Abnormally modified tau and hypoxic-ischemic brain damage

Tau is the most abundant microtubule-associated protein in the brain. If tau protein lost the normal function, the toxic effect should be showed and plays an important role in various central nervous system lesions. Hypoxic-ischemic encephalopathy (HIE) is an important cause of mortality in the neonatal period and it is mainly characterized by neurological deficits such as cognitive limitations. However, the mechanism still needs further study, and the underlying relationship between tau protein and HIE lacks direct evidence. Some recent clinical study reported that tau protein expression elevated in the serum of asphyxia children and had a high correlation with behavior deficient. In this review, we focus on 3 key points to provide new insights to understand the tau protein-related pathogenesis of HIE as followed: (1) tau protein and its phosphorylation change during central nervous system development; (2) comparison of tau protein expression in developing brain and adult brain under some neurological disorders; (3) potential pathological change of tau in HIE related pathological conditions, such as dysmyelination, inflammation response and glutamate metabolism.     

Protective effect of deferoxamine on hypoxic-ischemic encephalopathy in neonatal rat

AIM:To investigate the possible mechanism of deferoxamine on angiogenesis in rat hypoxic-ischemic encephalopathy (HIE). METHODS:SD rats (7 days of age) were used to make HIE model. Model group and treatment group were injected with deferoxamine or normal saline alone 24 hours before hypoxic-ischemic insult. Rats were sacrificed at 1,3,7 or 14 days after hypoxic-ischemic insult. Brain capillary density index (BCDI),the number of proliferating capillary,brain water content and extent of brain atrophy were determined. The expression of vascular endothelial growth factor (VEGF) and hypoxia-inducible factor-1α(HIF-1α) mRNA was measured. RESULTS:Early water content and late atrophic ratio of the left brain were significantly improved in the treatment group compared to model group (P<0.01). The number of proliferating capillary in the treatment group was significantly higher than that in the model group ［(2.01±0.31)/HPF vs　(0.90±0.25)/HPF,P<0.01］. Deferoxamine markedly up-regulated the expression of VEGF and HIF-1α mRNA in the brain ［VEGF at 12 h: (1.41±0.07) vs (1.10±.15),P<0.05; HIF-1α at 12 h: (1.49±0.12) vs (1.11±0.16),P<0.05］.CONCLUSION:Deferoxamine may promote angiogenesis and attenuate hypoxic-ischemic induced brain injury via up-regulation of HIF-1α and VEGF expression.     

Adenosine A2A receptor antagonist SCH58261 attenuates hypoxic-ischemic brain damage in a fetal rabbit model

AIM: To study the effect of adenosine A_2A receptor antagonist SCH58261 on hypoxic-ischemic brain damage (HIBD) in a mature fetal rabbit model.METHODS: Pregnant New Zealand white rabbits at gestational day 29 were selected and were randomly divided into sham-operated group, hypoxic-ischemic group, SCH58261 0.04 mg/kg group, SCH58261 0.12 mg/kg group and DMSO group. The intrauterine rabbit HIBD model was established. All pregnant rabbits were subjected to cesarean section 24 h after the sham operation or experimental procedure to induce hypoxic-ischemic injury in the fetus. The survival neonatal rabbits were kept in a neonatal incubator at 35℃. The general conditions of the newborn rabbits were recorded. The degree of neurobehavioral damage in the newborn rabbits was estimated by a neurobehavioral scoring protocol. The concentration of SCH58261 in the serum of pregnant rabbits, the serum of neonatal rabbits and the brain tissues of neonatal rabbits was measured by mass spectrometry. The mRNA expression of Bcl-2/Bax and protein levels of p-P38 mitogen-activated protein kinase (MAPK) in the cortex, hippocampus and striatum area in the brain of the neonatal rabbits were determined by real-time PCR and Western blot. RESULTS: SCH58261 was detected in the serum and brain tissues of the newborn rabbits. The SCH58261 concentration was approximately 40 μg/L in the brain tissue of the newborn rabbits. The mRNA expression of Bcl-2 in the cortex, hippocampus and striatum of brain tissues in SCH58261 0.04 mg/kg group and SCH58261 0.12 mg/kg group was higher, and the mRNA expression of Bax was lower than those in HI group (P<0.05). The protein level of p-P38 MAPK in the cortex, hippocampus and striatum of brain tissues was reduced in SCH58261 0.04 mg/kg group and SCH58261 0.12 mg/kg group compared with HI group (P<0.05). The protein level of p-P38 MAPK in SCH58261 0.12 mg/kg group was a little lower than that in SCH58261 0.04 mg/kg group (P<0.05). CONCLUSION: Adenosine A_2A receptor antagonist SCH58261 attenuates hypoxia-ischemia induced neonatal brain injury by blocking adenosine A_2A receptor, subsequently inhibiting p-P38 MAPK phosphorylation to reduce neuronal apoptosis.     

