This paper aims to evaluate the pharmacodynamic effect and mechanism of Zhifuxin in the prevention and treatment of vascular dementia(VD), providing a theoretical basis for later development. Bilateral common carotid artery ligation in male Wistar rats was conducted to replicate the long-term hypoperfused VD model, and the drug was given to groups after one month. The rats were fed daily with nimodipine of 20 mg·kg~(-1), Zhifuxin of 50, 100, and 200 mg·kg~(-1), or the same volume of solvent for four weeks. 24 hours after the last dose, Morris water maze experiments were performed to detect the learning and memory abilities of rats. Hematoxylin-eosin(HE) staining was used to observe the pathological changes in the brain tissue of rats; the immunohistochemical method was used to detect the expression of muscarinic acetylcholine receptors M1 and M4 in rats and determine the content of acetyl choline(Ach), acetylcholin esterase(AchE), malondialdehyde(MDA), choline acetyl transferase(ChAT), and dimethyl arginine hydrolase 1(DDAH1) in the cerebral cortex of rats. Western blot was employed to detect protein expression of endothelial nitric oxide synthase(eNOS), caveolin-1, monoamine oxidase A(MAO-A), and monoamine oxidase B(MAO-B). RT-qPCR was utilized to detect mRNA expression of eNOS, caveolin-1, MAO-A, and MAO-B. The results showed that compared with the model group, the different doses of Zhifuxin were able to shorten the latency of VD rats in the water maze positioning navigation test, increase the number of crossing platforms in the space exploration test, and alleviate cone cell contracture in the hippocampus of VD rats. The expression of biochemical indicators related to the cholinergic system in the cerebral cortex: M1 and M4 receptors increased, as well as ChAT activity, and AchE activity significantly decreased. The protein and mRNA expression of indicators related to the eNOS/NO pathway: DDAH1 content, eNOS, and caveolin-1 increased, and that of indicators related to monoamine oxidase(MAO): MAO-A and MAO-B significantly decreased. The results show that Zhifuxin can improve cognition ability in long-term hypoperfused VD rats, and its mechanism of action may be related to its ability to modulate the cholinergic system and the eNOS/NO pathway and inhibit MAO expression.
Animals ; Dementia, Vascular/metabolism* ; Male ; Rats, Wistar ; Rats ; Drugs, Chinese Herbal/administration & dosage* ; Maze Learning/drug effects* ; Nitric Oxide Synthase Type III/genetics* ; Acetylcholinesterase/metabolism* ; Humans ; Choline O-Acetyltransferase/genetics* ; Disease Models, Animal

Objective To explore the effects of Shuanglu Tongnao Formula on neuroinflammation in ischemic stroke (IS) rats via the P2X purinoceptor 7 receptor (P2X7R)/NLR family pyrin domain-containing 3 (NLRP3) pathway. Methods The rats were divided into five groups: the IS group, control group, Shuanglu Tongnao Formula group, P2X7R inhibitor brilliant blue G (BBG) group, and Shuanglu Tongnao Formula combined with P2X7R activator adenosine triphosphate (ATP) group, with 18 rats in each group. Except for the control group, rats in all other groups were used to construct an IS model using the suture method. After successful modeling, the drug was given once a day for 2 weeks. Neurological function scores and cerebral infarction volume ratios were measured in rats. Pathological examination of the ischemic penumbra brain tissue was performed. Immunofluorescence staining was used to quantify the proportions of microglia co-expressing both inducible nitric oxide synthase (iNOS) and ionized calcium-binding adapter molecule 1 (Iba1), as well as arginase 1 (Arg1) and Iba1, in the ischemic penumbra brain tissue. ELISA was used to detect tumor necrosis factor-alpha (TNF-α), transforming growth factor-beta (TGF-β), interleukin 6 (IL-6) and IL-10 in the ischemic penumbra brain tissue. Western blotting was used to measure P2X7R, NLRP3, and IL-1β proteins in the ischemic penumbra brain tissue. Results Compared with the control group, the IS group showed disordered neuronal arrangement, nuclear condensation, and obvious infiltration of inflammatory cells in the ischemic penumbra; significantly elevated neurological function scores, cerebral infarction volume ratios, proportions of microglia co-expressing iNOS and Iba1, and levels of TNF-α, IL-6, and P2X7R, NLRP3, IL-1β proteins; along with reduced proportions of microglia co-expressing Arg1 and Iba1 and levels of TGF-β and IL-10. Compared with the IS group, the Zhuang medicine Shuanglu Tongnao Formula and BBG groups demonstrated alleviated brain tissue damage; reduced neurological function scores, cerebral infarction volume ratios, proportions of microglia co-expressing iNOS and Iba1, and levels of TNF-α, IL-6, and P2X7R, NLRP3, IL-1β proteins; along with increased proportions of microglia co-expressing Arg1 and Iba1 and levels of TGF-β and IL-10. ATP reversed the effects of Zhuang medicine Shuanglu Tongnao Formula on microglial polarization and neuroinflammation in IS rats. Conclusion Zhuang medicine Shuanglu Tongnao Formula may promote the transformation of microglia from M1 type to M2 type by inhibiting the P2X7R/NLRP3 pathway, thereby improving neuroinflammation in IS rats.
