The effect of intermittent cryotherapy on the activities of citrate synthase and lactate dehydrogenase in regenerating skeletal muscle

This study examined the effect of three sessions of cryotherapy (three sessions of 30 minutes applied each 2 h) and muscle compression in the regenerating skeletal muscle of the rats. The middle belly of tibialis anterior muscle was injured by a frozen iron bar and received one of the following intervention: injury + cryotherapy (treated with cryotherapy); injury + placebo (sand pack), and injury (I).The enzymatic activities of citrate synthase (CS) and lactate dehydrogenase (LDH) were measured in the presence of 1mM or 10mM pyruvate. The ANOVA and Tukey's test (p<0.05) were performed for the statistical analysis. In summary, the intermittent sessions of cryotherapy, associated to muscle compression and applied immediately after the primary muscle injury minimized the CS and LDH activity at 4h30 and 24h periods post-lesion, which could be related to the reduction in the secondary muscle injury inherent to cryotherapy treatment.

Quantification of reduced glutathione by analyzing glutathine-S-transferase reaction process taking into account of product inhibition / 西安交通大学学报(医学版)

Objective To investigate the reliability of the integrated method for kinetic assay of substrate in the presence of product inhibition using glutathione-S-transferase(GST) as model.Methods Purified GST from pig liver was used to catalyze the conjugation of reduced glutathione(GSH) to 1-chloro-2,4-dinitrobenzene(CDNB)(final concentration at 1.0mmol/L),and reaction curve was monitored by product absorbance at 340nm.Maximal product absorbance after the completion of reaction was predicted by the integrated method.Results The optimization of product inhibition constant conferred to resistance to the variation of residual substrate concentration on the estimation of maximal product absorbance.This integrated method for kinetic substrate assay was also resistant to common source of errors.The recovery for extra GSH in rat liver homogenate was above 98% with linear response ranged from 2.0?mol/L to 90 ?mol/L.The concentration of GSH in rat liver was consistent to previous reports.Conclusion The integrated method is valid for kinetic assay of substrate when there is product inhibition,and it exhibits some universality as a kinetic method for enzymatic analysis with obvious advantages.