Research progress in apoptosis and hypoxic-ischemic brain damage

Apoptosis is one of the most important causes, which results in the central neuronal system complication in hypoxic-ischemic brain damage (HIBD). Apoptosis occurs in the developing brain more than in the developed brain. Apoptosis can last several weeks and may be inverted its pathology by appropriate therapy. Caspase inhibitor, neurotrophic factors, anti-apoptosis gene Bcl-2, mild hypothermia,and early intervention play important roles in promoting neuronal cell survival and preventing from apoptosis through different mechanisms. It may be a new way for rehabilitation of HIBD.     

Expression of p-p38 MAPK in partial cerebral tissues after hypoxic-ischemic brain damage in neonatal A2AR knockout mice

AIM： To study the expression of p-p38 MAPK in partial cerebral tissues after hypoxic-ischemic brain damage (HIBD) in the neonatal adenosine A2A receptor knockout (A2AR-/-) mice. METHODS：Base on the modified Rice method, the model of HIBD was established. The total 64 C57/BL6 neonatal mice (7 days old) of A2AR-/-(KO) and corresponding wild type (A2AR+/+, WT) were randomized into sham-operated group and model group. The mice in model group were divided into 3 subgroups： 1 d after HIBD, 3 d after HIBD and 7 d after HIBD (n=8 for each group). The cortex and hippocampal CA1 region were used as the study areas. The neuronal apoptosis was detected using TUNEL assay combined with Nissl staining. The expression of p-p38 MAPK and activated caspase-3 was determined by the method of immunohistochemistry. The KO mice and WT mice were also taken from sham-operated group (SKO and SWT, n=10) and model group (MKO and MWT, n=30) 1 d after HIBD to assess the early neurological behavior. RESULTS：The apoptotic neurons, activated caspase-3 and p-p38 MAPK increased after HIBD and peaked at 1 d after HIBD in the cortex and the hippocampal CA1 region. The apoptotic neurons and the expression of activated caspase-3 in KO mice were significantly higher than those in WT mice at the same time point after HIBD. The expression level of p-p38 MAPK in KO mice were significantly higher than that in WT mice at 1 d and 3 d after HIBD. The expression of activated caspase-3 was positively correlated with the expression of p-p38 MAPK in neonatal mice after HIBD (in the cortex：r=0.957, P<0.01; in the hippocampal CA1 region： r=0.939, P<0.01). CONCLUSION：p-p38 MAPK might be involved in the aggravated neuron apoptosis and brain damage induced by A2AR knockout after neonatal HIBO.     

Effect of hyperbaric oxygen on NSCs in the neonatal rat with hypoxic-ischemic brain damage

AIM: To discuss the mechanism of hyperbaric oxygen (HBO) therapy by assessing the changes of neural stem cells (NSCs), after hypoxic-ischemic brain damage (HIBD) in neonatal rats. METHODS: Seven-day-old SD rat pups were randomly divided into 4 groups: control group (CON, n=16), HIBD group (n=16), hyperbaric air group (HBA, n=16), and HBO group (n=16). The HIBD model was produced by permanent occlusion of left common carotid artery and was exposed to a mixture of 8% oxygen and 92% nitrogen for 2 h (at 37 ℃). HBA and HBO treatment was administered by placing pups in a chamber (2 ATA for 1 h) 1 h after hypoxia exposure and performed once daily for 7 days. BrdU immunohistochemistry was used to assess how the insult had affected NSCs in the SVZ of the lateral ventricle and DG of the hippocampus. The NSCs from the ipsilateral SVZs were isolated at 3 weeks recovery from hypoxia-ischemia (HI). The number of spheres was then counted as an index of the number of NSCs residing within the SVZ. RESULTS: At 3 week survival, the SVZ of HIBD group was smaller and markedly less cellular than control group. BrdU-positive cells were dramatically decreased in the SVZ and DG of the affected hemisphere (P<0.01) and by in vitro cell culture it contained less NSCs in the SVZ of the affected hemisphere, too. HBO resulted in weaker proliferation of BrdU-positive cells in the SVZ and DG. CONCLUSION: Hypoxia-ischemia depletes the rat NSCs in SVZ and DG, HBO can weak this depletion, but HBA has no effect.     