Animals ; NLR Family, Pyrin Domain-Containing 3 Protein/metabolism* ; Receptors, Purinergic P2X7/metabolism* ; Male ; Drugs, Chinese Herbal/pharmacology* ; Rats ; Ischemic Stroke/pathology* ; Rats, Sprague-Dawley ; Disease Models, Animal ; Signal Transduction/drug effects* ; Neuroinflammatory Diseases/metabolism* ; Tumor Necrosis Factor-alpha/metabolism* ; Nitric Oxide Synthase Type II/metabolism* ; Interleukin-10/metabolism* ; Brain Ischemia/drug therapy* ; Microglia/metabolism*

OBJECTIVE: To illustrate the role of dehydrocorydaline (DHC) in chronic constriction injury (CCI)-induced neuropathic pain and the underlying mechanism. METHODS: C57BL/6J mice were randomly divided into 3 groups by using a random number table, including sham group (sham operation), CCI group [intrathecal injection of 10% dimethyl sulfoxide (DMSO)], and CCI+DHC group (intrathecal injection of DHC), 8 mice in each group. A CCI mouse model was conducted to induce neuropathic pain through ligating the right common sciatic nerve. On day 14 after CCI modeling or sham operation, mice were intrathecal injected with 5 µL of 10% DMSO or 10 mg/kg DHC (5 µL) into the 5th to 6th lumbar intervertebral space (L5-L6). Pregnant ICR mice were sacrificed for isolating primary spinal neurons on day 14 of embryo development for in vitro experiment. Pain behaviors were evaluated by measuring the paw withdrawal mechanical threshold (PWMT) of mice. Immunofluorescence was used to observe the activation of astrocytes and microglia in mouse spinal cord. Protein expressions of inducible nitric oxide synthase (iNOS), tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6), phosphorylation of N-methyl-D-aspartate receptor subunit 2B (p-NR2B), and NR2B in the spinal cord or primary spinal neurons were detected by Western blot. RESULTS: In CCI-induced neuropathic pain model, mice presented significantly decreased PWMT, activation of glial cells, overexpressions of iNOS, TNF-α, IL-6, and higher p-NR2B/NR2B ratio in the spinal cord (P<0.05 or P<0.01), which were all reversed by a single intrathecal injection of DHC (P<0.05 or P<0.01). The p-NR2B/NR2B ratio in primary spinal neurons were also inhibited after DHC treatment (P<0.05). CONCLUSION An intrathecal injection of DHC relieved CCI-induced neuropathic pain in mice by inhibiting the neuroinflammation and neuron hyperactivity.
