Effect of diltiazem on pulmonary arterial pressure and ceNOS mRNA expression in pulmonary arteries in chronic hypoxic hypercapnic rats

AIM: To investigate the effect of diltiazem on mean pulmonary arterial pressure (mPAP) and nitric oxide synthase (NOS) in arterioles in chronic hypoxic hypercapnic rats. METHODS: Twenty-four rats were randomly divided into three groups: control group (A), hypoxic hypercapnic group (B), hypoxic hypercapnia+ diltiazem group (C), constitutive endothelial NOS (ceNOS) were observed in arterioles of rats using the technique of immunohistochemistry, ceNOS mRNA were observed by the technique of in situ hybridization. RESULTS: (1) mPAP was significantly higher in rats of B group than that of A and C group(P<0.01). Differences of mCAP were not significant between A group and B groups (P>0.05), but mCAP was lower in rats of C group than that in B group. (2) Light microscopy showed WA/TA (vessel wall area/total area) was significantly lower in rats of C group than that of B group (P<0.01), electron microscopy showed that diltiazem inhibited the proliferation of smooth muscle cells and collageous fibers of pulmonary arterioles in chronic hypoxic hypercapnic rats. (3) Immunohistochemistry showed the average value of integral light density (LD) of ceNOS in pulmonary arterioles was significantly higher in rats of C group than that of B group (P<0.01), in situ hybridization showed LD of ceNOS mRNA in pulmonary arterioles was significantly higher in rats of C group than that of B group (P<0.01). CONCLUSION: Diltiazem inhibited pulmonary hypertension, the proliferation of smooth muscle cells and collagenous fibers of pulmonary arterioles in chronic hypoxic hypercapnic rats by incresing the expression of ceNOS in pulmonary arterioles.     

The regulation of nitric-oxide synthase/nitric-oxide system by endogenous carbon monoxide in rats with pulmonary hypertension

AIM:To study the role and the mechanism of heme oxygenas/endogenous carbon monoxide on nitric oxide synthase/nitric oxide system in rats with pulmonary hypertension induced by hypoxic hypercapnia.METHODS:Sprague-Dawley rats were randomly divided into three groups: control group (A group), hypoxic hypercapnic group (B group), hypoxic hypercapnia+hemin group (C group). Blood CO concentration (COHb%), NO concentration, HO-1 activity, iNOS, cNOS in blood serum and lung homogenate were measured, respectively. RESULTS:① mPAP and RV/(LV+S) of B group were significantly higher than those of A and C group(P＜0.01).② Blood CO concentration, activity of HO-1in blood serum and lung homogenate in rats of B group were significantly higher than those of A group, but were significantly lower than those of C group (P＜0.01). ③ NO concentration in blood serum and lung homogenate in rats of B group were significantly lower than those of A group, those of C group were significantly higher than those of B group (P＜0.01).④The activity of iNOS in blood serum and lung homogenate in rats of B group were significantly higher than those of A group, but were significantly lower than those of C group (P＜0.01). Activity of cNOS in blood serum and lung homogenate of B group were significantly lower than those of A group (P＜0.01), and there was no significant difference between cNOS in B and C group.CONCLUSION:Endogenous carbon monoxide upregulated iNOS/NO system in rats with chronic pulmonary hypertension induced by hypoxic hypercapnia.     

Effect of safflower injection on expression of COX-2 mRNA and protein in chronic hypoxic hypercapnic rat pulmonary arterioles

