程序化细胞死亡分子5及其他凋亡调控蛋白在线粒体病患者骨骼肌中的表达

目的 检测程序化细胞死亡分子5(PDCD5)、半胱氨酸蛋白水解酶(Caspase-3)、Bax和Bcl-2蛋白在线粒体脑肌病伴随乳酸血症和卒中样发作(MELAS)、肢带型线粒体肌病(LGMM)及慢性进行性眼外肌瘫痪(CPEO)患者骨骼肌中的表达情况,探讨细胞凋亡与线粒体病发病机制之间的关系.方法 选择经临床、病理及基因检查诊断的3例MELAS、2例LGMM和6例CPEO患者,对骨骼肌进行PDCD5、Caspase-3、Bcl-2和Bax蛋白免疫组织化学染色,以11例非骨骼肌疾病患者的肌肉标本进行对照.结果 PDCD5和Caspase-3在个别破碎红纤维(RRF)膜下和少数毛细血管高表达,在对照无表达;Bcl-2在病例组和对照组的许多小血管中表达,在病例组的许多RRF和毛细血管表达增强;Bax在正常对照和患者组的肌纤维和毛细血管未见表达.结论 线粒体病患者的骨骼肌内存在细胞凋亡过程的异常调节,PDCD5、Caspase-3、Bcl-2和Bax参与其中.

Expressions of PDCD5 and other apoptosis-related proteins in muscle of patients with mitochondrial cytopathy

Objective To investigate the expression of PDCDS, Caspase-3, Bcl-2 and Bax in skeletal muscle of patients with mitochondrial encephalomyopathies with lactate acidosis and stroke like episodes (MELAS), limb-girdle type mitochondrial myopathy (LGMM) and chronic progressive external ophthalmoplegia (CPEO), and to explore the correlation between apoptosis and the pathogenesis of mitochondrial cytopathy. Methods Three patients with MELAS, 2 patients with LGMM and 6 patients with CPEO were enrolled, including eight males and three females, the diagnosis of MELAS, LGMM or CPEO was made on the basis of clinical manifestations, muscle biopsy specimen findings and a point mutation or a large-scale mitochondrial DNA deletion. Controls consisted of 11 muscle biopsy samples from subjects with no diagnostic findings (age and gender matched with patients'). Muscle biopsy was performed after obtaining the informed consent. The specimens were quickly frozen and transverse sections stained for hematoxylin-eosin, periodic acid Schiff reaction, oil red "O", modified Gomori trichrome, ATPase, NADH-TR, succinate dehydrogenase, cytochrome c oxidase, and nonspecific esterase. The expression of PDCD5, Caspase-3, Bcl-2 and Bax were detected by immunohistechemistry. The authors used the tissue slices of prostate or tonsil containing the target protein as positive control and PBS in place of these primary antibodies as negative control. Results PDCD5 was highly expressed in some ragged red fibers in 2 patients with LGMM and 3 patients with CPEO. And it was also expressed in some capillary of patients with MELAS and LGMM. Caspase-3 was expressed in a few ragged red fibers in 1 patients with MELAS, 2 patients with LGMM and 1 patient with CPEO. And there was also expression in some capillary of both MELAS and LGMM. Bcl-2 staining showed a high expression in sarcoplasm of some ragged red fibers and atrophic fibers in 4 patients with MELAS, 2 patients with LGMM and 5 patients with CPEO, at the same time, it was weakly expressed in sarcoplasm of all type 2 muscle fibers and some small vessels of both patients and controls. There was no Bax immunoreactive fiber or vessel in MELAS, LGMM and CPEO patients. All of the abone-mentioned proteins except Bcl-2 were negative in muscle fibers and vessels of controls. Conclusion Abnormal regulation of apoptosis is involved in the pathophysiology of mitochondrial cytopathy. And PDCD5, Bcl-2 and Caspase-3 take part in regulation.