Protective effect of atorvastatin on blood brain barrier in rats with focal cerebral ischemia-reperfusion injury

AIM: To explore the protective effects of atorvastatin on blood brain barrier(BBB) in cerebral ischemia-reperfusion(IR) injury and the potential mechanisms involved. METHODS: SD rats were divided into sham group, IR group and atorvastain group. Intraluminal suture method was used to establish cerebral IR model, and the ischemic brain was reperfused for 72 h after the occlusion. The rats in atorvastatin group were administered with atorvastatin(20 mg·kg^-1·d^-1) by gavage once a day for 3 consecutive days after operation. At 72 h after reperfusion, neurological function scores, the water content of the brain tissue, Evans blue(EB) content of ischemic hemisphere, the expression of tight junction(TJ)-associated protein occludin and inflammation factor phosphatidylinositiol 3-kinase-p110 gamma(PI3K-p110γ) were tested and analyzed. RESULTS: In IR group, the rats showed elevated neurological function scores(P<0.01), brain tissue water content(P<0.01) and EB content(P<0.01), accompanied with the down-regulation of occludin expression(P<0.01) and up-regulation of PI3K-p110γ(P<0.01) at 72 h after reperfusion. Compared with IR group, decreased brain edema(P<0.01) and EB leakage(P<0.01) were observed in atorvastatin group, accompanied with increased occludin expression(P<0.01) and decreased PI3K-p110γ expression(P<0.01). However, no statistical difference of the neurological function scores between the 2 groups was observed. CONCLUSION: Atorvastain attenuates cerebral IR injury, which may be associated with the inhibition of inflammatory reactions and the up-regulation of TJ-asso-ciated proteins to maintain the stability of BBB.     

Role of oxytocin in neonatal rat hippocampal neurons after hypoxic-ischemic injury

AIM: To investigate whether oxytocin has neuroprotective effects on hippocampal CA1 pyramidal neurons from neonatal rats exposed to hypoxic-ischemic brain injury and the underlying mechanisms. METHODS: An in vitro model of hypoxic-ischemic injury was used by exposing the brain slices to oxygen-glucose deprivation (OGD) solution. Acute dissociated brain slices (6~8 slices per rat) from 8 Sprague-Dawely rats of 7~10 d old were used. The slices were randomly divided into 4 groups:control group, OGD 20 min group, OGD 40 min group and OGD+oxytocin group. The effect of oxytocin on neuronal death was evaluated by TO-PRO-3 staining. Fresh brain slices from other 20 neonatal rats were divided into OGD group, OGD+oxytocin group, OGD+dVOT (oxytocin receptor antagonist)+oxytocin group, and OGD+bicucuclline (GABA_A receptor antagonist)+oxytocin group. The onset of anoxic depolarization in the hippocampal neurons treated with different drugs was recorded by whole-cell patch-clamp techniques. RESULTS: The results of TO-PRO-3 staining showed that neuronal deaths in hippocampal CA1 area were increased over the prolonged OGD time. Oxytocin significantly reduced the hypoxic-ischemic deaths. Oxytocin dramatically prolonged the onset time of anoxic depolarization after the application of OGD solution. Both dVOT and bicuculline blocked this effect. CONCLUSION: Oxytocin plays a neuroprotective role in neonatal rat hippocampal CA1 pyramidal neurons by enhancing the inhibitory synaptic transmission via oxytocin receptors. Therefore, oxytocin is useful as a candidate for neuroprotective treatment after neonatal hypoxic-ischemic brain injury.     

