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Effect of arachidonic acid cytochrome P450ω hydroxylase Cyp4a14 gene knockout on skeletal muscle regeneration after injury

ZHANG Cong-Cong, HAN Ying-Chun, CHENG Nai-Xuan, DU Jie^*

Vascular Biology Department of Beijing Anzhen Hospital, Capital Medical University, Beijing Institute of Heart, Lung and Vascular Diseases, Beijing 100029, China

Abstract

The objective of this study was to explore the roles of arachidonic acid cytochrome P450ω hydroxylase CYP4A14 in skeletal muscle regeneration after injury. Wild-type (WT) control mice and Cyp4a14 knockout (A14−/−) mice were used to establish the muscle injury and regeneration model by intramuscular injection with cardiotoxin (CTX) on the tibial anterior (TA) muscle. The TA muscles were harvested at the time points of 0, 3, 5 and 15 days after injury. The changes in skeletal muscle regeneration and fibrosis were assessed by wheat germ agglutinin (WGA) staining and Sirius Red staining. Immunohistochemical staining was used to observe the expression of proliferation-related protein Ki-67 and macrophage marker protein Mac-2. The mRNA levels of regeneration and inflammation associated genes were analyzed by real-time PCR. The results showed that the cross-section area (CSA) of regenerated myofibers in A14−/− mice was significantly smaller (P < 0.05), while the percentage of fibrosis area was significantly higher than those in WT mice at 15 days after injury (P < 0.05). In A14−/− muscles, both the ratio of Ki-67 positive proliferating cells and the mRNA levels of differentiation associated genes Myod1 and Myog were significantly lower than those in WT muscles (P < 0.05). At 3 days after injury, the mRNA expression of inflammatory cells marker genes CD45 and CD11b and Mac-2 positive macrophages in A14−/− muscles were significantly lower than those in WT skeletal muscle (P < 0.05). Macrophages derived pro-regeneration cytokines IL-1β, IGF-1 and SDF-1 were also significantly decreased in A14−/− muscles (P < 0.05). These results suggest that arachidonic acid cytochrome P450ω hydroxylase CYP4A14 plays a critical role in skeletal muscle regeneration after injury.

Key words: skeletal muscle regeneration; arachidonic acid; cytochrome P450ω hydroxylase; myoblast; inflammation

Received: 2020-12-08　　Accepted: 2021-03-11

Corresponding author: 杜杰　　E-mail: jiedu@ccmu.edu.cn

DOI: 10.13294/j.aps.2021.0049

Citing This Article：

ZHANG Cong-Cong, HAN Ying-Chun, CHENG Nai-Xuan, DU Jie. Effect of arachidonic acid cytochrome P450ω hydroxylase Cyp4a14 gene knockout on skeletal muscle regeneration after injury. Acta Physiol Sin 2021; 73 (4): 577-583 (in Chinese with English abstract).