Investigating the mechanism of antihypertensive actions of medicinal plants using some animal models

As the search for, and development of new drugs continues, drug companies engage in the large-scale pharmacological screening of medicinal plants. This creates the need to elucidate the mechanism of action of medicinal plants found to possess biological activity as a means of deriving their full therapeutic potential. This research was carried out to investigate the mechanism of the antihypertensive action of Vernonia amygdalina, Ocimum gratissimum, and Pterocarpus erinaceus using animal models. The dried 70% ethanolic extracts of the plants were prepared at varying concentrations ranging from 0.4 mg/mL to 50 mg/mL. These extracts were administered at varying doses alone and in the presence of selected antagonists like prazocin in anesthetized cat in-vivo and to rabbit jejunum and spontaneously beating guinea pig right atrium. Adrenaline and atropine were used as control drugs.The effects of these plants extracts were demonstrated on the Finkleman preparation and they were found to induce relaxation of the rabbit jejunum. They also reduced both the rate and force of contraction of spontaneously beating guinea pig's right atrium. The cardiovascular effects of the extracts were investigated on cat blood pressure. The effect of atropine tested in the presence of V. amygdalina and O. gratissimum showed a change in the pattern of induced fall in blood pressure but does block the fall in blood pressure induced by the extracts. While the exact mechanism of the antihypertensive action of these extracts has not been fully determined, the result of this research work proposes that the mechanism could either be blocking calcium channels or have direct activity on lowering blood pressure. It is therefore recommended that further studies be conducted on the extracts to better understand the mechanism of antihypertensive actions of these plants.

El biomodelo porcino en la investigación médica traslacional: del biomodelo al humano en trasplante pulmonar / The porcine biomodel in translational medical research: From biomodel to human lung transplantation

Resumen Introducción. La anatomía humana y porcina son comparables. En consecuencia, el biomodelo porcino tiene el potencial de ser implementado para entrenar al profesional quirúrgico en áreas como el trasplante de órganos sólidos. Objetivo. Describir los procedimientos y hallazgos obtenidos mediante experimentos de medicina respiratoria traslacional con biomodelos porcinos realizados en un laboratorio de experimentación animal, y hacer una revisión comparativa entre el pulmón humano y el porcino. Materiales y métodos. El experimento se llevó a cabo en nueve cerdos de raza híbrida en un laboratorio de cirugía experimental. Se estudiaron la anatomía y la histología de las vías respiratorias mediante fibrobroncoscopia, biopsia bronquial y lavado broncoalveolar. El lavado broncoalveolar se estudió con citología en base líquida y se evaluó con las coloraciones de Papanicolau y hematoxilina y eosina. Se utilizaron técnicas de patología molecular, como inmunohistoquímica, citometría de flujo y microscopía electrónica. Los cerdos se sometieron a neumonectomía izquierda con posterior implante del injerto en otro cerdo experimental. Resultados. Los estudios histopatológicos y moleculares evidenciaron un predominio de macrófagos alveolares (98 %) y linfocitos T (2 %) en el lavado broncoalveolar porcino. En los estudios del parénquima pulmonar porcino se encontró tejido linfoide hiperplásico asociado a las paredes bronquiales. La microscopía electrónica evidenció linfocitos T dentro del epitelio y el diámetro de las cilias porcinas fue similar al de las humanas. Conclusiones. El biomodelo porcino es viable en la investigación traslacional para el entendimiento de la anatomía del sistema respiratorio y el entrenamiento en trasplante pulmonar. La implementación de este modelo experimental podría fortalecer los grupos que planean implementar un programa institucional de trasplante pulmonar en humanos.

Abstract Introduction: Human and porcine anatomy are comparable. In consequence, the porcine biomodel has the potential to be implemented in the training of surgical professionals in areas such as solid organ transplantation. Objectives: We described the procedures and findings obtained in the experiments of translational respiratory medicine with the porcine biomodel, within an experimentation animal laboratory, and we present a comparative review between human and porcine lung. Materials and methods: The experiment was done in nine pigs of hybrid race within a laboratory of experimental surgery. The anatomy and histology of the respiratory tract were studied with fibrobronchoscopy, bronchial biopsy and bronchoalveolar lavage. The bronchoalveolar lavage was studied with liquid-based cytology and assessed with Papanicolau and hematoxylin-eosin staining. Molecular pathology techniques such as immunohistochemistry, flow cytometry, and electronic microscopy were implemented. The pigs were subjected to left pneumonectomy with posterior implantation of the graft into another experimental pig. Results: Histopathologic and molecular studies evidenced predominance of alveolar macrophages (98%) and T-lymphocytes (2%) in the porcine bronchoalveolar lavage. Studies on the porcine lung parenchyma revealed hyperplasic lymphoid tissue associated with the bronchial walls. Electronic microscopy evidenced the presence of T-lymphocytes within the epithelium and the cilia diameter was similar to the human. Conclusions: The porcine biomodel is a viable tool in translational research applied to the understanding of the respiratory system anatomy and the training in lung transplantation. The implementation of this experimental model has the potential to strength the groups who plan to implement an institutional program of lung transplantation in humans.