Protective effects of taurine on LPS-induced myocardial damage in rats

AIM: To investigate the effects of taurine on lipopolysaccharide (LPS)-induced myocardial damage in rats. METHODS: Healthy male SD rats (n=30) were randomly divided into control group (CON), LPS model group (LPS) and taurine treatment group (TAU). The rats in CON group and LPS group were intravenously injected with normal saline, and the rats in TAU group were injected with taurine (100 mg/kg). After 2 h, the rats in LPS group and TAU group were intraperitoneally injected with LPS at 10 mg/kg, and the rats in CON group were injected with normal saline. Six hours after injection of LPS, the blood samples were collected for determination of superoxide dismutase (SOD) activity, malondialdehyde (MDA) content, and tumor necrosis factor α (TNF-α) and interleukin-6 (IL-6) levels. The myocardial tissues were processed for histological examination and the analysis of Western blot. RESULTS: Compared with CON group, LPS significantly reduced SOD activity in the serum and heme oxygenase 1 (HO-1) protein expression in the myocardial tissues, increased the serum content of MDA and levels of TNF-α and IL-6. LPS also significantly elevated the levels of TNF-α and IL-6, and up-regulated the cyclooxygenase-2 (COX-2) expression and phosphorylation of nuclear factor kappa B (NF-κB) in the myocardial tissues. Taurine pretreatment significantly elevated SOD activity and HO-1 protein expression level, decreased the levels of COX-2, TNF-α, IL-6 and phosphorylated NF-κB. Histological observation showed that taurine reduced inflammatory response in the myocardial tissue. CONCLUSION: Taurine attenuates LPS-induced myocardial damage in rats. The beneficial effects of taurine may be associated with its reduction of p-NF-κB/COX-2 signaling by activation of HO-1/CO.     

Establishment of intrauterine hypoxic-ischemic brain damage model in near term fetal rabbits

AIM: To establish intrauterine hypoxic-ischemic brain damage (HIBD) model in near term fetal rabbits at 29 d gestation age for the investigation of the pathogenesis and treatment of newborn HIBD. METHODS: Twenty-four pregnant New Zealand white rabbits at 29th gestational day were chosen for this project. Under combined general anesthesia and spinal anesthesia, a 4F Fogarty arterial embolectomy catheter was introduced into the left femoral artery. The blood supply of uterus in experiment group was blocked by inflating the catheter balloon with 0.3 mL saline for 20 min, 25 min, 28 min, 30 min and 40 min (n=4 for each experimental time group). The catheter balloon was not inflated in control group (n=4). All pregnant rabbits were subject to cesarean section 24 h after the experimental procedure to induce hypoxia-ischemia to the fetus. The general conditions of the newborn rabbits were recorded, and the neurobehavioral damage and histology of the brain tissue were assessed. RESULTS: During the entire procedure, the pregnant rabbits had stable vital signs, no hypoxia happened,and had a good tolerance to the anesthesia program. When the balloon was inflated, the pulses of right femoral artery disappeared and the right leg blood pressure became non-detectable in experimental groups. In contrast, no fluctuation of the right leg blood pressure in control group (P>0.05) was observed. Intrauterine hypoxia-ischemia caused neonatal and fetal rabbit death, neurobehavioral damage and brain cell death. When the balloon was inflated for 20 min, all fetal rabbits were alive and had no obvious neurologic damage. For 25~28 min, the stillbirth rates were 12.9% and 40.6%, respectively, while the live neonatal rabbits manifested neurobehavioral damage, edema neural cells, activated microglia cells and apoptotic brain cells. When blocking time beyond 30 min, above 80% fetal rabbits died. CONCLUSION: Continuous blockage of uterine blood supply in pregnant rabbits causes neonatal rabbit death, neurobehavioral damage and brain cell death. Different blocking time arouses different levels of brain damage. Continuous blockage of uterine blood supply for 25-28 min can establish fetal generalize hypoxic-ischemic brain damage rabbit model, which is a good animal model for the investigation of newborn HIBD.     