AIM:To study the effect of safflower injection on expression of COX-2 mRNA in chronic hypoxic hypercapnic rat pulmonary arterioles.METHODS: Sprague-Dawley rats were randomly divided into normal control group, hypoxic hypercapnic group (B), hypoxic hypercapnia+ safflower injection group (C). The concentration of TXB2 and 6-Keto-PGF1α in plasma and in lung were detected by the technique of radioimmunoassay. COX-2 mRNA was observed in arterioles from rats by the technique of in situ hybridization. RESULTS: ① Mean pulmonary arterial pressure(mPAP), weight ratio of right ventricle (RV) to left ventricle plus septum (LV+S) were much higher in B group than those in control group. No significant difference of mean carotid arterial pressure(mCAP) was observed in three groups. ② The concentration of TXB2 and the ratio of TXB2/6-keto-PGF1α were significantly higher in B group than those in control group. ③ Light microscopy showed that vessel wall area/total area, the density of medial smooth muscle cells and the thickness of medial smooth cell layer were significantly higher in B group than those in control group. Electron microscopy showed proliferation of medial smooth muscle cells and collagenous fibers in pulmonary arterioles in B group. Safflower injection reversed the changes mentioned above. ④ Expression of COX-2 mRNA in pulmonary arterioles was much higher in C group than those in B group. Differences of COX-1 mRNA in pulmonary arterioles were not significant between these two groups.CONCLUSION:Safflower injection increases the expression of COX-2 mRNA in chronic hypoxic hypercapnic rat pulmonary arterioles, indicating an important mechanism that safflower injection inhibits the formation of hypoxic hypercapnia pulmonary hypertension and pulmonary vessel remodeling.     

Effect of ligustrazine on pulmonary arterial pressure and pulmonary arterial wall collagen of chronic hypoxic hypercapnic rats

AIM:To study the effect of ligustrazine on pulmonary hypertensive rats induced by hypoxic hypercapnia. METHODS:Thirty rats were randomly divided into three groups:control group(A),hypoxic hypercapnic group(B), hypoxic hypercapnia+ligustrazine(lig.) group(C). RESULTS: (1) Mean pulmonary arterial pressure(mPAP)of group B was significantly higher than that of group A and mPAP of group C was significantly lower than that of group B(P＜0.01),differences of mean carotid pressure(mCAP) were not significant among three groups (P＞0.05); (2)Electron microscopy and immunohistochemistry showed ligustrazine could inhibit the diposition of collagenous fiber(collagen typeⅠ)in pulmonary arterioles induced by hypoxic hypercapnia; (3) Plasma endothelin level of group C was significantly lower than that of group B (P＜0.01), serum (NO ₂^-/NO₃^-) of group C was significantly higher than that of group B (P＜0.01). CONCLUSION:Ligustrazine can inhibit pulmonary hypertension and the diposition of collagen type Ⅰ in pulmonary arterial wall induced by hypoxic hypercapnia.     

Expression and distribution of osteopontin in the development of pulmonary hypertension induced by hypoxia-hypercapnia

AIM: To study the expression and distribution of osteopontin (OPN) in lungs and pulmonary arteries in pulmonary hypertensive rats induced by hypoxia-hypercapnia, and to explore the role of OPN in pathogenesis of pulmonary hypertension. METHODS: Forty-eight male Sprague-Dawley rats (Weight 180 g-220 g) were randomly divided into four groups: normal control group (NC), hypoxic hypercapnia 1-week，2-week and 4-week group (1HH, 2HH and 4HH). The expressions of OPN mRNA and protein in lungs and pulmonary arteries were detected by RT-PCR and immunohistochemistry. ELISA was used to detect the concentration of OPN in lung homogenates. The content of OPN in pulmonary arteries was detected by Western blotting. RESULTS: ① The mean pulmonary artery pressure (mPAP) and weight ratio of right ventricle to left ventricle and septum ［RV/(LV+S)］ in all hypoxic hypercapniac groups were higher than those in normal control group (P<0.01), respectively. Differences of mean carotid artery pressure (mCAP) among these four groups were not significant (P>0.05). ② The expression of OPN mRNA was significantly increased in pulmonary arteries and lung tissues in hypoxic hypercapnic groups compared with normal control group (P<0.01). ③ The result of immunohistochemistry showed that OPN was only detected in bronchus and alveolar epithelium, but not detected in pulmonary arterioles of normal control group. In contrast，OPN expression was evident in pulmonary arterioles of 1HH rats，especially in media. Moreover, the expression of OPN was markedly increased in group 2HH and 4HH. ④ OPN levels in lung homogenates in 1HH, 2HH and 4HH were increased by 69%, 128% and 187% (P<0.01), respectively, compared with control rats. ⑤ Western blotting analysis showed that the contents of OPN were significantly higher in all hypoxic hypercapnic groups than those in NC group (P<0.01).CONCLUSION: The expressions of OPN in pulmonary arteioles and lung are increased in rats with pulmonary hypertension. OPN might play an important role in the pathogenesis of pulmonary hypertension induced by chronic hypoxia and hypercapnia.     

