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. 2021 Feb 25;18(1):28-33.
doi: 10.4274/tjps.galenos.2019.53323.

Masticatory Functional Load Increases the mRNA Expression Levels of ACTN2 and ACTN3 and the Protein Expression of α-Actinin-2 in Rat Masseter Muscle

Nur Masita Silviana  1 , Sri Andarini  2 , Diana Lyrawati  3 , Mohammad Hidayat  4
Affiliations

Masticatory Functional Load Increases the mRNA Expression Levels of ACTN2 and ACTN3 and the Protein Expression of α-Actinin-2 in Rat Masseter Muscle

Nur Masita Silviana et al. Turk J Pharm Sci. .

Abstract

Objectives: α-actinins play structural and regulatory roles in cytoskeletal organization. They form a lattice structure that secures actin in thin filaments, which generate and transmit muscle contractile forces. The morphological and biochemical characteristics of rat masseter muscles are known to change reactions to masticatory functional loads, but their effect on α-actinins remains unknown. This study aimed to determine the response of α-actinins to masticatory functional loads.

Materials and methods: Twenty-four male Wistar rats aged 3 weeks were divided randomly into 3 groups of liquid diet (LD), soft diet, and hard diet (HD). The rats were then sacrificed at the end of 8 weeks. The middle part of superficial masseter muscles was examined to investigate the masticatory effect of functional load on the mRNA expression levels of ACTN2 and ACTN3 and the protein expression levels of α-actinin-2 and α-actinin-3.

Results: The mRNA expression levels of ACTN2 and ACTN3 and the protein expression levels of α-actinin-2 of the HD group were significantly higher than those of the LD group, which served as the control group.

Conclusion: Masticatory functional load organizes the mRNA expression levels of ACTN2 and ACTN3 and the protein expression levels of α-actinin-2 in rat masseter muscles through stimuli during muscle physiological adaptation.

Keywords: masseter muscles; masticatory function; α-actinins.

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Conflict of interest statement

Conflicts of interest: No conflict of interest was declared by the authors. The authors alone are responsible for the content and writing of the paper.

Figures

Figure 1
Figure 1
mRNA expression levels of ACTN2 and ACTN3 in masseter muscles shown as fold change compared with those in the liquid diet group as the control group. Statistical analysis was performed via One-Way ANOVA with Tukey’s post-hoc test. *Significant with p<0.05. LD: Liquid diet SD: Soft diet HD: Hard diet
Figure 2
Figure 2
Western blot analysis. A) α-actinin-2 and B) α-actinin-3 protein expression in the LD, SD, and HD groups. β-actin was used as the sample loading control. The bar graphs on the right represent means ± SEM. *Significant with p<0.05. LD: Liquid diet SD: Soft diet HD: Hard diet, SEM: Standard error of the mean
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