Effect of Electro-acupuncture on Behavior Alterations in Mice with Isoflurane-induced Alzheimer's Disease and Its Mechanism / 广州中医药大学学报

Objective To investigate the effect of electro-acupuncture on behavior alterations,the expression of amyloid precursor protein(APP),amyloid β-protein(Aβ) proteins and neuroapoptosis in the cerebral cortex in the APPswe/PS1dE9 double transgenic mice with Alzheimer's disease (AD) induced by isoflurane.Methods Sixmonth-old AD mice and wild-type mice at the same age were randomly divided into wile-type control group,AD group,isoflurane group,electro-acupuncture group (N =8).The mice were given pretreatment with electro-acupuncture at Baihui(GV20) acupoint and Yongquan(KI 1) acupoint once a day for 3 successive days,15 min each time.And then the mice in electro-acupuncture group and isoflurane group were exposed to a box full of 1.2％ isoflurane for 4 hours.Morris water maze was used to test the learning and memory abilities of the mice,Western blotting method was used to detect the expression of APP-C83,APP-C99 and Aβ,and terminal deoxynucleotidyl transferase(TdT)-mediated dUTP nick end labeling(TUNEL) was used to detect neuroapoptosis in the cerebral cortex.Results The escape latency of AD group was longer than that of wild-type mice group(P＜0.05),and the latency of isoflurane group was longer than that of AD group (P ＜ 0.05),while the latency of electro-acupuncture group was shorter than that of isoflurane group(P ＜ 0.05).The percentage of retention time in the target quadrant and the times for crossing the target quadrant in isoflurane group were lower than those of AD group (P ＜ 0.05),but were higher in electro-acupuncture group than those in isoflurane group (P ＜ 0.05).APPC83 expression level in isoflurane group was significantly lower than that in AD group (P ＜ 0.05),while APP-C83 expression level in electro-acupuncture group was higher than that in isoflurane group (P ＜ 0.05).APP-C99 expression level in isoflurane group was significantly higher than that in AD group (P ＜ 0.05),and APP-C99 expression level in electro-acupuncture group was lower than that in isoflurane group (P ＜ 0.05).The cortical apoptosis index in isoflurane group was significantly higher than that in AD group (P ＜ 0.05),and the cortical apoptosis index in electro-acupuncture group was lower than that in isoflurane group (P ＜ 0.05).The expression level of Aβ in AD group,isoflurane group and electro-acupuncture group was significantly higher than wild-type control group (P ＜ 0.05).Conclusion Electro-acupuncture can relieve the AD-like neurotoxicity induced by isoflurane and inhibit the decline of learning and memory abilities of AD mice,and the mechanism is probably related with suppressing the overexpression of APP-C99 and reducing the production and accumulation of Aβ,thereby alleviating the neuroapoptosis.

Estandarización de un modelo para inducir obesidad en ratas / Standardization of model to induce obesity in rats

Fundamento: La obesidad es un factor de riesgo para múltiples enfermedades. Existen diversos modelos en ratas para inducir obesidad. Los modelos genéticos y la obesidad inducida por la dieta son costosos. Dentro de los modelos hipotalámicos de obesidad está el que se logra mediante la administración de glutamato monosódico en período neonatal. Esta sustancia no es costosa y produce las alteraciones metabólicas más importantes que se ven en la obesidad humana. Objetivo: seleccionar un esquema de tratamiento adecuado para inducir obesidad con glutamato monosódico en ratas Wistar en periodo neonatal. Métodos: se administró glutamato monosódico a ratas Wistar en período neonatal, siguiendo tres esquemas diferentes de tratamiento (con cinco, siete y diez dosis), a 4mg/g/día, y mediante dos vías de administración: subcutánea e intraperitoneal. A los controles se les administró cloruro de sodio al 0,9 %. Para realizar el diagnóstico de obesidad, a los 90 días se evaluaron las variables: peso, longitud hocico-ano e índice de Lee. Resultados: con todos los esquemas de tratamientos ensayados, la longitud hocico-ano resultó diferente estadísticamente entre el grupo tratado con glutamato monosódico y los controles. El 100 % de las ratas que alcanzaron la adultez, inyectadas con glutamato monosódico, se hicieron obesas. Conclusión: el esquema con cinco dosis de glutamato monosódico, aplicado en días alternos por vía subcutánea, fue seleccionado por desarrollarse la obesidad con menor manipulación y menor porcentaje de muertes neonatales.

