Objective To investigate the changes in the expression of Egr-1, C-jun and IL-1? mRNA and protein in the lung injured by mechanical ventilation. Methods Forty male SD rats weighing 250-320 g were randomly divided into 5 groups (n = 8 each): group A received no mechanical ventilation; group B-E received mechanical ventilaion for 30 (B), 60 (C), 90 (D) and 120 (E) minutes. The animals were anesthetized with intraperitoneal 3% pentobarbital 35 mg?kg-1 , tracheostomized and mechnically ventilated (VT =42 ml?kg-1 , RR = 40 bpm, I: E = 1:2, FiO2 = 21 % ) . Arterial blood samples were taken for blood gas analysis. The animals were killed at the end of mechanical ventilation in group B-E and after tracheostomy in group A. The lungs were removed for microscopic examination using HE staining. The expression of Egr-1, C-jun and IL-1? mRNA and protein was detected by RT-PCR and immuno-histochemical technique respectively. Results There was no significant difference in PaO2 and SaO2 among the 5 groups while PaCO2 was significantly decreased in group B and C but increased in group E as compared with group A. The expression of Egr-1, C-jun and IL-1? mRNA and protein was significantly increased by mechanical ventilation in a duration - dependent manner. Histological studies demonstrated that the damage to the lung was correlated with the duration of mechanical ventilation in terms of perivascular inflammatouy cell infiltration, exudates and hemorrhage in the alveoli and thickening of alveolar walls. Conclusion The results of our study show that mechanical ventilation activates and upregulates the expression of the early response genes in a duration - dependent manner. The upregulation of the expression of these genes might be involved in the underlying mechanism of lung damage induced by mechanical ventilation.

Objective To investigate the effects of penehyclidine (PHCD) pretreatment on nuclear factor kappa B ( NF-kB ) activity during lipopolysaccharide ( LPS )-induced acute lung injury ( ALl ) in neonate rats.Methods Thirty 7-day old Wistar rats of both sexes weighing 18-21 g were randomly divided into 3 groups ( n =10 each): group Ⅰ control (group C); group Ⅱ LPS; group Ⅲ PHCD. Group Ⅱ and Ⅲ received intraperitoneal ( group IP) LPS 3 mg/kg. In group Ⅲ PHCD 5 mg/kg was administered IP at 30 min before LPS respectively. The animals were killed at 4 h after LPS administration. The lungs were immediately removed. The W/D lung weight ratio was measured. The TNF-α, IL-1 βand IL-10 content in the lung were detected by ELISA and expression of NF-kB p65 was detected by immuno-histochemical staining.Results LPS significantly increased W/D lung weight ratio, TNF-α, IL-1 β, IL-10 content and NF-kB p65 expression in the lung as compared with control group. PHCD administered before LPS significantly attenuated the LPS-induced changes. Electron microscopy showed that PHCD before LPS significandy ameliorated the LPS-induced histological damages. Conclusion Pretreatment with PHCD can attenuate LPS-induced acute lung injury though inhibition of NF-kB activation and inflammatory response of lung tissue in neonate rats.

Objective To evaluate the expression of ?-defensin-2(BD-2) gene and protein with ventilator-associated pneumonia(VAP) in the old and grown rats.Methods Fifty-eight normal healthy Sprague-Dawley rats were divided into the old group(400～460 g,15～18 months,n=29) and grown group(280～320 g,4～6 months,n=29).Each rat received ventilation(VT=12 ml/kg) through tracheal tube for 24h and was challenged intra-tracheally with Pseudomonas aeruginosa(0.2 ml).The mRNA and protein levels of BD-2 were detected by RT-PCR and Western blot analysis respectively. Results Compared with the grown group,the rats had more severe interstitial pulmonary edema in the old group.There was no dominant difference in BD-2 mRNA and protein expression between the grown group and old group within 3 h,but BD-2 expressions in the grown group were significantly higher at 3 h,6 h,12 h,1 d,2 d and 3 d than those in the old group(P

Objective To evaluate the effects of polymorphism of angiotensin Ⅱtype Ⅰ receptor (AT1R) gene A1166C on arterial blood pressure during cardiopulmonary bypass (CPB).Methods Eighty-two patients (46 male, 36 female) aged 17-55 yr undergoing surgical correction of congenital heart disease or valve replacement under moderate hypothermic CPB were studied. Blood sample was taken from each patient and gene type was identified by polymerase chain reaction and restriction fragment length polymorphism (PCR-RLFP) method. The patients were divided into mutation group and normai group according to whether there was an A→C replacement in 1166 position of the AT1R gene code. MAP was continuously recorded at 1 min intervals during CPB. The plasma level of angiotensin Ⅱ was measured before and 40 min after CPB was started. The relationship between the AT1R polymorphism and the fluctuation in MAP was analyzed. Results There were 7 heterozygote patients with AC gene type (mutation group) and 75 homozygote patients with AA gene type ( normal group) . The average MAP in mutation group ( n = 7) was 64 ?5 mm Hg, significantly higher than that in normal group [ (58 ? 8) mm Hg] . The amount of phentolamine given was significantly larger in mutation group. The plasma level of angiotensin Ⅱ was significantly increased during CPB as compared with the baseline level before CPB. There was no significant difference in plasma angiotensin Ⅱ level between the two groups either before or during CPB. Conclusion AT1R A1166C polymorphism results in significant increase in MAP during CPB and may be partly responsible for hyperperfusion.

