34 +/- 0.68, and 21.46 +/- 0.71 for malondialdehyde level in the cortex, and 0.43 +/- 0.07, 0.46 +/- 0.02, and 0.17 +/- 0.08 for cerebral blood flow, respectively. I/R injury-elicited ultrastructural alterations in microvessels in cerebral cortex were also mitigated impressively by CG administration, manifested as attenuation of the reduced number of opening capillaries and the altered fine structures in endothelium, which were characterized by rough inner surface, increased intracellular vesicles, hypertrophy of digitations of intercellular contact, and swollen perivascular astroglial processes. Cerebralcare Granule is able to attenuate I/R injury-induced functional and structural changes in microvessels in the cerebral cortex of gerbils, an ability that is most likely correlated with its antioxidant potential.

Cerebralcare Granule® attenuates blood–brain barrier disruption after middle cerebral artery occlusion in rats

Disruption of blood-brain barrier (BBB) and subsequent edema are major contributors to the pathogenesis of ischemic stroke, for which the current clinical therapy remains unsatisfied. Cerebralcare Granule® (CG) is a compound Chinese medicine widely used in China for treatment of cerebrovascular diseases. CG has been demonstrated efficacy in attenuating the cerebral microcirculatory disturbance and hippocampal neuron injury following global cerebral ischemia. However, the effects of CG on BBB disruption following cerebral ischemia have not been investigated. In this study, we examined the therapeutic effect of CG on the BBB disruption in a focal cerebral ischemia/reperfusion (I/R) rat model. Male Sprague-Dawley rats (250 to 300 g) were subjected to 1h middle cerebral artery occlusion (MCAO). CG (0.4 g/kg or 0.8 g/kg) was administrated orally 3h after reperfusion for the first time and then once daily up to 6 days. The results showed that Evans blue extravasation, brain water content, albumin leakage, infarction volume and neurological deficits increased in MCAO model rats, and were attenuated significantly by CG treatment. T2-weighted MRI and electron microscopy further confirmed the brain edema reduction in CG-treated rats. Treatment with CG improved cerebral blood flow (CBF). Western blot analysis and confocal microscopy showed that the tight junction proteins claudin-5, JAM-1, occludin and zonula occluden-1 between endothelial cells were significantly degradated, but the protein expression of caveolin-1, the principal marker of caveolae in endothelial cells, increased after ischemia, all of which were alleviated by CG treatment. In conclusion, the post-treatment with CG significantly reduced BBB permeability and brain edema, which were correlated with preventing the degradation of the tight junction proteins and inhibiting the expression of caveolin-1 in the endothelial cells. These findings provide a novel approach to the treatment of ischemic stroke.