Effect of nitric oxide on urotensin-Ⅱ expression in pulmonary arterioles of rats chronically exposed to hypoxia-hypercapnia

AIM: To investigate the roles of nitric oxide/L-arginine (NO/L-Arg) pathway and urotensin-Ⅱ (UⅡ) in the development of pulmonary hypertension induced by chronic hypoxia-hypercapnia in rats.METHODS: Forty male Sprague-Dawley rats were randomly divided into four groups (n=10): normal control group (A), hypoxia-hypercapnia+saline group (B), hypoxia-hypercapnia+L-Arg liposome group (C) and hypoxia-hypercapnia+N-nitro-L-arginine methyl ester (L-NAME) group (D).Contents of UⅡ, UⅡ mRNA and receptor of UⅡ (UT) mRNA in pulmonary arterioles were measured with immunohistochemistry analysis and in situ hybridization, respectively.Change of small pulmonary vascular microstructure was also investigated.RESULTS: (1) The mean pulmonary artery pressure (mPAP) and the weight ratio of right ventricle to left ventricle plus septum ［RV/(LV+S)］ in B and D groups were all higher than those in A group (respectively, P<0.05), with C group significantly lower than those in B group (respectively, P<0.01).(2) Light microscopy showed that the ratio of vessel wall area to total area (WA/TA) and the media thickness of pulmonary arterioles (PAMT) in B group were higher than those in A group (P<0.05), with C group significantly lower than those in B group.(3) The contents of UⅡ, UⅡ mRNA and UT mRNA in pulmonary arterioles in B and D groups were all higher than those in A group (respectively, P<0.01), while the expression of UⅡ and UⅡ mRNA in C group were lower than those in B group (P<0.01).CONCLUSION: The pathological process of pulmonary hypertension induced by chronic hypoxia-hypercapnia might be related to upregulation of UⅡ located in pulmonary arterioles, which might be partially inhibited by exogenous NO in rats.     

Effect of ligustrazine on hydrogen sulfide system in lung tissue of rats with pulmonary hypertension induced by hypoxic hypercapnia

AIM: To investigate the effect of ligustrazine on hydrogen sulfide (H2S) system in pulmonary hypertension induced by hypoxic hypercapnia in rats. METHODS: Thirty Sprague-Dawley rats were randomly divided into 3 groups: control group (C), hypoxic hypercapnia group (HH), and hypoxic hypercapnia+ligustrazine group (HH+L). The change of hemodynamics was measured. The ratio of vessel wall area and total area of arteriae pulmonalis were observed under light microscope. The apoptosis of arteriae pulmonalis was tested with TdT-mediated dUTP nick end labeling (TUNEL), and the apoptosis index was calculated. Plasma level of hydrogen sulfide and activity of hydrogen sulfide generating enzymes in homogenates of rat lung tissue were evaluated by sensitive modified sulfide electrode method. Cystathionine-γ-lyase (CSE) mRNA in lung tissues was determined by RT-PCR. RESULTS: The level of mean pulmonary arterial pressure, the ratio of vessel wall area/total area and the right ventricle/left ventricle+septum were significantly higher in HH group than those in C group, and the value was obviously lower in HH+LTZ group than that in HH group (all P<0.01). The mean carotid arterial pressure of 3 groups had no significant difference (P>0.05). The apoptotic index of arteriae pulmonalis in HH group and HH+LTZ group was significantly lower than that in C group, and that in HH+LTZ group was significantly higher than that in HH group (P<0.05 or P<0.01). Plasma level of H2S, the activity of H2S generating enzymes in homogenates of rat lung tissue, cystathionine-γ-lyase (CSE) mRNA in lung tissues in HH group were significantly lower than those in C group (all P<0.01), and those in HH+LTZ group were significantly lower than those in HH group (all P<0.01). CONCLUSION: Ligustrazine up-regulates the expression of cystanthionine-γ-splitting enzyme (CSE), enhances the activity of CSE and increases the level of H2S to prevent pulmonary hypertension induced by hypoxic hypercapnia.     

