Development of an experimental model of neutrophilic pulmonary response induction in mice

BACKGROUND: Several lung diseases are characterized by a predominantly neutrophilic inflammation. A better understanding of the mechanisms of action of some drugs on the airway inflammation of such diseases may bring advances to the treatment. OBJECTIVE: To develop a method to induce pulmonary neutrophilic response in mice, without active infection. METHODS: Eight adult Swiss mice were used. The study group (n = 4) received an intranasal challenge with 1 x 10(12) CFU/ml of Pseudomonas aeruginosa (Psa), frozen to death. The control group (n = 4) received an intranasal challenge with saline solution. Two days after the intranasal challenge, a bron¡choalveolar lavage (BAL) was performed with total cell and differential cellularity counts. RESULTS: The total cell count was significantly higher in the group with Psa, as compared to the control group (median of 1.17 x 10(6) and 0.08 x 10(6), respectively, p = 0.029). In addition to this, an absolute predominance of neutrophils was found in the differential cellularity of the mice that had received the Psa challenge. CONCLUSIONS: The model of inducing a neutrophilic pulmonary disease using frost-dead bacteria was successfully developed. This neutrophilic inflammatory response induction model in Swiss mice lungs may be an important tool for testing the anti-inflammatory effect of some antimicrobial drugs on the inflammation of the lower airways.

Evaluación de los mecanismos oxidativos del PMN neutrófilo de saliva de pacientes periodontalmente sanos por reducción de NBT / An evaluation of the oxidative mechanisms of salivary PMN neutrophil in saliva of periodontally healthy patients by NBT reduction

Antecedentes: en general, las enfermedades periodontales se caracterizan por cambios, tanto estructurales como bioquímicos en el ámbito tisular, y en su patogenia, por contraste de infecciones bacterianas, el neutrófilo es considerado como la célula más importante de la inmunidad innata. La importancia de esta célula radica en el hecho de estar presente en cada uno de los cuatro estadios que caracterizan el avance de la lesión, así como en los hallazgos de susceptibilidad a infecciones bacterianas recurrentes, incluyendo enfermedad periodontal, en pacientes con defectos cualitativos y cuantitativos en PMN neutrófilos de sangre periférica. Una de las alteraciones funcionales del neutrófilo asociada a la pérdida de la capacidad de defensa ejercida por esta célula contra bacterias extracelulares, la constituye el hecho de ser incapaz de acivar sus mecanismos oxidativos para producir la muerte intracelular de los microorganismos ingeridos. Objetivo: evaluar la capacidad del PMN neutrófilo de saliva y sangre periférica de pacientes periodontalmente sanos para activarse y utilizar losmecanismos microbicidas dependientes de oxígeno, para reconocer si el PMN neutrófilo, al migrar a través del surco gingival, conserva intacta su funcionalidad. Métodos: el estudio fue descriptivo comparativo, in vitro. Para su desarrollo se formaron muestras de saliva y de sangre periférica de 5 individuos. Los neutrófilos aislados fueron sometidos a activación con phorbol miristato acetato (PMA) y posteriormente a las pruebas de reducción del nitroazul de tetrazolio, el cual se puede cuantificar por observación directa al microscopio de luz. Resultados: los PMN neutrófilos obtenidos de sangre y saliva reducen el NBT en un porcentaje más ato que los PMN neutrófilos de sangre periférica, en ausencia de activación. Se encontró que los PMN neutrófilos de saliva tienen un estado de activación de base debido a su constante exposición a las bacterias de la cavidad bucal, y una vez que se activan, dichas células reducen el NBT en menor cantidad que los PMN neutrófilos de sangre periférica bajo iguales condiciones. Conclusiones: los PMN neutrófilos de saliva son células funcionales capaces de activarse, ya que mantienen intactos los mecanismos oxidativos una vez llegan a la saliva a través del surco gingival

CD44 mediates polymorphonuclear leukocyte motility on hyaluronan

To investigate the behavior of polymorphonuclear [PMN] leukocytes on the extracellular matrix carbohydrate component, hyaluronan [HA], in the presence and absence of the chemokine, interleukin-8 [IL-8]. The present study was conducted at the Department of Hematology, University of Liverpool, United Kingdom, between the period 2000 to 2001. Polymorphonuclear cells were isolated from whole venous blood using Mono-Poly-Resolving Medium. Purified PMN were added alone or with IL-8 to HA-coated plates and the behavior of these cells monitored by time-lapse video microscopy over a period of 40 minutes. For the identification of surface receptor[s] mediating PMN migration on HA, PMN were incubated with blocking and non-blocking antibodies against cluster of differentiation 44 [CD44] and Receptor for Hyaluronan Mediated Motility [RHAMM] prior to addition to HA-coated surfaces. Approximately 55% of PMN were found to interact and migrate on HA-coated plates with a mean speed of 6.4 +/= 0.7 mm/min. Addition of IL-8 reduced both the percentage moving cells [7.5%] and the average speed of the remaining moving cells [2.0 +/= 0.3 mm/min]. The inhibitory effect of IL-8 on PMN migration was associated with reorganization of the cytoplasmic fibrillar form of actin. Anti-CD44 blocking antibody substantially reduced the speed of PMN [2.5 +/= 0.9 mm/min], while non-blocking anti-CD44 and anti-RHAMM antibodies had no effect. The present study demonstrates for the first time that PMN are able to interact and migrate on the widely distributed extracellular matrix component, HA, using the cell surface receptor, CD44. Such interaction is modified by the chemokine, IL-8, in a way that optimizes the host defense against invading pathogens