Animals ; Neuralgia/etiology* ; Mice, Inbred C57BL ; Analgesics/pharmacology* ; Neuroinflammatory Diseases/pathology* ; Constriction ; Male ; Receptors, N-Methyl-D-Aspartate/metabolism* ; Nitric Oxide Synthase Type II/metabolism* ; Mice, Inbred ICR ; Microglia/pathology* ; Spinal Cord/drug effects* ; Female ; Mice ; Tumor Necrosis Factor-alpha/metabolism* ; Disease Models, Animal ; Constriction, Pathologic/complications* ; Interleukin-6/metabolism* ; Astrocytes/metabolism* ; Chronic Disease ; Neurons/metabolism*

OBJECTIVES: Acute lung injury (ALI) is an acute respiratory failure syndrome characterized by impaired gas exchange. Due to the lack of effective targeted drugs, it is associated with high mortality and poor prognosis. Tripterygium wilfordii (TW) has demonstrated anti-inflammatory activity in the treatment of various diseases. This study aims to investigate the effects and underlying mechanisms of TW on myeloid-derived suppressor cells (MDSCs) in ALI, providing experimental evidence for TW as a potential adjuvant therapy for ALI. METHODS: Eighteen specific pathogen-free (SPF) C57BL/6 mice were randomly divided into normal control (NC; intranasal saline), lipopolysaccharide (LPS; 5 mg/kg intranasally to induce ALI), and LPS+TW (50 mg/kg TW by gavage on the first day of modeling, followed by 5 mg/kg LPS intranasally to induce ALI) groups (n=6 each). Lung injury and edema were assessed by histopathological scoring and wet-to-dry weight ratio. Cytokine levels [interleukin (IL)-1β, IL-6, IL-18, tumor necrosis factor-α (TNF-α)] in lung tissue lavage fluid were measured by enzyme-linked immunosorbent assay (ELISA). Flow cytometry was used to assess the proportions of MDSCs, polymorphonuclear MDSCs (PMN-MDSCs), and monocytic MDSCs (M-MDSCs) in bone marrow, spleen, peripheral blood, and lung tissue, as well as reactive oxygen species (ROS) levels in lung tissues. Messenger RNA (mRNA) expression levels of inducible nitric oxide synthase (iNOS) and arginase-1 (ARG-1) in lung tissues were determined by real-time fluorescence quantitative polymerase chain reaction (RT-qPCR). PMN-MDSCs sorted from the lungs of LPS-treated mice were co-cultured with splenic CD3⁺ T cells and divided into NC, triptolide (TPL)-L, and TPL-H groups, with bovine serum albumin, 25 nmol/L TPL, and 50 nmol/L TPL, respectively. Flow cytometry was used to detect the effect of PMN-MDSCs on T-cell proliferation, and RT-qPCR was used to measure iNOS and ARG-1 mRNA expression. RESULTS: Compared with the NC group, the LPS group showed marked lung pathology with significantly increased histopathological scores and wet-to-dry ratios (both P<0.001). TW treatment significantly alleviated lung injury and reduced both indices compared with the LPS group (both P<0.05). Cytokine levels were significantly decreased in the LPS+TW group compared with the LPS group (all P<0.001). The proportions of MDSCs in CD45⁺ cells from spleen, bone marrow, peripheral blood, and lung, as well as PMN-MDSCs from spleen, peripheral blood, and lung, were significantly reduced in the LPS+TW group compared with the LPS group (all P<0.05), accompanied by reduced ROS levels in lung tissues (P<0.001). iNOS and ARG-1 mRNA expression in lung tissues was significantly lower in the LPS+TW group than in the LPS group (both P<0.001). In vitro, compared with the TPL-L group, the TPL-H group showed significantly increased CD3⁺ T-cell proliferation (P<0.001), and decreased iNOS and ARG-1 mRNA expression (all P<0.05). CONCLUSIONS TW alleviates the progression of LPS-induced ALI in mice, potentially by reducing the proportion of MDSCs in lung tissues and attenuating the immunosuppressive function of PMN-MDSCs.
