Fig. 3. Erythropoietin protects mitochondrial morphology. Mitochondria were divided into two different populations: subsarcolemmal mitochondria (SSM, the two first columns) and interfibrillar mitochondria (IFM, the two others columns). Mitochondrial morphology was observed using transmission electron microscopy. SSM and IFM of the SS group ( A – B and C – D , respectively) were normal. Abnormal mitochondrial morphology induced by bupivacaine was seen in SSM ( E – F and I – J ), in addition to IFM with onion-like structures ( G – H ) and membrane structures presumed to be autophagosomes ( K – L ). Recombinant human erythropoietin pretreatment partially prevented these anomalies in SSM ( M – N ) and in IFM ( O – P ). ap = autophagosome; ols = onion-like structure. Scale bar , 500 nm.