Second harmonic generation microscopy of pse-like zones from pork semimembranosus

The aim of this work was to study the sarcomeric organization of muscles with PSE-like zones and normal muscle (control), focusing on the SHG signal pattern of myosin (single or double band). Second harmonic generation microscopy has been applied on pork Semimembranosus samples fixed at 24 hours post mortem. Electronic microscopy was applied on the same samples to improve SHG images interpretation. PSE-like zones were presenting SHG signal with a higher single band frequency than the control muscles (87.5% vs 35%, respectively). The defect SHG pattern was close to the data obtained on skeletal muscle in normal physiological conditions. This result indicates that the sarcomeric alignment is mostly maintained in PSE-like zone whereas the alignment is over in normal muscle. Electronic microscopy images confirmed this data. This study reveals that SHG microscopy could be a new tool to identify structure defects in pork muscles at 24h postmortem, in addition to the subjective PSE-like zone scale.