Prayson R A, Yu A C
Department of Anatomic Pathology, Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA.
Arch Pathol Lab Med. 2001 Oct;125(10):1326-30. doi: 10.5858/2001-125-1326-BBXABE.
Bcl-2, Bcl-x, and Bax are among the variety of proteins that have been described as being involved in the regulation of apoptotic cell death. Bcl-2 and Bcl-x(L) inhibit apoptosis, and Bax is proapoptotic.
To evaluate the expression of Bcl-2, Bcl-x, and Bax in inclusion body myositis (IBM).Design.-We examined muscle specimens from 27 patients (17 men, 10 women) with IBM to evaluate Bcl-2, Bcl-x, and Bax expression by immunohistochemistry.
Patient ages ranged from 29 to 80 years (mean 62.2 years). All biopsies were marked by endomysial chronic inflammation, muscle fiber necrosis, and regeneration. Rimmed (autophagic) vacuoles were present in all cases. Ragged red fibers were noted in 4 biopsies (15%), and cytochrome oxidase-deficient fibers were found in 10 biopsies (37%). Ultrastructural evidence of intranuclear or cytoplasmic tubulofilamentous inclusions, confirming the diagnosis of IBM, were noted in all cases. Paracrystalline mitochondrial inclusions were seen in 5 biopsies (18.5%). Inflammatory cells stained positively with Bcl-2 in all biopsies, Bax in 26 biopsies (96%), and Bcl-x in 8 biopsies (30%). Degenerating muscle fibers were highlighted with Bax in 24 biopsies (89%), Bcl-2 in 2 biopsies (7%), and Bcl-x in 3 biopsies (11%). Regenerative muscle fibers were noted to stain with Bax in 24 muscles (89%), Bcl-2 in 21 muscles (78%), and Bcl-x in 4 muscles (15%). Rimmed vacuoles were highlighted by Bax in 24 biopsies (89%) and only rarely by Bcl-2 (n = 2, 7%) and Bcl-x (n = 3, 11%). A subsarcolemmal staining pattern was observed in 21 biopsies (78%) with Bax, 6 biopsies (22%) with Bcl-2, and only 1 biopsy (4%) with Bcl-x.
(1) Bax (proapoptotic) immunostaining highlighted most autophagic vacuoles; (2) subsarcolemmal Bax and Bcl-2 immunoreactivity may be associated with mitochondrial defects that are commonly noted in IBM; (3) Bcl-2 and Bax immunoreactivity were not confined to degenerating muscle fibers and in fact appeared to be expressed more commonly in regenerating fibers, suggesting that their expression may be independent of apoptosis in the setting of IBM.
Bcl-2、Bcl-x和Bax是多种被描述为参与凋亡性细胞死亡调节的蛋白质。Bcl-2和Bcl-x(L)抑制细胞凋亡，而Bax具有促凋亡作用。
评估Bcl-2、Bcl-x和Bax在包涵体肌炎（IBM）中的表达。
我们检查了27例IBM患者（17例男性，10例女性）的肌肉标本，通过免疫组织化学评估Bcl-2、Bcl-x和Bax的表达。
患者年龄在29至80岁之间（平均62.2岁）。所有活检标本均有肌内膜慢性炎症、肌纤维坏死和再生。所有病例均存在镶边（自噬性）空泡。4例活检标本（15%）可见破碎红纤维，10例活检标本（37%）发现细胞色素氧化酶缺陷纤维。所有病例均有核内或胞质内管状细丝包涵体的超微结构证据，确诊为IBM。5例活检标本（18.5%）可见副结晶样线粒体包涵体。在所有活检标本中炎症细胞Bcl-2染色均呈阳性，26例（96%）Bax染色呈阳性，8例（30%）Bcl-x染色呈阳性。24例活检标本（89%）中退变肌纤维Bax染色明显，2例（7%）Bcl-2染色明显，3例（11%）Bcl-x染色明显。24块肌肉（89%）中再生肌纤维Bax染色呈阳性，21块肌肉（78%）Bcl-2染色呈阳性，4块肌肉（15%）Bcl-x染色呈阳性。24例活检标本（89%）中镶边空泡Bax染色明显，仅2例（7%）Bcl-2染色明显，3例（11%）Bcl-x染色明显。21例活检标本（78%）中Bax呈肌膜下染色模式，6例（22%）Bcl-2呈肌膜下染色模式，仅1例（4%）Bcl-x呈肌膜下染色模式。
（1）Bax（促凋亡）免疫染色突出显示了大多数自噬空泡；（2）肌膜下Bax和Bcl-2免疫反应性可能与IBM中常见的线粒体缺陷有关；（3）Bcl-2和Bax免疫反应性不仅局限于退变肌纤维，实际上在再生纤维中表达更为常见，这表明它们的表达在IBM背景下可能与细胞凋亡无关。
