豚鼠肺组织糖皮质激素受体在哮喘发病过程中的变化及与磷脂酶A_2的关系

A study on changes of glucocorticoid receptor andphospholipase A_2 in guinea pig asthma models

对豚鼠哮喘模型进行哮喘发作第１、３、７、１４天肺组织糖皮质激素受体（ＧＲ）及磷脂酶Ａ＿２（ＰＬＡ＿２）水平的测定，结果显示，从哮喘发作第３天起，ＧＲ最大特异结合量（Ｂ＿（ｍａｘ））及平衡解离常数（ｋｄ）值较对照组显著下降（Ｐ＜０．０１），而ＰＬＡ＿２活力则自哮喘发作第１禾起显著升高（Ｐ＜０．０１）。ＧＲＢ＿（ｍａｘ）与ＰＬＡ＿２在发病过程中呈线性负相关（ｒ＝－０．９０２３，Ｐ＜０．０５）。认为ＧＲ数量降低可能与哮喘应激状态下ＧＲ向胞核内移增多有关，ＧＲＫｄ值降低即ＧＲ与糖皮质激素亲和力增高是动物机体对ＧＲ数量减少的代偿性反应，但这种代偿尚不足以抑制ＰＬＡ＿２活力的病理性增高。

n this study we determined the glucocorticoid re-ceptor(GR)level(using￣3 H-dexamethasone as aligand)and phospholipase A_2(PLA_2 ) activity of lungtissue in guinea pig asthma models at lst , 3rd , 7thand 14th day of asthma attacks.The results showedthat the GR maximal binding capacity(B_(max) , fmol/mgpro.)were 54. 36±26. 57, 30. 99±10.01,19. 40±10. 06 , and 29. 16 ±11. 35; GR dissociation constant(Kd,nmol/L)were 12. 73±4. 06,8.28±3.23,5. 70±2. 91 , and 6. 40±2. 64 respectively;and PLA_2 acti-sis(U were 181.58±41.50,239.80±61.15.243.08± 31. 35 ,and235.71±86. 13respectively.The GR B_(max), Kd and PLA_2 of actisis control groupwere 61.48±27. 60(fmol/mg pro.), 13. 11± 2.88(nmol/L) , 81. 06±15. 97(U).The GR B_(max)and Kdof asthmatic animals decreased significantly since the3rd day,but the PLA_2 activity increased significantlysince the lst day as compared to the control group(P<0. 01). The changes of GR B_(max)had significant nega-tive correlation with those of the PLA_2 activity(r=-0.9023.P<0.05).Them mechanism of the GR and PLA_2 actisis changes of asthma animal models werediscussed.