Isolation, identification, and induced differentiation of satellite cells from skeletal muscle of adult tree shrews.

A method for the in vitro isolation, purification, identification, and induced differentiation of satellite cells from adult tree shrew skeletal muscle was established. The mixed enzyme digestion method and differential adhesion method were used to obtain skeletal muscle satellite cells, which were identified and induced to differentiate to verify their pluripotency. The use of a mixture of collagenase II, hyaluronidase IV, and DNase I is an efficient method for isolating adult tree shrew skeletal muscle satellite cells. The P3 generation of cells had good morphology, rapid proliferation, high viability, and an "S"-shaped growth curve. Reverse transcription-polymerase chain reaction (RT-PCR) and immunofluorescence staining indicated that marker genes or proteins were expressed in skeletal muscle satellite cells. After myogenic differentiation was induced, multiple-nucleated myotubes were observed, and the MyHC protein was expressed. The expression of myogenic marker genes changed with the differentiation process. After the induction of adipogenic differentiation, orange-red lipid droplets were observed, and the expression of adipogenic marker genes increased gradually with the differentiation process. In summary, satellite cells from adult tree shrew skeletal muscle were successfully isolated using a mixed enzyme digestion method, and their potential for differentiation into myogenic and adipogenic cells was confirmed, laying a foundation for further in vitro study of tree shrew muscle damage.

The regulation of expression and splicing of transcription factors are related to the muscle damage caused by radiation in tree shrews.

Radiotherapy-induced muscle injury (RIMI) is a major complication of radiotherapy for nasopharyngeal carcinoma. Transcription factor (TF) expression and alternative splicing are crucial events in transcriptional and posttranscriptional regulation, respectively, and are known to be involved in key signaling pathways contributing to a variety of human disorders, including radiation injury. To investigate the TFs and alternative splicing events involved in RIMI, we constructed a tree shrew model as described previously in which the RIMI group received 20 Gy of irradiation on the tensor veli palatini (TVP) muscles. The irradiated muscles were evaluated by RNA sequencing (RNA-seq) 6 months later, and the results compared with those for normal TVP muscles. The alt5p and alt3p events were the two main types of differentially regulated alternative splicing events (RASEs) identified via the Splice sites Usage Variation Analysis (SUVA) software, and these RASEs were highly conserved in RIMI. According to functional enrichment analysis, the differentially RASEs were primarily enriched in pathways related to transcriptional regulation. Furthermore, we identified 16 alternative splicing TFs (ASTFs) in ASTF-differentially expressed gene (DEG) networks based on co-expression analysis, and the regulatory networks were chiefly enriched in pathways linked to cell proliferation and differentiation. This study revealed that RASEs and ASTF-DEG networks may both play important regulatory roles in gene expression network alteration in RIMI. Future studies on the targeting mechanisms and early interventions directed at RASEs and ASTF-DEG networks may aid in the treatment of RIMI.

Simple method for generating special beams using polarization holography.

Vector vortex beams are a kind of special beam that simultaneously carry spin and orbital angular momentum. The generation of vector vortex beams usually requires a complex and expensive optical system, which becomes a bottleneck hindering its further application. Thus, a compact, low-cost and efficient special beam generation system is demanded. In this paper, a method that can produce vector vortex beams distributed anywhere in the equator of hybrid-order Poincaré Spheres based on polarization holography is proposed. Via changing some parameters of the device, this method can also produce the scalar vortex beams distributed at any position of the basic Poincaré Sphere and the vector beams distributed at the equator of the higher-order Poincaré Spheres. The work shows that polarization holography has the potential ability to regulate the spin and orbital angular momentum simultaneously, opening a new window for future research and applications of angular momentum space orientation.

An Investigation of the Mechanisms of Radiation-Induced Muscle Injury in a Tree Shrew (Tupaia belangeri) Model.

Background: Animal models suitable for investigating mechanisms behind radiation-induced muscle injury are lacking. We developed a tree shrew model of such injury and investigated pathological changes and mechanisms. Methods: Animals were divided into control (n = 5), radiation-induced acute injury (n = 5), and radiation-induced chronic injury (n = 5) groups. Tensor veli palatini (TVP) muscles of acute injury and chronic injury groups were dissected under a microscope at 1 and 24 weeks after radiation therapy, respectively. TVP muscles were stained with HE and Masson to visualize pathological changes. ELISA was performed to measure oxidative injury. RT-qPCR and immunohistochemical staining was performed to measure expression levels of miR-206 and histone deacetylase 4 (HDAC4). Results: Compared to the control group, acute injury group showed a significant decrease in miR-206 expression (.061 ± .38, P < .05) and a significant increase in HDAC4 expression (37.05 ± 20.68, P < .05). Chronic injury group showed a significant decrease in miR-206 expression (.23 ± .19, P < .05) and a significant increase in HDAC4 expression (9.66 ± 6.12, P < .05). Discussion: A tree shrew model of radiation-induced muscle injury was established by exposing TVP muscle region to radiation of 20-Gy. Experimental results indicated that injury caused by radiation persisted despite gradual healing of the TVP muscle and miR-206 regulatory pathway plays a key role in regulating radiation-induced muscle injury.