Effect of hydroxylamine on pulmonary arterial hypertension induced by chronic hypoxic hypercapnia in rats

AIM: To explore the effects of hydroxylamine on the pulmonary arterial pressure in chronic hypoxic hypercapnic rats. METHODS: Twenty-four male Sprague-Dawley rats were randomly divided into 3 groups (8 rats in each group): the normal control group (NC), hypoxic hypercapnia+normal saline group (NS), hypoxic hypercapnia+hydroxylamine group (HA). The animals in NS and HA groups were kept in the O₂ (9%-11%) and CO₂ (5%-6%) cabin, 8 h a day and 6 days a week for 4 weeks. Before entering the cabin, the rats in HA group were administered with 1 mL hydroxylamine (12.5 mg/kg) by intraperitoneal injection, while the rats in NS group were given intraperitoneal injection of 1 mL saline solution. The mean pulmonary arterial pressure (mPAP) was measured by external jugular vein cannulation. The heart was removed, and the right ventricle (RV) and the left ventricle plus the septum (LV+S) were dissected. The ratio of the wet weight of the RV to that of the LV+S was calculated. The changes of the pulmonary vascular construction were observed under optical microscope. The concentration of H₂S in the plasma was measured with a spectrometer. The expression of cystathionine-γ-lyase (CSE) in the pulmonary arterioles and bronchi was measured by immunohistochemistry and RT-PCR. RESULTS: The values of mPAP, RV/(LV+S),vessel wall area/total area (WA/TA) and media thickness of pulmonary arterioles (PAMT) in NS group and HA group were significantly higher than those in NC group (P<0.05). The level of H₂S in the plasma, the content of CSE protein and the expression of CSE mRNA in NC group were significantly lower than those in NS group (P<0.05). The values of mPAP, RV/(LV+S), WA/TA and PAMT in HA group were significantly lower than those in NS group (P<0.05). The level of H₂S in the plasma, the content of CSE protein and the expression of CSE mRNA in HA group were significantly higher than those in NS group (P<0.05). CONCLUSION: Hydroxylamine may decrease the pulmonary arterial hypertension induced by chronic hypoxic hypercapnia in rats by increasing the level of H₂S in the plasma, the content of CSE protein and the mRNA expression of CSE, thus improving the pulmonary vascular structural remodeling.     

Relationship between thromboxane synthase gene and prostacyclin synthase gene expression and pulmonary hypertension induced by hypoxic hypercapnia

AIM: To study the effect of chronic hypoxic hypercapnia on gene expression of thromboxane synthase and prostacyclin synthase in pulmonary arterioles. METHODS: Sprague-Dawley rats were randomly divided into two groups: control group and hypoxic hypercapnic group. TXS mRNA and PGI₂-SmRNA were observed in pulmonary arterioles by in situ hybridization. RESULTS: mPAP, weight ratio of right ventricle (RV) to left ventricle plus septum(LV+S), contents of TXB₂ and 6-keto-PGF1_α in plasma and lung and TXS mRNAin pulmonary arterioles were much higher in rats of hypoxic hypercapnic group than those of control group. Differences of PGI₂-SmRNA in pulmonary arterioles were not significant in two groups. Light microscopy showed hypertrophy of vessel smooth muscle cells and vessel cavity straitness were found in hypoxic hypercapnic group. CONCLUSION: Changes of gene expressions of thromboxane synthase and prostacyclin synthase and imbalance of TXA₂/PGI₂ may play an important role in hypoxic hypercapnic pulmonary hypertension.     