Objective To investigate the variation of myocardial glycometabolism and the release of cardiac creatine kinase and cardiac troponin I on isolated rat heart after stimulated with hyperinsulinism.Methods Thirty Sprague-Dawley rats were random divided into five groups,and their hearts were taken out to be mounted onto a Langendorff perfusion apprartus to perfuse with krebs-Henseleit buffer contained diversity concentration of insulin as 0,10,20,30,50 U/L.The coronary effluent was collected on time,and the concentration of glum was determined to evaluate the glycometabolism of the rat heart,meanwhile the release of cardiac creutine kinase(CK)and cardiac troponin I were detected to evaluate the state of myocardial damage.Results Compared with control group,the rat hearts of the hyperinsulinism group had a significantly depression of glucose uptake and oxidation,and the level of CK and cTn-I in the coronary effluent was increased.Conclusion After the isolated rat hearts were stimulated with hyperinsulinism,the glucose uptake of cadiocyte were suppressed,myocardial insulin resistance appeared,and the rat myocardial got damaged.

Objective To evaluate the role of spinal CX3C chemokine receptor 1 (CX3CR1) in inflammatory pain and the relationship with calmodulin (CaM)-calmodulin-dependent protein kinaseⅡ(CaMKⅡ) signaling pathways in mice.Methods Ninety-six pathogen-free healthy male C57BL6 mice,weighing 25-27 g,were divided into 3 groups using a random number table:control group (group C,n=30),inflammatory pain group (group IP,n=36) and CX3CR1 antagonist group (group CA,n=30).Inflammatory pain was induced by injecting complete Freund′s adjuvant (CFA) 50 μl into the plantar surface of right hind paws in IP and CA groups,while the equal volume of normal saline was given instead in group C.In group CA,CX3CR1 antagonist (diluted to 1 μg/5 μl in phosphate buffer solution) was intrathecally injected at 1 h before CFA injection.The thermal paw withdrawal latency (TWL) was measured at 30 min before CFA injection (T0) and 30 min,1 h,2 h and 4 h after CFA injection (T2-4).The animals were then sacrificed,and the spinal cord was removed for determination of the expression of phosphorylated CaMKⅡ (p-CaMKⅡ),phosphorylated cyclic adenosine monophosphate response element-binding protein (p-CREB) and c-fos (by Western blot) and expression of CaMKⅡ,CREB and c-fos mRNA (using real-time polymerase chain reaction).Immunofluorescence was used to determine that p-CAMKⅡ was expressed in microglia.Results Compared with group C,the TWL was significantly shortened at T2-4,and the expression of p-CaMKⅡ,p-CREB and c-fos protein and mRNA was up-regulated at T1-4 in IP and CA groups (P<0.05).Compared with group IP,the TWL was significantly prolonged at T2-4,and the expression of p-CaMKⅡ,p-CREB and c-fos protein and mRNA was down-regulated at T1-4 in group CA (P<0.05).p-CaMKⅡ was co-expressed with the microglial specific biomarker.Conclusion CX3CR1 is involved in the development and maintenance of inflammatory pain through activating CaM-CaMKⅡsignaling pathways in mice.

Objective To investigate the role of calcineurin(CaN)in inflammatory pain in rats.Methods Seventy-five male Harlan-Sprague-Dawley rats,weighting of 200-300 g were randomly divided into 3 groups (n=25): group control (group C),group CFA (complete Freunds adjuvant) (group F) and group CaN+CFA (group NF).100 μl CFA were injected on the right hind claw preparaing for inflammatory pain models in groups F and NF,100 μl saline were injected on the right hind claw in group C.CaN 10 U was intracerebroventricular injected 1 d before CFA injection in group NF.Paw withdrawal thermal latency (PWTL) were measured in 30 min prior to (T0),0.5 h (T1),1 h (T2),2 h (T3) and 4 h (T4) after injection.The expression of CaN and nuclear factor kappa B (NF-κB),IL-1β,TNF-α and IL-10 in spinal cord were measured at each time point.Results The PWTL was significantly shorter at T2-T4 in group F,at T3,T4 in group NF than that at T0and in group C (P<0.05);The PWTL at T2-T4 in group NF was significantly longer than that in group F (P<0.05).CaN protein expression in spinal cord at T1-T4 in group F,at T2-T4 in group NF was significantly lower than that of T0 and in the group C,NF-κB p65 protein expression was significantly higher than that of T0 and in the group C (P<0.05).CaN gene and IL-10 protein content at T2-T4 in groups F and NF were significantly lower than that of group C and at T0,NF-κB gene and IL-1β,TNF-α protein content was significantly higher than that of group C and at T0 (P<0.05).CaN protein and CaN gene expression,IL-10 protein content in spinal cord tissue at T1-T4in group NF was significantly higher than that of group F,NF-κB p65 protein and NF-κB gene expression and contents of IL-1β,TNF-α protein were significantly lower than that of group F (P<0.05).Conclusion CaN adjusts pro-inflammatory and anti-inflammatory cytokines by reducing NF-κB and inhibiting the process of inflammatory pain in rats.