Protective effect of ethyl pyruvate against LPS-induced acute lung injury in dogs with septic shock

AIM:To investigate the effect of ethyl pyruvate (EP) on acute lung injury in dogs with septic shock.METHODS:Twenty dogs with septic shock induced by lipopolysaccharide (LPS) were randomly divided into two groups:dog received placebo (Ringers solution; control group, n=8) or ethyl pyruvate in lactated Ringers solution (0.05 g/kg loading dose over 10 min, thereafter 0.05 g· kg-1·h-1 for 12 h; EP treatment group, n=12).The parameters of respiratory mechanics, including lung dynamic compliance (Cdyn), lung total compliance (Ctot), inspiratory airway resistance (Rawi), peak inspiratory pressure (PIP), work of breathing (WOB), and arterial blood gases were monitored every 4 h after basic measurements (pre-LPS).The contents of TNF-α, IL-6 and IL-10 in serum were also detected by ELISA and compared between two groups.RESULTS:The changes of respiratory mechanics and arterial blood gases were in line with acute lung injury after septic shock induced by LPS.Oxygen index (OI), HCO-3and pH dropped 4 h after septic shock.On the contrary, PCO2 elevated significantly compared with that of septic shock before (P<0.05).Cdyn, Ctot decreased and Rawi, PIP, WOB increased significantly 8 h after septic shock (P<0.05).The changes in parameters of respiratory mechanics and arterial blood gases in control group were more distinguished than those in EP treatment group.There were significantly differences between two groups 8 h after septic shock (P<0.05).Although the significant improvement of respiratory mechanics was not observed, EP did prevent the parameters from worsening further more.Significantly differences between the two groups 12 h after septic shock (P<0.05) were found.Ethyl pyruvate also regulated the network of cytokines:increased the level of TNF-α, IL-6 and reduced the content of IL-10 in serum significantly compared with control group (P<0.05).CONCLUSION:Ethyl pyruvate has protective effects on acute lung injury in dogs with septic shock.     

Expression of urotensin II and its receptor in nephridial tissues of rats with acute renal damage

AIM: To observe the mRNA expression of urotensin II (UII) and its receptor (G protein-coupled receptor 14,GPR14) in nephridial tissues of rats with acute renal damage. METHODS: Male Wistar rats were divided into 2 groups: the rats in control group (n=10) were administered with normal saline by gavage; the rats in model group (n=30) were administered with Caulis Aristolochiae manshuriensis (CAM) by gavage for 25 d to induce acute renal damage. Every 5 rats in model group were sacrificed on the 3rd, 7th, 15th and 25th days during CAM treatment and all rats in the 2 groups were killed 10 d after withdraw of CAM. The kidneys were collected for pathological observation and the UII and GPR14 mRNA examination.RESULTS: The degeneration, necrosis and disintegration in tubules were observed as major pathological changes in the rat kidneys after 3 d of CAM administration. The pathological changes were aggravated following the duration of in CAM administration, and were remained and even worsen when CAM was withdrawn for 10 d. Compared with control group, the mRNA expression of UII was significantly elevated (P<0.05) at the time point of CAM administration for 15 d,even obviously increased (P<0.01) at the time point of CAM administration for 25 d, and remained at the highest levels to the end of the observation. The mRNA expression of GPR14 was significantly increased (P<0.05) at the time point of CAM administration for 7 d, became higher (P<0.01) on the 15th day, and gradually increased as the experimental time went on. CONCLUSION: The mRNA levels of UII and its receptor are significantly elevated in CAM-induced renal lesion in rats, suggesting that UII plays a pathological role in the development of acute renal damage.     

Effect of acupuncture on expression of EGF and bFGF in brain tissues of rats with traumatic brain injury

AIM: To observe the effect of acupuncture on the expression of epidermal growth factor (EGF) and basic fibrolblast growth factor (bFGF) in the brain tissues of rats with traumatic brain injury. METHODS: Thirty SD rats were randomized into sham-operated group, model group and acupuncture group. The model of traumatic brain injury was established by free drop impact. Acupuncture was performed to the rats in acupuncture group once every day and 7 days altogether. Brain histotomy was conducted after the treatment. Immunohistochemical method was adopted to test the protein expression of EGF and bFGF. RESULTS: Compared to sham-operated group, the expression of EGF in the brain tissues of model group decreased (P<0.01), and the expression of bFGF increased (P<0.01). Compared to model group, the expression of EGF and bFGF in acupuncture group increased obviously (P<0.01). CONCLUSION: Acupuncture significantly increases the expression of EGF and bFGF, and improves the repair of injured brain tissues. This might be one of the mechanisms by which acupuncture can treat traumatic brain injury and improve the nervous function.     

