ABSTRACT
<p><b>OBJECTIVE</b>To investigate the relationship between heroin spongiform leucoencephalopathy and respiratory chain complex I deficiency.</p><p><b>METHODS</b>The activity of respiratory chain complex I in peripheral white blood cell mitochondria was compared between 36 cases of heroin spongiform leucoencephalopathy and 36 healthy subjects using enzyme-linked immunosorbent assay (ELISA).</p><p><b>RESULTS</b>The activity of respiratory chain complex I was 5.6∓2.4 U/ml in patients with heroin spongiform leucoencephalopathy, significantly higher than that in the normal subjects (4.2∓2.1 U/ml, t=2.634, P<0.05).</p><p><b>CONCLUSION</b>In patients with heroin spongiform leucoencephalopathy, mitochondrial dysfunction results in energy metabolism disorder to cause extensive demyelination of the cerebral white matter. Respiratory chain complex I deficiency of the mitochondria plays a significant role in the pathogenesis of heroin spongiform leucoencephalopathy.</p>