Animals ; Acute Lung Injury/chemically induced* ; Myeloid-Derived Suppressor Cells/cytology* ; Tripterygium/chemistry* ; Mice, Inbred C57BL ; Mice ; Cell Differentiation/drug effects* ; Male ; Lipopolysaccharides ; Nitric Oxide Synthase Type II/genetics* ; Cytokines/metabolism* ; Reactive Oxygen Species/metabolism* ; Diterpenes/pharmacology* ; Epoxy Compounds ; Phenanthrenes

OBJECTIVES: The integrated endoplasmic reticulum stress inhibitor (ISRIB) is a selective inhibitor of the protein kinase R-like endoplasmic reticulum kinase (PERK) signaling pathway within endoplasmic reticulum stress (ERS) and can improve spatial and working memory in aged mice. Although ERS and oxidative stress are tightly interconnected, it remains unclear whether ISRIB alleviates cognitive impairment by restoring the balance between ERS and oxidative stress. This study aims to investigate the effects and mechanisms of ISRIB on lipopolysaccharide (LPS)-induced cognitive impairment in mice. METHODS: Eight-week-old male ICR mice were randomly divided into 3 groups: Normal saline (NS) group, LPS group, and ISRIB+LPS group. NS and LPS groups received daily intraperitoneal injections of normal saline for 7 days; on day 7, LPS group mice received intraperitoneal LPS (0.83 mg/kg) to establish a cognitive impairment model. ISRIB+LPS group received ISRIB (0.25 mg/kg) intraperitoneally for 7 days, with LPS injected 30 minutes after ISRIB on day 7. Cognitive ability was evaluated by the novel place recognition test (NPRT). Real-time fluorogenic quantitative PCR (RT-qPCR) was used to detect changes in nitric oxide synthase (NOS), superoxide dismutase-1 (SOD-1), and catalase (CAT) gene expression in the hippocampus and prefrontal cortex. Oxidative stress markers malondialdehyde (MDA), glutathione (GSH), and oxidized glutathione (GSSG), were measured in hippocampal and prefrontal cortex tissues. RESULTS: Compared with the NS group, mice in LPS group showed a significant reduction in novel place recognition ratio, upregulation of hippocampal NOS-1 and NOS-2 mRNA, downregulation of SOD-1 and CAT mRNA, increased MDA and GSSG, decreased GSH, and reduced GSH/GSSG ratio (all P<0.05). Compared with the LPS group, mice in ISRIB+LPS group exhibited significantly improved novel place recognition, downregulated NOS-1 and NOS-2 mRNA, upregulated SOD-1 and CAT mRNA, decreased MDA and GSSG, increased GSH, and an elevated GSH/GSSG ratio in the hippocampus (all P<0.05). No significant changes were observed in the prefrontal cortex. CONCLUSIONS ISRIB improves LPS-induced cognitive impairment in mice by restoring the oxidative/antioxidant balance in the hippocampus.
Animals ; Lipopolysaccharides ; Male ; Mice, Inbred ICR ; Cognitive Dysfunction/drug therapy* ; Mice ; Oxidative Stress/drug effects* ; Endoplasmic Reticulum Stress/drug effects* ; Hippocampus/drug effects* ; Nitric Oxide Synthase Type II/genetics* ; Guanidines/pharmacology* ; eIF-2 Kinase/antagonists & inhibitors* ; Signal Transduction/drug effects* ; Superoxide Dismutase/metabolism*

OBJECTIVES: To investigate the effect of high glucose on macrophage polarization and the role of immune-responsive gene 1 (IRG1) in mediating its effect. METHODS: RAW264.7 cells were transfected with IRG1-overexpressing plasmid or IRG1 siRNA via electroporation and cultured in either normal or high glucose for 72 h to observe the changes in cell viability and morphology using CCK-8 assay and phase contrast microscopy. The protein levels of IRG1, iNOS, Arg-1, IL-1β and IL-10 in the treated cells were detected with Western blotting, and the fluorescence intensities of iNOS and Arg-1 were detected using immunofluorescence assay. The protein levels of IL-1β and IL-10 in the culture medium were determined with ELISA. RESULTS: High glucose exposure significantly reduced IRG1 and Arg-1 expressions, increased iNOS and IL-1β expressions and IL-1β secretion, and decreased IL-10 level in RAW264.7 cells. Transfection with the IRG1-overexpressing plasmid provided the cells with obvious resistance to high glucose-induced changes in iNOS, Arg-1, IL-1β and IL-10, whereas IRG1 knockdown further enhanced the effects of high glucose exposure on Arg-1 expression and the expression and secretion of IL-10. CONCLUSIONS High glucose promotes M1 polarization of the macrophages possibly through a mechanism to inhibit the expression of IRG1 protein, thus leading to chronic inflammatory response.
