IgA肾病患者肾小球胶原Ⅳ基因表达的改变

Different expressions of α2 (Ⅳ) andα3 (Ⅳ) collagenmRNAs in renal glomeruli of IgA nephropathy

应用原位逆转录－多聚酶链反应技术对７例ＩｇＡ肾病、４例系膜增殖性肾炎患者肾小球胶原Ⅳ的α２、α３亚链ｍＲＮＡ表达进行检测，同时以看家基因－３磷酸甘油醛脱氢酶表达作为内对照。结果发现，病理上呈Ⅲ级病变的ＩｇＡ肾病患者肾小球胶原Ⅳα２ｍＲＮＡ表达较Ⅱ级病变患者显著增强（ＰＣＲ扩增产物强度，Ⅱ级，０．２５±０．０８／ｍｍ２，Ⅱ级，０．５４±０．１２／ｍｍ２ｐ＜０．０５），而两组α３（Ⅳ）ｍＲＮＡ表达，以及肾小球胶原Ⅳ组化染色强度差异无显著意义。提示检测肾小球α２（Ⅳ）ｍＲＮＡ表达可能作为ＩｇＡ肾病病理分级的一项敏感指标，为ＩｇＡ肾病预后判断提供一定帮助。不同病变程度的系膜增殖性肾炎患者肾小球α２（Ⅳ）基因表达无明显差异。可能与二者预后不同有关。

he levels of extracellular matrix protein mRNAswere increased prior to the appearance of histologicalglomerulosclerosis in isolated glomeruli from several ani-mal models. Striker studied renal biopsies (Seminar inNephrology, 13 : 508, 1993). We made a comparablestudy in human renal biopsies to assess the levels ofglomerular α2 (Ⅳ) and α3 (Ⅳ) collagen gene expres-sions in renal biopsies. Renal biopsy specimens were ob-tained from 11 patients (7 IgA nephropathy and 4mesangial proliferative glomerulonephritisi). Glomerularlesion was divided into 5 grades. The amount of colla-gen type Ⅳ in glomerular matrix was evaluated by im-munoperoxidase staining using a monoclonal antibody totype Ⅳ collagen. For gene expression analysis.glomeruli were dissected out from about 10% of eachbiopsy speciman. The expressions of α2 (Ⅳ) and α3(Ⅳ) collagen mRNAs were analyzed by using in situreverse transcription coupled with polymerase chain re-action. Each PCR reaction contained an amount of cD-NA template equivalent to that obtained from 1/10 of aglomerulus. α2 (Ⅳ) and α3(Ⅳ) collagen mRNAs weredetected in all specimens. All 3 cases of IgAN withgrade Ⅲ glomerular lesion had a more marked incre-ment of glomerular α2(Ⅳ) collagen cDNA than that ofthe other 3 IgAN patients with grade Ⅱ lesion (the in-tensity of PCR product, grade Ⅲ 0. 54 ± 0. 12, VSgrade Ⅱ 0. 25 ± 0. 08 , P<0. 05). No discrepancies weredetected in the level of glomerular α3 (Ⅳ) collagen cDNA and the intensity of collagen iV staining betweenthese two groups of IgAN. Interestingly, in MsPGNpatients there was no difference in the expression ofglomerular α2 (Ⅳ) collagen mRNA between grade Ⅱand grade Ⅲ glomerular lesions. The results suggestedthat the detection of glomerular α2 (Ⅳ) collagen mRNAlevel in lgAN patients may help to define the pathologi-cal classification.