Effects of propofol on expression of AIF and cell apoptosis in brain tissues of the rats with LPS-induced brain injury

AIM: To investigate the effects of propofol on the expression of apoptosis-inducing factor (AIF) and cell apoptosis in brain tissues of rats with lipopolysaccharide(LPS)-induced brain injury. METHODS: Seventy-two male and female SD rats weighing 220~250 g were randomly divided into 3 groups (n=24 each). Cerebral edema was induced by injection of LPS at 1 mg/kg via left internal carotid artery in LPS group and LPS+propofol group. In control group, equal volume of normal saline was administered instead of LPS. The rats in LPS+propofol group received intraperitoneal injection of propofol at 100 mg/kg immediately after LPS administration. Six rats in each group were decapitated 6 h, 12 h, 24 h or 48 h after operation and the frontal lobe cortex were immediately removed for determination of the water content. The apoptotic neurons were detected by Annexin V-PI staining. The protein levels of AIF, NF-κB and caspase-3 were measured by immunohistochemistry. The protein expression of AIF was detected by Western blotting analysis. RESULTS: Compared with control group, the brain water content, the number of neuronal apoptosis and the protein expression levels of AIF, NF-κB and caspase-3 were significantly increased in LPS group and LPS+propofol group. Compared with LPS group, the results mentioned above were markedly reduced in LPS+propofol group. CONCLUSION: Propofol attenuates LPS-induced brain injury by decreasing AIF protein expression and inhibiting apoptosis.     

《果品品质研究》

AIM: To investigate the effects of diazoxide, an ATP-sensitive K⁺ channel opener on the μ-calpain activation, c-Fos and c-Jun expression in neonatal hypoxic-ischemic rat brain. METHODS: The animal model of hypoxic-ischemic brain injury (HIBI) was made in the 7-day-old SD rats. Diazoxide was injected into the left lateral ventricle prior or post hypoxic-ischemia (HI) insults. Western blot was applied to detect the integrated density (ID) of the nuclear c-Fos and c-Jun at 4h, and the cleavage of cytosolic μ-calpain at 24 h after HI insults. RESULTS: Low c-Fos and c-Jun expressions from cortical and hippocampal samples were observed in the two diazoxide groups, and significant differences in their expressions were found by comparison with the HI controls (P<0.05 respectively). Furthermore, the administration of diazoxide prior or post HI insults inhibited the cleavage of μ-calpain. CONCLUSION: Diazoxide down-regulated the expression of c-Fos and c-Jun, and inhibited the activation of μ-calpain may contribute to the neuroprotection from as well as therapeutical effects on HIBI.     

Protective effect of quercetin on L-02 cells by inhibiting DNA damage of INH-induced mitochondrial oxidative stress

AIM: To investigate the role of reactive oxygen species(ROS)-mediated mitochondrial oxidative injury in isonicotinyl hydrazide(INH)-induced DNA damage and the protective effect of quercetin on L-02 cells. METHODS: The injury model of hepatocyte L-02cells in vitro induced by INH was established. The cells were divided into control group, INH group, low-dose quercetin group and high-dose quercetin group. The DNA damage of L-02 cells was evaluated by the comet test. The mitochondrion was prepared, and the level of mitochondrial ROS and the value of mitochondrial membrane potential(ΔΨ_m) were detected by fluorescent probes DCFH-DA and rhodamine 123. The content of MDA was measured by TBA method. The activity of SOD was assessed with the xanthine oxidase method. The protein expression of Bcl-2 and Bax was determined by Western blotting, and the value of Bax/Bcl-2 was calculated. RESULTS: INH induced obvious DNA damage, increased the level of mitochondrial ROS, the content of MDA and the value of Bax/Bcl-2, and markedly reduced the value of ΔΨ_m and the activity of SOD in the L-02 cells. Quercetin attenuated DNA damage, reduced the level of mitochondrial ROS, elevated the value of ΔΨ_m, declined the content of MDA, increased the activity of SOD and decreased the value of Bax/Bcl-2 in the L-02 cells. CONCLUSION: INH induces DNA damage in L-02 cells by generation of mitochondrial oxidative stress. Quercetin has a protective effect on L-02 cells to attenuate the INH-induced DNA damage by inhibiting ROS-mediated mitochondrial oxidative damage.     