Animals ; Mice ; Macrophages/drug effects* ; Glucose/pharmacology* ; Interleukin-10/metabolism* ; Nitric Oxide Synthase Type II/metabolism* ; RAW 264.7 Cells ; Interleukin-1beta/metabolism* ; Arginase/metabolism* ; RNA, Small Interfering/genetics* ; Transfection ; Inflammation

OBJECTIVE: To explore the effects of Qiwei No.3 combined with sildenafil on Rho kinase activity and AKT/eNOS pathways in the penile cavernous tissue of male rats with diabetic erectile dysfunction (DED). METHODS: We constructed a model of DED in 24 SD male rats by intraperitoneal injection of streptozotocin solution and injecting apomorphine into the neck after 8 weeks of feeding, equally randomized the model rats into a model control (MC), a sildenafil (S), a low-dose Qiwei No.3 combined with sildenafil (LQ+S) and a high-dose Qiwei No.3 combined with sildenafil (HQ+S) group, and took another 6 normal male rats as blank controls (BC). We treated intragastrically the animals in the BC and MC groups with normal saline, and those in the S, LQ+S and HQ+S groups with sildenafil (5 mg/kg/d), Qiwei No.3 (10 g/kg/d) + sildenafil (5mg/kg/d), and Qiwei No.3 (20g/kg/d) + sildenafil (5mg/kg/d), respectively. After 6 weeks of treatment, we recorded the number of penile erections of all the rats by injecting apomorphine into the neck, and measured the activity of Rho kinase and expressions of p-AKT and eNOS proteins in the corpus cavernosum by Western blot. RESULTS: Compared with the blank controls, all the DED model rats showed evidently elevated blood glucose and reduced body weight. The number of penile erections was significantly increased in the S, LQ+S and HQ+S groups in comparison with that in the model controls (P< 0.05), even higher in the HQ+S than in the S group (P< 0.05). The activity of Rho kinase in the penile cavernosum was significantly higher in the MC than in the BC group (P<0.05), but lower in the HQ+S than in the S group (P< 0.05). No statistically significant difference was observed in the expression level of the p-AKT protein in the penile cavernosum among the five groups of rats (P > 0.05). The expression of eNOS was remarkably up-regulated in the BC and HQ+S groups (P< 0.05) compared with that in the MC group, even more significantly in the HQ+S than in the LQ+S and S groups (P< 0.05). CONCLUSION The combination of high-dose "Qiwei No. 3" and sildenafil can improve erectile function in DED rats, which may be attributed to its effect of releasing more nitric oxide (NO) by inhibiting the activity of Rho kinase and up-regulating the expression of the e-NOS protein.
Animals ; Male ; Sildenafil Citrate ; Rats ; rho-Associated Kinases/antagonists & inhibitors* ; Rats, Sprague-Dawley ; Penis/drug effects* ; Erectile Dysfunction/etiology* ; Proto-Oncogene Proteins c-akt/metabolism* ; Nitric Oxide Synthase Type III/metabolism* ; Diabetes Mellitus, Experimental/complications* ; Drugs, Chinese Herbal/therapeutic use*

Objective: Antimony (Sb) has recently been identified as a novel nerve poison, although the cellular and molecular mechanisms underlying its neurotoxicity remain unclear. This study aimed to assess the effects of the nuclear factor kappa B (NF-κB) signaling pathway on antimony-induced astrocyte activation. Methods: Protein expression levels were detected by Western blotting. Immunofluorescence, cytoplasmic and nuclear fractions separation were used to assess the distribution of p65. The expression of protein in brain tissue sections was detected by immunohistochemistry. The levels of mRNAs were detected by Quantitative real-time polymerase chain reaction (qRT-PCR) and reverse transcription-polymerase chain reaction (RT-PCR). Results: Antimony exposure triggered astrocyte proliferation and increased the expression of two critical protein markers of reactive astrogliosis, inducible nitric oxide synthase (iNOS) and glial fibrillary acidic protein (GFAP), indicating that antimony induced astrocyte activation Conclusion Antimony activated astrocytes by activating the NF-κB signaling pathway.