Objective To study the effect of synthesized peptide S247 on the activation of p38MAPK of ventilator- induced lung injury.Methods Thirty healthy male SD rats were divided into group A,group B,group C,n 10.All rats were performed with mechanical ventilation,group A with tidal volume(V_T)8 ml/kg,breathing rate(p)80/min;group B with tidal volume(V_T)40 ml/kg,breathing rate(p)=80/min;group C with tidal volume(V_T)40 ml/kg,breathing rate(p)80/min.The rats in group C were intraperitoneally injected with synthesized peptide S247(100 mg/kg)once a day for a week.The time of ventilation in all groups was two hours.Rats were sacrificed after the experiment was finished. The lung lavage liquid and lung tissue were collected and stored with correct methods.The measured indexes included lung pathology change,total protein,WBC,MPO and MIP-2.The expression of p38 and p-p38 were measured by Western Blot in lung tissue.Results Compared with group A,total protein,WBC,MPO,MIP-2 and p-p38 significantly increased in group B;compared with group B,total protein,WBC,MPO,MIP-2 and p-p38 significandy decreased in group C. Conclusion Synthesized peptide S247 significantly inhibited the activation of p38 and relieved the degree of ventilator induced lung injury.

Objective To evaluate the role of GABAA receptors in uninjured dorsal root ganglion(L4DRG)in a rat model of neuropathic pain.Methods Thirty adult female SD rats weighing 200-250 g were randomly divided into 3 groups(n = 10 each): control group(group C),muscimol group(group M)and bicuculline group(group B).Neuropathic pain was produced by L5 spinal nerve ligation.Normal saline 50 μl,GABAA receptor agonist-muscimol 50 μl or GABAA receptor antagonist- bicucullin 50 μl was injected into the L4 DRG.The thermal pain threshold and mechanical pain threshold were measured and recorded from 1 day before operation to 10 days after operation.Results Compared with group C,the mechanical pain threshold was significantly increased(P ＜ 0.05),while no significant difference was found in thermal pain threshold in group M(P ＞ 0.05),and the thermal pain threshold and mechanical pain threshold were significantly decreased in group B(P ＜ 0.05).Conclusion Activation of GABAA receptors in uninjured DRG is involved in mechanical hyperalgesia in a rat model of neuropathic pain,but it dose not play a leading role.

Objective To investigate the change in GABA receptor-activated current in dorsal root ganglion (DRG) neurons in rats with neuropathic pain. Methods Twenty adult SD rats of both sexes weighing 100-150 g were randomly divided into 2 gorups: sham operation group (group S, n = 5) and neuropathic pain group (group NP, n= 15). Neuropathic pain was induced by ligation of right L5 spinal nerve. The animals were sacrificed at 5 days after operation. The L5 DRG( neurons in group NP and L3-5 DRG neurons in group S were immediately isolated. Whole-cellpatch- clamp technique was used. The extracellular solution contained GABA 100μmol/L.The frequency and amplitude of the GABA-activated current in DRG neurons and the changes in action potential (threshold potential, rheobase and overshoot) and resting potential before and after GABA administration were recorded. Results GABA 100μmol/L induced rapid inactivation of inward current in most neurons. Compared with the baseline before application of GABA, in group S GABA induced depolarization,increased resting potential and decreased amplitude and rheobase of action potential in large and medium DRG neurons, while in group NP GABA increased resting potential but induced no significant change in threshold potential and rheobase and overshoot of action potential. The frequency and amplitude of GABA-activated current and the degree of change in resting potential and rheobase and overshoot of action potential were significantly lower in group NP than in group S.Spontaneous discharge occurred in small DRG neurons in both groups. No GABA-activated current was observed in all DRG neurons with spontaneous discharge. Conclusions Neuropathic pain is induced by decreasing GABA-mediated inhibition signals in large and medium DRG neurons leading to increased excitability of neurons.