Protective effect of Auricularia auricular-judae polysaccharide on pulmonary tissues of rats with LPS-induced acute lung injury

AIM: To investigate the effects of Auricularia auricular-judae polysaccharide(AAP) on pulmonary tissues of rats with LPS-induced acute lung injury(ALI) and its mechanisms.METHODS: Adult Sprague-Dawley rats were randomly divided into control group, LPS group,low-dose AAP group, middle-dose AAP group, high-dose APP group, and dexamethasone group. The rats were injected with LPS(8 mg/kg, ip) to induce ALI. The rats in the AAP groups were treated with AAP for 7 d before the induction of ALI. The protein concentration in the bronchoalveolar lavage fluid(BALF) was measured. The lung edema degree was measured by detecting the wet/dry weight ratio. The myeloper-oxidase(MPO), total antioxidant capacity(T-AOC), total superoxide dismutase(T-SOD), nitric oxide synthase(NOS) and malondialdehyde(MDA) levels were determined. The pathological changes of the lung tissues were evaluated by HE staining.RESULTS: Treatment with AAP significantly improved LPS-induced lung pathological changes, attenuated the protein concentration in the BALF and wet/dry weight ratio, inhibited the activities of MPO and NOS, reduced MDA level and increased the activities of T-AOC and T-SOD.CONCLUSION: AAP protects against LPS-induced acute lung injury in rats.     

Protective effect of rAAV2-NTF2 on blood-retinal barrier damage in diabetic rats

AIM: To explore the effect of rAAV2-NTF2 on the blood-retinal barrier damage in early stage diabetic retinopathy. METHODS: Retinal vasculature was observed by Evans blue. NTF2 gene was cloned into adeno-associated virus vector pSNAV. The recombinant pSNAV-NTF2 was transfected into BHK cells. After purification, high-titer rAAV2-NTF2. rAAV2-NTF2 at dose of 4 μL (titer 1.0×1012) were injected into left eyes and rAAV2-EGFP at the same does and titer were injected into the right eyes of 36 rats. After 1 month, diabetes mellitus were induced by STZ. One month after onset of diabetes, EB at a dose of 45 mg/kg was intravenously injected into the rats. Two hours later, both eyes were enucleated immediately after perfusion of 1% PFA-citric acid buffer solution. The retinas were then dissected away and placed in formamide to extract the dye. The concentration of dye was measured by spectrophotometer. RESULTS: Evans blue was contained in normal retinal vessels without leakage, with a very low level of background fluorescence. The vessels staining of diabetic rats’ retina showed increasing fluorescence, indicating the retina-blood barrier damage. Dye concentration, representing the degree of the BRB injury, was higher in retina of 1 month diabetic rats than that in normal rats (4.67 times, P<0.01), indicating retina-blood barrier break-down. Diabetic rats with rAAV2-NTF2 intravitreal injection showed decreased BRB breakdown (P<0.05). CONCLUSION: High expression of NTF-2 decreases the BRB dysfunction in DM rats.     

Protective effect of ambroxol against the lung damage in chronically hypoxic rats

AIM: To investigate the effect of ambroxol on pulmonary and vascular injury in chronically hypoxic rats. METHODS: 36 male Wistar rats were randomly divided into 3 groups: normal control,chronically intermittent hypoxia(CIH) and ambroxol precaution group(AP).The CIH and AP groups were made into the chronically hypoxic models.The mean pulmonary artery pressure(PAPM) and the levels of plasma superoxide dismutase(SOD) and plasma nitric oxide(NO),lipid peroxide(LPO) were determined. The levels of the lung homogenates SOD, LPO, NO and the changes in pulmonary vascular structure were also examined. RESULTS: The levels of plasma and lung homogenates SOD,NO in CIH group were respectively significantly lower than that of normal control and AP group( P <0.01),but the levels of plasma and lung homogenates LPO were significantly higher( P< 0.01). PAPM in AP group is significantly lower than that of CIH group( P< 0.01);The damage of pulmonary artery smooth muscle cells and extra cell matrix of AP group is much slighter than that of CIH group. CONCLUSION: Ambroxol might be an effective protector in chronically hypoxic rats.