Objective To observe the effects of mesenchymal stem cells (BMSCs) on the expression of Bcl2 and Bax in atrophied muscles.Methods Immature rats (80～ 100 g) were anesthetized to collect marrow from their femurs and tibias.BMSCs were isolated from the marrow,cultured and purified using the whole bone marrow adherence method.Their right hindlimbs were immobilized fiom the thigh to the paw with the knee in extension and the ankle in plantar flexion.After the modeling,24 of the male rats were divided into a sham-operation group,a BMSC group and a phosphate buffer solution (PBS) group,each of 8.The BMSC and PBS groups were injected with either approximately 106 BMSCs or an equal volume of PBS into the belly of the soleus muscle after they had been immobilized for 48 hours,while the control group did not undergo any treatment except for the injection of PBS.All of the rats were sacrificed for analysis after 14 days.Results The BMSCs were mainly spindle cells,showing radial colony arrangement.They grew vigorously and could passage in a continuous and stable manner over 10 passages.At the 4th passage the BMSCs were positive for CD44 (95.84％) and CD90 (96.00％),but negative for CD34 and CD45.Western blotting assay demonstrated that the expression of Bax protein as measured in grey-scale value (0.41±0.08)in the BMSC group was significantly lower than in the PBS group (0.63±0.10),but significantly higher than in the control group (0.14±0.11) on average.The expression of Bcl-2 (0.47±0.14) was also significantly higher in the BMSC group than in the PBS group (0.22-± 0.13),but significantly lower than in the control group (0.81 ± 0.06).Conclusion Bone marrow mesenchymal stem cells can upregulate the expression of anti-apoptotic Bcl-2 protein and downregulate that of the apoptotic Bax protein when injected early into the belly of a muscle in an immobilized limb.

Objective To observe the effects of treadmill training at different intensities on the expression of p-AKT in rats' gastrocnemius muscles after focal cerebral ischemia,and to investigate whether intensive training is beneficial for the recovery of motor function.Methods Left middle cerebral artery occlusion (MCAO) was induced in 120 male Wistar rats using the intraluminal thread method,and they were divided into an MCAO group (no training),a normal training group (treadmill training once a day for 30 min) and an intensive training group (treadmill training twice a day for 60 min),each of 30 rats.There was also a sham control group with 30 members not given MCAO or training.The four groups were further divided into 3 day,7 day and 14 day subgroups.Five rats randomly selected from each subgroup were sacrificed for hematoxylin-eosin staining after 4％ paraformaldehyde treatment.Neurological function was evaluated using Zausinger scores,and the expression of p-Akt was detected by western blotting.Results No significant differences in Zausinger scores were observed between the intensive training group and the normal training group after 1,3 or 7 days of training.However the average Zausinger score in the intensive training group was significantly higher than in the normal training group after 14 d of treadmill training.After 7 d and 14 d of treadmill training the average cross-sectional area of the gastrocnemius muscles in the sham group was significantly higher than in the other three groups.The average area of the intensive training group was significantly larger than that of the normal training group.The expression of p-Akt in the gastrocnemius was significantly increased in the intensive training group compared with the normal training group in the 7 day and 14 day subgroups.Conclusion Treadmill training can improve the expression of p-Akt in atrophied gastrocnemius muscles caused by MCAO.Intensive training is more effective for the recovery of muscle function.

The development of broad-spectrum antivirals against human coronaviruses (HCoVs) is critical to combat the current coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its variants, as well as future outbreaks of emerging CoVs. We have previously identified a polyethylene glycol-conjugated (PEGylated) lipopeptide, EK1C4, with potent pan-CoV fusion inhibitory activity. However, PEG linkers in peptide or protein drugs may reduce stability or induce anti-PEG antibodies in vivo. Therefore, we herein report the design and synthesis of a series of dePEGylated lipopeptide-based pan-CoV fusion inhibitors featuring the replacement of the PEG linker with amino acids in the heptad repeat 2 C-terminal fragment (HR2-CF) of HCoV-OC43. Among these lipopeptides, EKL1C showed the most potent inhibitory activity against infection by SARS-CoV-2 and its spike (S) mutants, as well as other HCoVs and some bat SARS-related coronaviruses (SARSr-CoVs) tested. The dePEGylated lipopeptide EKL1C exhibited significantly stronger resistance to proteolytic enzymes, better metabolic stability in mouse serum, higher thermostability than the PEGylated lipopeptide EK1C4, suggesting that EKL1C could be further developed as a candidate prophylactic and therapeutic for COVID-19 and other coronavirus diseases.