Background: Obesity is a risk factor for multiple diseases. There are various rat models to induce this condition. Genetic models and diet-induced obesity are expensive. Within the models of hypothalamic obesity, there is one achieved by the administration of monosodium glutamate during the neonatal period. This substance is not expensive and causes the major metabolic alterations observed in human obesity. Objective: to select an appropriate treatment scheme to induce obesity with monosodium glutamate during neonatal period. Methods: monosodium glutamate was administered to Wistar rats during the neonatal period, using three different treatment schemes (with five, seven and ten doses) of 4mg/g/day through two routes of administration: subcutaneous and intraperitoneal routes. Controls were administered 0.9% sodium chloride. To establish the diagnosis of obesity, the following variables were measured at 90 days: weight, snout-anus length and Lee index. Results: with all treatment schemes tested, snout-anus length was statistically different between the group treated with monosodium glutamate and the controls group. 100% of the rats that reached adulthood injected with monosodium glutamate was obese. Conclusion: the scheme of five doses of monosodium glutamate, applied subcutaneously on alternate days, was selected as obesity is obtained with less handling and lower percentage of neonatal deaths.

Importância dos estudos pré-clínicos em animais de experimentação para a cardiologia intervencionista: [revisão] / The importance of pre-clinical animal testing in interventional cardiology: [review]

O tratamento da doença cardiovascular mudou radicalmente nas últimas duas décadas, proporcionando aos pacientes uma sobrevida maior e melhor qualidade de vida. Grande parte desse sucesso deve-se à introdução de novas terapias. Em nenhuma outra área essa mudança foi mais evidente do que na cardiologia intervencionista, pois nos últimos vinte anos as intervenções cardiovasculares percutâneas saíram do terreno experimental para formar a base terapêutica dos portadores de doença cardiovascular sintomática. O desenvolvimento dessas tecnologias, desde os primeiros estágios, requer a realização de estudos pré-clínicos com modelos animais. É possível compreender os mecanismos terapêuticos desses dispositivos, uma vez introduzidos na esfera clínica, comparando-se os achados das pesquisas realizadas com modelos animais com amostras de exames anatomopatológicos. Esta análise apresenta uma visão geral do papel emergente dos estudos pré-clínicos, bem como dos resultados, do desenvolvimento e da avaliação de modelos amimais, nas tecnologias de intervenção cardiovascular percutânea para tratamento de pacientes com doença cardiovascular sintomática.

The treatment of cardiovascular disease has changed dramatically over the past 2 decades, allowing patients to live longer and better quality lives. The introduction of new therapies has contributed much to this success. Nowhere has this been more evident than in interventional cardiology, where percutaneous cardiovascular intervention has evolved in the past 2 decades from a quirky experimental procedure to a therapeutic cornerstone for patients with symptomatic cardiovascular disease. The development of these technologies from the earliest stages requires preclinical experiments using animal models. Once introduced into the clinical arena, an understanding of therapeutic mechanisms of these devices can be ascertained through comparisons of animal model research findings with clinical pathological specimens. This review provides an overview of the emerging role, results of preclinical studies and development, and evaluation of animal models for percutaneous cardiovascular intervention technologies for patients with symptomatic cardiovascular disease.

Establish and evaluate allergic rhiultis model in guinea pigs with Toluene-2,4-diisocyanate / 中国医师杂志

