Changes in apoptosis factors and activation of caspase-3 in tilapia muscle during storage

Yan-Fu He,Hui Huang,Lai-Hao Li,Xian-Qing Yang,Shu-Xian Hao,Yong-Qiang Zhao

doi:10.1080/10942912.2018.1494199

Abstract

ABSTRACTThe activation of the apoptosis pathway in tilapia muscle during postmortem storage was studied. Changes in caspase-3 activity, ATP content, cytochrome c levels, and ratio of Bcl-2/Bax levels of tilapia muscle were observed during postmortem storage at 20°C. Caspase-3 activity was found to be significantly increased at first, followed by a decrease (P < 0.05); the highest caspase-3 activity was observed at 1 h. The ATP content decreased significantly (P < 0.05), and almost exhausted after 10 h storage. The cytochrome c level in the cytosol showed a significant increase after 5 h of storage (P < 0.05), while the mitochondrial cytochrome c levels showed a decrease. The Bcl-2/Bax ratio was stable from 0–5 h, followed by a rapid decreased at 10–20 h and a significant increased after 20 h (P < 0.05), suggesting that the apoptosis process occurred until 20 h of postmortem storage. Thus, we concluded that the availability of ATP and the increase in cytosolic cytochrome c levels are essential for the activation of caspase-3, and that the former partly limits caspase-3 activity.

Highlights

Meat quality during postmortem storage is attributed to the degradation of certain major myofibrillar proteins[1], which are responsible for maintaining the integrity of the myofibrillar structure.[2,3]
The present results indicated that both Bcl-2 and Bax play important roles in the apoptosis process in muscles during postmortem storage
We investigated the activation of the apoptosis pathway and its potential influencing factors in tilapia muscle during postmortem storage in an attempt to explore the mechanisms of apoptotic pathways and their regulation

Summary

Introduction

Meat quality during postmortem storage is attributed to the degradation of certain major myofibrillar proteins[1], which are responsible for maintaining the integrity of the myofibrillar structure.[2,3] Previous studies have reported that endogenous enzymes in the skeletal muscles, such as calpains, proteasomes, lysosomal cathepsins, and caspases, are responsible for the degradation of myofibrillar proteins.[4,5,6] Calpains are the most important of these proteins, and have been performed to many in-depth studies. The calpains system cannot completely explain the degradation of major cytoskeleton proteins during the whole postmortem storage. Myofibrils were found to be cleaved in the presence of calpain inhibitors.[7] In addition, the presence or absence of the calpains seems to have no effects on the degradation of some cytoskeletal proteins during postmortem storage. A recent study suggested that caspases are associated with changes in meat quality during postmortem storage, and their effects cannot be ignored.[8]

Methods

Results

Conclusion