## 2 Materials and Methods
### RNA Extraction and Real-Time Polymerase Chain Reaction (PCR)  
To examine the expression of mRNAs associated with muscle protein synthesis and degradation factors in each group, RNA was extracted from the muscle tissue obtained from the rats. Reagents used for RNA extraction were obtained from Sigma-Aldrich. Subsequently, 1 mL of TRIzol and 100 mg of the sample were homogenized, followed by the addition of 200 uL of chloroform and vortexing. The supernatant was recovered by centrifugation, and 500 uL of isopropanol was added to the supernatant. The mixture was then cooled on ice for 10 min to precipitate the RNA. The precipitated RNA pellet was washed, and cDNA was synthesized using the Maxima First Strand cDNA Synthesis Kit for RT-qPCR (Thermo Fisher Scientific, Waltham, MA, USA) in accordance with the manufacturer's instructions. To confirm the expression of mRNA, real-time PCR was performed using TOPrealv(tm) SYBR Green qPCR High-ROX PreMIX, and primers were purchased from Enzymonics (Daejeon, Republic of Korea) and Bione  
\begin{table}
\begin{tabular}{l c c c} \hline \hline  & & **Diet (1)** & \\ \hline
**Composition (g/kg)** & **Control** & **DEX** & **DEX + DMH** \\ \hline Corn starch & 397.486 & 397.486 & 394.596 \\ Maltodextrin & 132 & 132 & 132 \\ Cellulose & 50 & 50 & 50 \\ Sucrose & 100 & 100 & 100 \\ Soybean oil & 70 & 70 & 66.15 \\ Casein & 200 & 200 & 171.74 \\ Mealworm hydrolysate & 0 & 0 & 35 \\ L-cystine & 3 & 3 & 3 \\ Vitamin mix & 10 & 10 & 10 \\ Mineral mix & 35 & 35 & 35 \\choline bitartrate & 2.5 & 2.5 & 2.5 \\ t-Butylhydroquinone & 0.014 & 0.014 & 0.014 \\ \hline Total (g) & 1000 & 1000 & 1000 \\ \hline \hline \end{tabular} (1) DEX, dexamethasone (2.25 mg/kg, i.p.) + control diet; DEX + DMH, dexamethasone (2.25 mg/kg, i.p.) + defatted melworm hydrolysate diet. i.p., intraperitoneal injection.  
\end{table}
Table 1: Composition of control and experimental diet.  
of Korea). The primers utilized in the experiments were \(\beta\)-actin (forward, TAT CCGG CAA TGA GCG GTT CC; reverse, AGC ACT GTG TTG GCA TAG AGG), MuRF-1 (forward, ATC ACT CAG GAG CAG GAG GA; reverse, CTT GGC ACT CAA GAG GAA GG), atrogin-1 (forward, AGC TTG TGC GAT GTT ACC A; reverse, GGT GAA AGT GAG ACG GAG CA), MyoD (forward, ACT ACA GCG GCG ACT CAG AC; reverse, ACT GTA GTG GGC GTC GT), and myogenin (forward, TGA ATG CAA CTC CCA CAG C; reverse, CAG ACA TAT CCT CC ACC GTG). A total of 20 \(\mu\)L was prepared by combining 10 \(\mu\)L of SYBR Green master mix, 1 \(\mu\)L of each forward and reverse primer, 6 \(\mu\)L of DNase-free water, and 2 \(\mu\)L of cDNA. This solution was subjected to real-time PCR using a DTPrime 5 (DNA Technology, Moscow, Russia). The initial denaturation step was set at 95 \({}^{\circ}\)C for 10 min, followed by denaturation at 95 \({}^{\circ}\)C for 10 s, annealing at 60 \({}^{\circ}\)C for 20 s, and extension at 72 \({}^{\circ}\)C for 30 s, repeated for 40 cycles. The relative mRNA expression between each group was determined using the 2\({}^{-\Delta\Delta\text{CI}}\) method, whereby the \(\Delta\)Ct was calculated by subtracting the individual \(\Delta\)Ct values of the experimental group from those of the control group.