Objective To understand the changes of allergic rhinitis from immunology,pathophysiology and morphology method were applied.Methods Toluene 2,4-diisocyanate was dissolved with florence oil to final concentration 10%,this solution was dropped into the nasal vestibules of animals to induce sensitization process.8 guinea pigs were prepared as allergic rhinitis with 10% Toluene 2,4-diisocyanate,and other 8 animals were used as blank controh.After model successfully established,the blood were obtained to determine RBC-C3b receptor rosette rate and RBC-imuuunocomplex rosette rate.The nasal mucosas were obtained from 2 groups,distribution and changes of substance P in nasal mucosa were observed with the application of immunohistochemical staining.The content of blood histamine was determined with ELASA method.The pathological changes of nasal mucosas were observed with the application of light microscope and transmission electron microscope.Results The behavior scores of the modeling animals were significantly higher than that of controls(P＜0.01).The value of RBC-C3b reeeptor rosette rate and RBC-imuuunoeomplex rosette rate of the modeling animals were significantly decreased than that of the controls(P＜0.05).Substance P presented in the normal nasal mucosal epithelial cells,epithelium cells of blood vessels,glandular cells and its duets,the staining density and the positive staining cells in the same aero in modeling group significantly increased,compared with controls.The counts of substance P-positive cells of control group were less than those of modeling group(P＜0.05).The content of blood histamine of the modeling animals were significantly increased compared with the controls(P＜0.01).The structure of false multiple coat cilium columnar epithelial cells in nasal mucosa of control group were successive,intact,and distinct.There were normal mucosal epithelium,lamina propria and submucosa.But modeling group showed that mucosal epithalamiums were damaged and shed,goblet cell proliferated,squamous metaphase,and epithelial necrosis happened,serous glands in lamina propria vigorously proliferated,blood vessels expanded,tissue edema formed,plenty of inflammatory cell such as eosinophil and mast cells were more in number and infiltrated.The structure of epithelial eells,cilia and mierotubule of nasal mucosa of control group were regular and distinct,there were abundant cellular organs in cytoplasm.Eosinophil cells were intact.But iu model group,mucosal epithalamium,cilia and its microtubule,mierovillus,goblet cell were damaged,the cell bulk and nucleus changed,mast cells and eosinophil cells changed,blood vessels expanded,serous glands vigorously proliferated.This morphological change was roughly identical to clinical manifestation of allergic rhinitis.Conclusion Toluene-2,4-diisocyanate can be used to establish allergic rhinitis model in guinea pigs,and some ehanges of the allergic rhinitis in model guinea pig were similar with clinic observation.

Evidências sorológicas e experimentais da resposta autoimune humoral contra a retina em uveites causada por Toxoplasma gondii / Experimental and serological evidence of humoral autoimmune response against retina in Toxoplasma gondii uveitis

A toxoplasmose ocular é atribuída ao parasita, mas a auto-imunidade pode participar do processo. Soros humanos com IgG positiva para T. gondii mostraram níveis altos de IgG anti-retina para diferentes antígenos, se comparados com soros negativos para T. gondii, uveítes de outras origens também tiveram títulos elevados. Hamsters imunizados e/ou infectados não mostraram estes anticorpos sem mimetismo antigênico. A retinocoroidite por Toxoplasma induz resposta humoral auto-imune contra antígenos da retina, provavelmente piorando o efeito direto do agente. Estes anticorpos podem ser usados como marcadores de doença ocular em pacientes soropositivos para toxoplasmose pela triagem de lesão ocular.

Ocular toxoplasmosis is attributed to the parasite, but autoimmunity could have a role in this process. Human sera, positive of anti-T. gondii IgG, show high levels of anti-retina IgG, measured by several antigens, as compared to T. gondii seronegative samples. Sera from patients with uveitis from other origins also had higher anti-retina abs levels. Challenged and/or immunized hamsters showed low anti-retina abs levels, without antigen mimicry. Toxoplasmic retinochoroiditis presents a humoral anti-retina abs, probably worsening the parasite direct effect. Those antibodies could be used as markers of eye involvement in toxoplasmosis seropositive patients, as a screening for eye examination.

Expression of Fas and Fas ligand and cell apoptosis in the ischemia/reperfusion-induced retina and therapeutic effects of basic fibroblast growth factor / 中华眼底病杂志

Objctive To explore the relationship between the expression of Fas/FasL and the apoptosis occurs in retinal ischemia/reperfusion injury of rats, as well as the therapeutic effects of bFGF on the ischemic retina. Methods The models of retinal ischemia/reperfusion injury was made by transient elevating introcular pressure. A total of 28 rats were divided into normal and operation group.The latter were subdivided into 1 hour, 6, 12, 24, 48 and 72 hours after reperfusion group, in which the left eyes of the rats were in the ischemia/reperfusion groups and the right ones were in the treatment groups (bFGF intracameral injection). Apoptosis was assessed by the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labelling (TUNEL) method, and the expression of Fas and Fas ligand was studied by strept avidin-biotin complex (SABC)immunohistochemistry. Results No positive cells were observed in the normal rats′ retinae, but there was a significant number of TUNEL positive cells in 6-24 hours after transient ischemia followed by a decrease at the 48th hour. The number of TUNEL positive cells reached a maximum at the 24th hour after ischemia. The expression of Fas gradually increased as early as when it was at the 6th hour, reached a peak at the 24th hour, and then decreased at the 48th hour. Similarly, the expression of Fas ligand was at peak in 24-48 hours in GCL and INL of retina. Conclusions Retinal ischemia-reperfusion after transient elevated IOP induced apoptosis of cells in the retina. Fas/FasL may play an important role in the early events of the apoptotic pathways. bFGF can rescue RGCs from retinal ischemia/reperfusion injury through downregulation of the expression of Fas/FasL and may represent an important mechanism for therapeutic neuroprotection.