Effect of nebulized ketamine on the airway inflammation in a rat model of asthma / 中华麻醉学杂志

ABSTRACT

Objective To investigate the effect of nebulized ketamine inhalation on the airway inflammation in a rat model of asthma and to elucidate the possible mechanism. Methods Forty male SD rats weighing 160-200 g were randomly assigned to one of five group with eight animals in each group Ⅰ control group (N);Ⅱ asthama group(A)and Ⅲ, Ⅳ,Ⅴ ketamine pretreatment groups ( K1, K2, K3 ). In group Ⅱ-Ⅴ asthma was induced in two steps; (1) the animals received subcutaneous injection of ovalbumia (OA) 1 mg and aluminum hydroxide 160 mg in 1 ml of normal saline (NS) and intraperitoneal devitalized Bordetella pertussis 6 ?109 in 1 ml NS;(2) 2 weeks later asthma was elicited by nebulized 1% OA in NS for 20 min.In group K1,K2 and K3 the sensitized animals were exposed to nebulized ketamine 12.5 mg?ml-1(K1) ,25 mg?ml-1(K2) or 50mg?ml-1(K3) for 20 min,25 min before challenge with nebulized OA.Blood samples were taken and lymphocytes were isolated and cytosol and membrane PKC fractions extracted by centrifugation and PKC acdvities were determined. The right lung was removed for microscopic examination. Results There were acute inflammatoty changes in the airway in group A and there was no significance in the inflammatory cell infiltration in and local damage to the airway between group A and K1. Compared with group A there was significantly less inflammation in the bronchial subnucosa and alveolor septum and no damage was observed in group K2 and K3. The total (PKCT ), cytosol (PKCC) and membrane ( PKCM ) PKC activity and percentage of membrane PKC [( PKCM/PKCT ( % ) ] were significantly higher in group A,K1 and K3 than those in group N ( P