Effect of puerarin on pulmonary arterioles wall collagen metabolism of chronic hypoxia hypercapnia rats

AIM:To investigate the effect of puerarin on pulmonary vessel collagen metabolism in pulmonary hypertension rats induced by chronic hypoxia and hypercapnia.METHODS:Collagen Ⅰ, Ⅲ and their mRNA were observed in pulmonary arterioles by the technique of immunohistochemistry and in situ hybridization.RESULTS:① Light microscopy showed media thickness of pulmonary arterioles was much higher in HH(hypoxic-hypercapnia) group than that of NC(normal control) group, and, vessel cavity turned more straiter in HH group than that of NC group.However, the damage of pulmonary arterioles in HP(hypoxic-pueratin) group was much slighter than that of HH group. ② The levels of plasma ET-1 and lung homogenates Hyr were much higher in HH group than those of NC group(P＜0.01), and lower in HP group than HH groups(P＜0.01).Plasma NO content in group HH was lower than that of group NC(P＜0.01), it was higher in group HP than that of group HH(P＜0.01).③Expression of collagen Ⅰ and collagen Ⅰ mRNA in pulmonary arterioles were significantly higher in HH groups than those of NC group (P＜0.01), and they were lower in HP group than those of HH group (P＜0.01).Expression of collagen Ⅲ and collagen Ⅲ mRNA showed no difference among three groups(P＞0.05).CONCLUSION:Puerarin inhibited the deposition of collagen and improved pulmonary vessel remodeling.     

Effect of hypercapnia on lysyl oxidase-dependent collagen cross-linking and hypoxia-induced pulmonary hypertension in rat

AIM: To investigate the effect of hypercapnia on hypoxia-induced pulmonary hypertension and the changes of lysyl oxidase (LOX) and extracellular matrix collagen cross-links in the rat. METHODS: Sprague-Dawley rats were randomly divided into 4 groups:normoxia group, hypoxia group, hypercapnia group and hypoxia+hypercapnia group. LOX activity was detected by fluorescence spectrophotometry. LOX protein expression was detected by immunohistochemistry and Western blot. The mRNA expression of LOX in the pulmonary artery was detected by real-time PCR. RESULTS: The levels of mean pulmonary artery pressure (mPAP), RV/(LV+S) and WA/TA in hypoxia group were significantly higher than those in normoxia group (P<0.01). Moreover, the levels of mPAP and RV/(LV+S) in hypoxia+hypercapnia group were significantly lower than those in hypoxia group (P<0.01). However, no significant difference of mPAP and RV/(LV+S) between hypercapnia group and normoxia group was observed. In hypoxia group, the collagen cross-links in the lung tissue was significantly higher than that in normoxia group and hypercapnia group (P<0.01). Importantly, collagen cross-links in the lung tissue of hypoxia+hypercapnia group was significantly lower than that in hypoxia group (P<0.01). There was no significant difference in collagen cross-links between hypercapnia group and normoxia group. The expression of LOX at mRNA and protein levels and its activity in the pulmonary arteries of hypoxia group were significantly increased as compared with normoxia group (P<0.01). Furthermore, the expression of LOX at mRNA and protein levels and its activity in the pulmonary arteries in hypoxia+hypercapnia group were lower than those in hypoxia group (P<0.01). CONCLUSION: Hypoxia not only up-regulates LOX but also promotes collagen cross-linking in the rat lung, which contributes to the development of pulmonary hypertension. Hypercapnia inhibits hypoxia-induced LOX expression and collagen cross-linking, therefore impairing the progress in hypoxia-induced pulmonary hypertension.     

