The levels of platelet-activating factor and nitric oxide synthase in bronchial asthma at high altitude

Abstract

To investigate levels of platelet- activating factor (PAF) and nitric oxide synthase(NOS) in plateau asthma. Peripheral blood platelet was counted and the serum level of PAF, TNOS, iNOS and cNOS were measured by ELISA in patients with asthma who lived at plateau and at plain respectively and healthy volunteers as the plan control group and in plateau control group. The data were expressed as x(-) ± s, and one way ANOVA was used for comparison of means; The correlation of 2 variables was estimated by Spearson rank correlation coefficience. The PLT count was (166 ± 46) × 10(9)/L in the plateau asthma group and (140 ± 47) × 10(9)/L in the plateau control group, and both were significantly lower than those of the plain control group [(237 ± 98) × 10(9)/L] and the plan asthma group [(232 ± 71) × 10(9)/L, P < 0.01]. The levels of serum PAF in the asthma groups were higher than those of the control groups. The level of serum PAF in the plan asthma group [(877 ± 297) pg/L], was not only higher than that in the plan control group [(290 ± 132) pg/L], but also higher than that in the plateau asthma group [(429 ± 254) pg/L]; the difference being significant among groups (F = 66.08, P < 0.01). The PLT count showed a positive correlation with the level of PAF (r = 0.283, P < 0.01). The levels of TNOS, iNOS, and cNOS were not statistically different (P > 0.05) between the plain control group and the plateau control group. The levels of TNOS, iNOS and cNOS in plain asthmatic group [(36.2 ± 23.0), (20.3 ± 14.7) and (15.9 ± 8.4) U/ml respectively] were significantly higher than those of the plateau control [(11.9 ± 1.3), (9.4 ± 1.5) and (4.9 ± 0.5) U/ml] and the plateau asthmatic [(21.0 ± 2.3), (15.4 ± 2.5) and (5.3 ± 0.8) U/ml] groups(F = 17.197, 8.258, 34.250, respectively, P < 0.01). The increase of iNOS level was more significant. Asthma in plateau area is associated with decrease of the levels of PLT, PAF and NOS.