Disorder of endoplasmic reticulum calcium channel components is associated with the increased apoptotic potential in pale, soft, exudative pork

Eight pale, soft and exudative (PSE) and eight reddish-pink, firm and non-exudative (RFN) porcine longissimus muscle samples were selected based on pH and L* at 1h postmortem (PM), and drip loss at 24h PM, and used to evaluate the cellular calcium and apoptosis status. We found that SERCA1 was decreased, while IP3R was decreased in PSE meat (P<0.05), indicative of the overloaded sarcoplasmic calcium status. In PSE meat, the pro-apoptotic factor BAX was increased while the anti-apoptotic factor Bcl-2 was decreased (P<0.05). The significantly increased activity of caspase 3 and the expression of its cleavage fragment suggested higher apoptotic potential in PSE meat compared with RFN meat (P<0.05). Moreover, the significantly higher expression level of cytochrome C (P<0.05) suggests the important role of mitochondria during apoptosis appearance in PSE meat. Taken together, our data inferred that the calcium channel disorder present in PSE meat was associated with the increased apoptotic potential.