Inhibitory effect of notoginsenoside monomer R1 on activation of p38 MAPK signaling pathway induced by hypoxic hypercapnia in PASMCs

AIM: To explore the mechanism of notoginsenoside monomer R₁ (R₁) against hypoxic hypercapnia-induced pulmonary vasoconstriction (HHPV) by investigating the effect of R₁ on p38 mitogen-activated protein kinase (p38MAPK) signaling pathway in pulmonary arterial smooth muscle cells (PASMCs) under the condition of hypoxia and hypercapnia. METHODS: Primary cultured PASMCs, which were isolated from Sprague-Dawley rats, were incubated in logarithmic growth phase from the 2nd to 5th generation with different concentrations (8, 40 and 100 mg/L) of R₁ under the condition of 6% CO₂ plus 1% O₂ for 24 h. The expression of p38 at mRNA and protein levels was detected by RT-PCR and Western blotting,respectively. RESULTS: The results of Western blotting and RT-PCR analysis indicated that the protein and mRNA expression levels of p-p38 MAPK were significantly higher in hypoxic hypercapnia group with DMSO control than those in normoxia control group (P<0.01). In R₁ treatment groups, the levels of p-p38 MAPK protein and p38 MAPK mRNA were markedly decreased (P<0.01) in a dose-dependent manner. CONCLUSION: p38 MAPK signaling pathway may mediate hypoxic hypercapnia pulmonary vasoconstriction in rats. Notoginsenoside monomer R₁ attenuates HHPV, which may be related to blockage of p38 MAPK signal pathway.     

Expression of MMP-2 mRNA and MMP-9 mRNA in pulmonary arterioles ofrats with pulmonary hypertension induced by chronic hypoxia hypercapnia

AIM:To investigate the expression of matrix metalloproteinases(MMPs) in pulmonary arterioles of rats with chronic hypoxia and hypercapnia-induced pulmonary hypertension.METHODS:MMP-2, MMP-9 and MMP-2 mRNA, MMP-9 mRNA were observed in pulmonary arterioles by the techniques of immunohistochemistry and in situ hybridization.RESULTS:①The mean pulmonary artery pressure (mPAP) and weight ratio of right ventricle to left ventricle and septum (RV/LV+S) of hypoxia-hypercapnia groups were higher than those of normal control group (P＜0.01). ②Light microscopy showed that vessel wall and media of pulmonary arterioles were thicker in rats of hypoxia-hypercapnia groups than normal control group. There were vessel smooth muscle cell hypertrophy, vessel cavity straitness in hypoxia-hypercapnia group, but no same performance was found in normal control group. ③The expression of MMP-2, MMP-9 and MMP-2 mRNA, MMP-9 mRNA in pulmonary arterioles were significantly higher in rats of hypoxia-hypercapnia groups than control group (P＜0.01).CONCLUSION:Expression of matrix metalloproteinases in pulmonary arterioles is enhanced by hypoxia hypercapnia. This may be involved in pulmonary vascular remodeling in rats with pulmonary hypertension.     

Roles of ERK pathway and Panax notoginoside treatment in hypoxic hypercapnia pulmonary hypertension in rats

