Changes in skeletal muscle proteolytic gene expression after prophylactic supplementation of EGCG and NAC and eccentric damage

AbstractPurpose pact of prophylactic supplementation of N-acetyl-cysteine (NAC) and epigallocatechin gallate (EGCG) on intramuscular expression of proteolytic genes after unaccustomed eccentric muscle contractions was investigated. s apparently healthy males (mean ± SD: 20.0 ± 1.8 years, 175 ± 7.1 cm, 76.1 ± 16.9 kg) ingested daily either 1800 mg of NAC or 1800 mg of EGCG (98% total polyphenols, 80% total catechins, and 50% EGCG), or 1000 mg of a glucomannan placebo (PLA) in a double blind, prophylactic fashion for 14 days. Subjects then completed an unaccustomed eccentric exercise bout (100 repetitions at 30° s−1) using the dominant knee extensors. Skeletal muscle biopsies were collected from the vastus lateralis at baseline and both 6 and 24 h after exercise. The expression of proteolytic genes [i.e., muscle ring-finger 1 (MuRF1), atrogin-1, α-type 20S subunit C2 (HC2), α-type 20S subunit C3 (HC3), ubiquitin protein ligase 3B (UBE3B), μ-calpain, and m-calpain] was quantified using real-time RT-PCR. Separate 3 × 3 (group × time) repeated measures ANOVAs were used to analyze changes in gene expression over time between groups. s nificant group × time interactions were detected between groups for the expression of any of the atrogenes or calpains (p > 0.05). Significant main effects for time identified increases in MuRF1 (6 h: 5.3 ± 10.8 fold; p = 0.046), UBE3B (6 h: 5.3 ± 7.7 fold; p = 0.006; 24 h: 3.3 ± 4.5 fold; p = 0.005), and m-calpain expression (6 h: 2.7 ± 4.4 fold; p = 0.045) in all participants following exercise. Increases approached significance in HC2 (6 h: 1.9 ± 2.4 fold; p = 0.079; 24 h: 1.6 ± 1.9 fold; p = 0.084) and m-calpain expression (24 h: 1.8 ± 2.3 fold; p = 0.084) following exercise. sions lactic supplementation of NAC and EGCG did not impact acute changes in skeletal muscle proteolytic gene expression following eccentric exercise. Eccentric muscle contractions elevated MuRF1 and UBE3B, while m-calpain and HC2 mRNA tended to increase.