Animals ; Antimony/toxicity* ; Astrocytes/metabolism* ; Cell Line, Tumor ; Cell Proliferation/drug effects* ; Glial Fibrillary Acidic Protein/metabolism* ; MAP Kinase Kinase Kinases ; Male ; Mice, Inbred ICR ; NF-kappa B/metabolism* ; Nitric Oxide Synthase Type II/metabolism* ; Rats ; Signal Transduction/drug effects*

OBJECTIVE: To investigate the effects of vitamin E on the respiratory function impairment in rats with chronic obstructive pulmonary disease (COPD) after exposed to high temperature and PM. METHODS: Fifty-four 7-week-old SPF male Wistar rats were randomly divided into 9 experimental groups (n=6). The rat COPD model was established by lipopolysaccharide (LPS) and smoke exposure. After modeled, the rats were tracheal instilled with PM (0 mg/ml, 3.2 mg/ml) and intraperitoneally injected with vitamin E at the dose of 40 mg/kg (20 mg/ml). Part of rats (high temperature groups) were then exposed to high temperature (40℃), once (8 h) a day for three consecutive days. After the last exposure, the lung function of rats was detected. The expression levels of inducible nitric oxide synthase (iNOS), tumor necrosis factor-α (TNF-α) and monocyte chemotactic protein-1 (MCP-1) were detected by corresponding ELISA kits. RESULTS: Compared with the control group, exposure of high temperature and PM could inhibit the lung function of COPD rats significantly (P＜0.05); the level of MCP-1 was increased significantly in PM-exposure groups (P＜0.05); iNOS was increased significantly in the groups of high temperature (P＜0.05). Compared with the single-PM exposure groups, TNF-α in lung was decreased in the normal temperature health group and high temperature COPD group (P＜0.05) after treated with vitamin E; MCP-1 was decreased in all vitamin E-treated groups (P＜0.05); the decreased iNOS only appeared in the group of high temperature with vitamin E treatment. CONCLUSION High temperature and PM could aggravate the inflammation of COPD rats. As an antioxidant, vitamin E may protect the lung from the damage effects.
Animals ; Chemokine CCL2 ; metabolism ; Hot Temperature ; adverse effects ; Lung ; physiopathology ; Male ; Nitric Oxide Synthase Type II ; metabolism ; Particulate Matter ; adverse effects ; Pulmonary Disease, Chronic Obstructive ; drug therapy ; Random Allocation ; Rats ; Rats, Wistar ; Tumor Necrosis Factor-alpha ; metabolism ; Vitamin E ; pharmacology

OBJECTIVE: To investigate the effects of apple polyphenols on pulmonary vascular remodeling in rats with pulmonary arterial hypertension and its mechanism. METHODS: Rats were randomly divided into 4 groups:control (Con) group, monocrotaline (MCT) group, apple polyphenol (APP) group,monocrotaline + apple polyphenol (MCT+APP) group. In Con group, rats received a subcutaneous injection of physical saline. In APP group, rats received intraperitoneal injection of 20 mg/kg APP, every other day. In MCT group, rats received a single subcutaneous injection of MCT(60 mg/kg). In MCT+APP group, rats received subcutaneous injection of 60 mg/kg MCT followed by an intraperitoneal injection of 20 mg/kg APP every other day. All the disposal lasted 3 weeks. Then the PAH-relevant indicators, such as mean pulmonary artery pressure(mPAP), pulmonary vascular resistance(PVR), right ventricular hypertrophy index (RVHI) ,wall thickness (WT%) and wall area (WA%) were tested. After that, the inflammatory pathway related indicators, such as interleukin1(IL-1),interleukin1(IL-6), tumor necrosis factor α(TNF-α), cyclooxygenase 2(COX-2) and myeloperoxidase(MPO) in pulmonary tissue and free intracellular Ca in pulmonary smooth muscle cell(PASMC), content of eNOS and NO in endothelial cells were determined. RESULTS: Compared with the control group, the levels of mPAP, PVR, RVHI, WA%, WT%, and IL-1, IL-6, TNF-α, COX-2, MPO in tissue and the expression of Ca in PASMC of MCT group were increased significantly, while the contents of eNOS and NO in endothelial cells were decreased significantly (P＜0.05). Compared with the MCT group, the apple polyphenol treatment could improve the above mentioned situation, and the COX-2 and Ca indicators of the apple polyphenol treatment group were decreased significantly (P＜0.05). CONCLUSION MCT can increase COX-2 expression and intracellular Ca in pulmonary artery smooth muscle cells, decrease the contents of eNOS and NO in endothelial cells, while apple polyphenols can significantly inhibit these effects.
Animals ; Calcium ; metabolism ; Cyclooxygenase 2 ; metabolism ; Cytokines ; metabolism ; Malus ; chemistry ; Monocrotaline ; Nitric Oxide ; metabolism ; Nitric Oxide Synthase Type III ; metabolism ; Polyphenols ; pharmacology ; Pulmonary Artery ; drug effects ; pathology ; Random Allocation ; Rats ; Vascular Remodeling ; drug effects