AIM: To investigate the roles of Panax notoginoside (PNS) and ERK1/2 signaling pathway in the pathological process of chronic hypoxic hypercapnia pulmonary hypertension in rats.METHODS: The animal model of chronic hypoxic hypercapnia pulmonary hypertension was set up in 72 male Sprague-Dawley rats and the animals were randomly divided into 6 groups: normal (N) group, hypoxic hypercapnia for 3-day (H_3d) group, hypoxic hypercapnia for 1-week (H_1w) group, hypoxic hypercapnia for 2-week (H_2w) group, hypoxic hypercapnia for 4-week (H_4w) group and PNS treatment (H_p) group.The rats in H_p group were injected with PNS (50 mg·kg^-1·d^-1, ip) before placing the animals into the hypoxic hypercapnia chamber.The rats in other groups were injected with normal saline (2 mL/kg, ip).The morphological changes of the pulmonary artery were observed under microscope with HE staining.Western blotting was used to detect the protein expression of p-ERK.The protein levels of p-ERK in the lung tissues and pulmonary blood vessels were determined by immunohistochemistry.RESULTS: The ratios of WA/TA in H_1w, H_2w, H_4w and H_p groups were higher than that in N group (P<0.05).The ratio of WA/TA in H_p group was obviously lower than that in H_4w group (P<0.05).The protein expression of p-ERK was barely positive in N group, but was up-regulated in the pulmonary tissues in all hypoxic rats.Compared with N group, the protein level of p-ERK was markedly up-regulated in H_3d group, reached its peak in H_2w group, and tended to decline in H_4w group (P<0.05).In pulmonary arterial tunica intima and tunica media, p-ERK protein was dramatically expressed in all hypoxic rats compared with the control animals (P<0.05).In the lung tissues, the protein level of p-ERK in H_p group was lower than that in H_4w group (P<0.05).In pulmonary arterial tunica intima and tunica media, the protein level of p-ERK in H_p group was lower by 84.86% than that in H_4w group (P<0.05).CONCLUSION: ERK1/2 as a signal transducer may play an important role in the development of hypoxia and hypercapnia induced pulmonary hypertension.PNS inhibits the expression of ERK1/2, thus attenuating the development of pulmonary hypertension and improving pulmonary vascular remodeling.     

Effect of Panax notoginoside on pulmonary arterial pressure and expression of p38 MAPK in lung tissues of hypoxic rats

AIM: To observe the effect of Panax notoginoside (PNS) on the pulmonary artery pressure and the p38 mitogen-activated protein kinase(p38 MAPK) in lung tissues of rats treated with hypoxia. METHODS: Thirty adult male SD rats were randomly divided into 3 groups. The rats in normal control group were exposed to normal conditions, the rats in hypoxia group were exposed to isobaric hypoxia, and the rats in hypoxia+PNS group were treated with PNS under the condition of hypoxia. After 4 weeks of treatment, the mean pulmonary arterial pressure (mPAP) and the mean carotid arterial pressure (mCAP) were measured by cardiac catheterization. The heart was isolated, and the right ventricle (RV), left ventricle plus ventricular septum (LV+S) were weighed to calculate the ratio of RV/(LV+S).The quantity of phospho-p38 MAPK(p-p38 MAPK) in rat pulmonary arterioles was determined by the method of immunohistochemistry and the mRNA content of p38 MAPK was tested by RT-PCR. RESULTS: The mPAP and RV/(LV+S) in hypoxia group were higher than those in normal control group. The expression of p-p38 MAPK in rat pulmonary arterioles and p38 MAPK mRNA in the lung tissues were higher than those in normal control group (P<0.05). The mPAP, RV/(LV+S), the expression of p-p38 MAPK in rat pulmonary arterioles and p38 MAPK mRNA in the lung tissues in hypoxia+PNS group were significantly lower than those in hypoxia group (P<0.05).CONCLUSION: PNS possesses the preventive and therapeutic effect on hypoxic pulmonary hypertension by decreasing p-p38 MAPK and down-regulation of p38 MAPK mRNA in the lungs.     

