Curcuma longa L. Water Extract Improves Dexamethasone-Induced Sarcopenia by Modulating the Muscle-Related Gene and Oxidative Stress in Mice

Abstract

Dexamethasone (DEX) promotes proteolysis, which causes muscle atrophy. Muscle atrophy is connected to sarcopenia. We evaluated the effect of Curcuma longa L. water extract (CLW) on DEX-induced muscle atrophy. ICR mice were divided into three groups (eight mice per group) to investigate the capability of CLW in inhibiting muscle atrophy. The control group (Ex-CON) was administered distilled water (DW) by gavage and subjected to exercise; the muscle atrophy group (Ex-DEX) was administered DW by gavage, an injection of DEX (1 mg/kg body weight/day) intraperitoneally (IP), and subjected to exercise; and the treatment group (Ex-CLW) was administered CLW (1 g/kg body weight/day) by gavage, DEX IP injection, and subjected to exercise. Following the injection of DEX, the expression levels of myostatin, MuRF-1, and Atrogin-1 were increased. However, these expression levels were decreased in the Ex-CLW group, thereby leading to the conclusion that CLW inhibits muscle atrophy. ROS (that was overproduced by DEX) decreased antioxidant enzyme activity and increased malondialdehyde (MDA) levels, which led to muscle atrophy. When CLW was ingested, the antioxidant enzyme activities increased while the MDA levels decreased. These findings suggest that CLW could serve as a natural product for the prevention of muscle atrophy by modulating muscle atrophy-related genes and increasing antioxidant potential.

Keywords: Curcuma longa L.; antioxidants; ladder climbing exercise; muscle function; sarcopenia.

Figure 1

Effect of CLW on the body weight and grip strength in mice with DEX-induced muscle atrophy. Ex-CON, DW administration by gavage and saline IP injection group; Ex-DEX, DW administration by gavage and DEX (1 mg/body weight/day) IP injection group; Ex-CLW, CLW administration by gavage (1 g/body weight/day) and DEX IP injection group. (A) Body of the DEX-induced muscle after CLW supplementation in each mouse and (B) grip strength/body weight. Data are expressed as mean ± SE for eight mice in each group. Values with different superscripts indicate a significant difference among groups based on Duncan’s multiple range test (p < 0.05). CLW may help prevent the decrease in grip strength due to muscle atrophy.

Figure 2

Effect of CLW on DEX-induced muscle atrophy. Ex-CON, DW-supplementation and saline IP injection group; Ex-DEX, DW-supplementation and DEX (1 mg/body weight/day) IP injection group; Ex-CLW, CLW supplementation (1 g/body weight/day) and DEX IP injection group. (A) Relative weight of the DEX-induced muscle after CLW supplementation in each mouse. (B) Representative hematoxylin and eosin-stained section of the gastrocnemius muscle. Images were analyzed by microscopy and the cross-sectional area (CSA) was measured (×200). (C) Distribution of the muscle fiber CSA. (D) Cross-sectional area mean. Data are expressed as mean ± SE for eight mice in each group. Values with different superscripts indicate a significant difference among groups based on Duncan’s multiple range test (p < 0.05).

Figure 3

Effect of CLW on the mRNA expression level of the muscle atrophy gene. RT-PCR analysis of the muscle atrophy genes, myostatin, MuRF-1, and Atrogin-1 in the gastrocnemius muscle. Ex-CON, DW supplementation, and saline IP injection group; Ex-DEX, DW-supplementation and DEX (1 mg/body weight/day) IP injection group; Ex-CLW, CLW supplementation (1 g/body weight/day), and DEX IP injection group. Data are expressed as mean ± SE for eight mice in each group. Values with different superscripts indicate a significant difference among groups based on Duncan’s multiple range test (p < 0.05).

Figure 4

Effect of CLW on MuRF-1 and Atrogin-1 in mice with DEX-induced muscle atrophy. (A) MuRF-1 and Atrogin-1 were analyzed by Western blotting. (B,C) Relative density was calculated as the ratio of MuRF-1 and Atrogin-1 expression to β-actin expression. Ex-CON, DW supplementation, and saline IP injection group; Ex-DEX, DW supplementation, and DEX (1 mg/body weight/day) IP injection group; Ex-CLW, CLW supplementation (1 g/body weight/day), and DEX IP injection group. Data are expressed as mean ± SE for eight mice in each group. Values with different superscripts indicate a significant difference among groups based on Duncan’s multiple range test (p < 0.05).

Figure 5

Graphical illustration of how Curcuma longa L. water extract improves dexamethasone-induced sarcopenia by modulating the muscle-related gene and oxidative stress in mice.