EFFECTS OF GINSENG TREATMENT ON NEUTROPHIL CHEMILUMINESCENCE AND IMMUNOGLOBULIN-G SUBCLASSES IN A RAT MODEL OF CHRONIC PSEUDOMONAS-AERUGINOSA PNEUMONIA

Chronic Pseudomonas aeruginosa lung infection in cystic fibrosis (CF) patients is almost impossible to eradicate with antibiotic treatment, In the present study, the effects of treatment with the Chinese herbal medicine ginseng on blood polymorphonuclear leukocyte (PMN) chemilumi nescence and serum specific antibody responses were studied in a rat m odel of chronic P, aeruginosa pneumonia mimicking CF. An aqueous extra ct of ginseng was administered by subcutaneous injection at a dosage o f 25 mg/kg of body weight/day for 2 weeks, Saline was used as a contro l. Two weeks after the start of ginseng treatment, significantly incre ased PMN chemiluminescence (P less than or equal to 0.001) and a decre ased level in serum of immunoglobulin G (IgG) against P. aeruginosa (P < 0.05) were found, Furthermore, a higher IgG2a level (P < 0.04) but lower IgG1 level (P < 0.04) were found in the ginseng-treated infected group than in the control group. In the ginseng-treated group the mac roscopic lung pathology was milder (P = 0.0003) and the percent PMNs i n the cells collected by bronchoalveolar lavage was lower (P = 0.0006) than in the control group. However, the alveolar macrophage (AM) chem iluminescence values were not significantly different in the two group s infected with P. aeruginosa, The differences between the ginseng-tre ated noninfected rats and the control group (without P. aeruginosa lun g infection) for the PMN chemiluminescence and AM chemiluminescence we re not significant. These results suggest that ginseng treatment leads to an activation of PMNs and modulation of the IgG response to P. aer uginosa, enhancing the bacterial clearance and thereby reducing the fo rmation of immune complexes, resulting in a milder lung pathology, The changes in IgG1 and IgG2a subclasses indicate a possible shift from a Th-2-like to a Th-1-like response. These findings indicate that the t herapeutic effects of ginseng may be related to activation of a Th-1 t ype of cellular immunity and down-regulation of humoral immunity.