Effect of puerarin on monocrotaline-induced pulmonary hypertension and expression of chemokine CX3CL1/fractalkine

AIM: To observe the change of CX₃CL1/fractalkine (FKN) in the rats with monocrotaline-induced pulmonary hypertension, and to study the intervention of puerarin. METHODS: The pulmonary hypertension model was established in vivo by intraperitoneal injection of monocrotaline. Thirty male Sprague-Dawley rats (270-310 g) were randomly divided into 3 groups: control group (C), monocrotaline model group (M)and puerarin treatment group (M+P). The mean pulmonary arterial pressure (mPAP), mean right ventricular pressure (mRVP), mean carotid arterial pressure (mCAP) and the weight ratio of right ventricle (RV) to left ventricle plus septum (LV+S) were also detected. The structural changes of pulmonary arterioles were observed under optical microscope. Remodeling of lung blood vessels was determined by measuring the ratio of vessel wall area to total area (WA/TA) and the medium thickness of pulmonary artery (PAMT). The concentration of soluble fractalkine(sFKN) in plasma was measured by ELISA. The expression of FKN in the pulmonary artery wall was measured by immunohistochemistry. The mRNA level of FKN in the lung tissues was detected by RT-PCR.RESULTS: mPAP, mRVP, RV/(LV+S), WA/TA and PAMT in M group were higher than those in C group (P<0.01). RV/(LV+S), WA/TA and PAMT in M+P group were significantly lower than those in M group (P<0.01). No significant difference of mCAP among the 3 groups was observed. The levels of sFKN, FKN mRNA and FKN protein in M group were higher than those in C group (P<0.01), and the above data in M+P group were lower than those in M group(P<0.05). The serum level of sFKN had a positive correlation with PAMT and RV/(LV+S) (r＝0.719, r=0.685,respectively, P<0.01).CONCLUSION: Puerarin down-regulates the expression of FKN and suppresses the development of pulmonary hypertension and pulmonary vessel remodeling.     

Role of heme oxygenase-1/carbon monoxide system in pulmonary ischemia-reperfusion injury

AIM: To investigate the effect of heme oxygenase-1 (HO-1)/carbon monoxide (CO) system on pulmonary ischemia-reperfusion injury (PIRI) in rabbits. METHODS: Single lung ischemia and reperfusion animal model was used in vivo. The rabbits were randomly divided into three groups (n=10 in each), control group (C), PIR group (I-R), PIR+ hemin group (H) and PIR+zinc protoporphyrin IX (ZnPP) group (Z). Changes of several parameters which included plasma carboxyhemoglobin (COHb) at different time points, wet to dry ratio of lung tissue weight (W/D), the injured alveoli rate (IAR) and the HO-1 enzymatic activity were measured at 180 min after reperfusion in lung tissue. The tissue slides were also stained by immunohistochemistry (IHC) and in situ hybridization (ISH) for HO-1 to detect the expression of HO-1 in lung and to analyze the optical density. The lung tissue was prepared for electron microscopic observation at 180 min after reperfusion. RESULTS: The plasma content of COHb in I-R, H, and Z group increased in a time-dependent manner after I-R. But the increment of H group was higher than that of I-R group, while that of Z group was lower. The HO-1 activity in lung tissue was highest in H group, followed by IR group, Z group, and C group (P<0.05 and P<0.01). Except C group, HO-1 was upregulated in all other groups in the pulmonary endothelial cells, part of pulmonary vascular smooth muscle cells, extima of vessels and epithelial cells of airway. H group had the highest average optical density value, then the IR group, Z group and C group (P<0.05 and P<0.01). The value of W/D and IAR was highest in Z group, the second was in IR group, then the H group and C group (P<0.05 and P<0.01). The abnormal changes of the lung tissue in morphology in I-R group, Hemin treatment mitigated the injury of I-R in H group and ZnPP exacerbated the impairment of ultrastructure in Z group were also observed. CONCLUSION: HO-1/CO system possesses notable protective effects on lung during pulmonary ischemia-reperfusion injury in rabbits.     

“中国园艺学会第七届青年学术讨论会”

中国园艺学会第九届第8次常务理事扩大会决定，“中国园艺学会第七届青年学术讨论会”由山东农业大学园艺科学与工程学院和山东省园艺学会承办，将于2006年7月或8月在山东泰安举行。