[Changes of perimysial junctional plates induced by excessive eccentric training and the effects of acupuncture intervention].

This study aimed to investigate the effects of acupuncture intervention on excessive eccentric training-induced changes of perimysial junctional plates (PJPs) domain. Thirty healthy male Wistar rats were randomly assigned to 5 groups: control group, four-week training group, four-week training + 1-week recovery group and four-week training + 1-week acupuncture group. Rats were subjected to continuous excessive eccentric training for 4 weeks (incline -16°, speed 16-20 m/min, 60-90 min/d, 5 day per week), and then were subjected to one-week spontaneous recovery or one-week recovery with acupuncture intervention (a piece of filiform needle for 4 min every day). The PJPs domain changes were observed under transmission electron microscopy, and the perimysial collagen network structural changes were examined by scanning electron microscopy with or without a digestion technique (NaOH). The following results were obtained: (1) Compared with control group, PJPs domain of four-week training group showed excessive shortening of sarcomere (P < 0.001), serious damage of sarcomere structure, and altered mitochondria morphology in intermyofibria and subsarcolemma; 54% degradation of sarcolemma, and increased number of caveolae (P < 0.01); reduced number of PJPs (P < 0.001). (2) In comparison with four-week training group, PJPs domain was slightly changed in four-week training + 1-week recovery group, i.e., partial recovery of sarcomere length and structure (accounting for 85.23% of control group), and recovery of intermyofibrial and subsarcolemmal mitochondria morphology; decreased sarcolemmal degradation (P < 0.001), and increased number of caveolae (P < 0.05); increased PJPs number (P < 0.001). (3) PJPs domain changed in four-week training + 1-week acupuncture group compared with four-week training + 1-week recovery group, which were substantial recovery of sarcomere length (accounting for 94.51% of control group), increased subsarcolemmal mitochondrial fusion (P < 0.001), decreased caveolae number (P < 0.001), and decreased PJPs number (P < 0.001). The results indicated that excessive eccentric training resulted in excessively reduced number of PJPs with altered PJPs domain homeostasis, thus impeding the adaptability to eccentric training. After 1 week of natural recovery, the number of PJPs was excessively increased, hindering muscle damage repair. Acupuncture intervention helped to recover PJPs number and PJPs domain homeostasis, thus significantly relieving overuse injuries.

Preparation of cell-embedded colloidosomes in an oil-in-water emulsion.

Cell encapsulation by locking the interfacial microgels in a water-in-oil Pickering emulsion has currently been attracting intensive attention because of the biofriendly reaction condition. Various kinds of functional microgels can only stabilize an oil-in-water Pickering emulsion, and it is thus difficult to encapsulate cells in the emulsion where the cells are usually dispersed in the continuous phase. Herein, we introduce a facile method for preparing cell-embedded colloidosomes in an oil-in-water emulsion via polyelectrolyte complexation. Escherichia coli (E. coli) was chosen as a model cell and embedded in the thin shell of chitosan/poly(N-isopropylacrylamide-co-acrylic acid) (P(NIPAM-co-AAc)) microcapsules. This is beneficial for expressing cell function because of the little resistance of mass exchange between the embedded cells and the external environment. Cells can be used in biocatalysis or biomedicine and our product will hold great promises to improve the performance in those fields. The synthesis route presents a platform to prepare cell-embedded microcapsules in an oil-in-water Pickering emulsion in a facile and biocompatible way. First, an emulsion stabilized by P(NIPAM-co-AAc) microgels was prepared. Then, the interfacial microgels in the emulsion were locked by chitosan to form colloidosomes. The mechanism of cell encapsulation in this system was studied via fluorescent labeling. The viability of E. coli after encapsulation is ca. 90%. Encapsulated E. coli is able to metabolize glucose from solution, and exhibits a slower rate than free E. coli. This demonstrates a diffusion constraint through the colloidosome shell.