Effect of repeated eccentric exercise on muscle damage markers and motor unit control strategies in arm and hand muscle

To examine the contralateral repeated bout effect (CL-RBE) on muscle damage markers and motor unit (MU) control strategies, seventeen healthy adults performed two bouts of 60 eccentric contractions with elbow flexor (EF group; n ​= ​9) or index finger abductor (IA group; n ​= ​8) muscles, separated by 1 week. All participants randomly performed eccentric exercise on either the right or left arm or hand muscles, and muscle damage markers and submaximal trapezoid contraction tests were conducted pre, post, 1- and 2-day post eccentric protocol. One week after the first bout, the same exercise protocol and measurements were performed on the contralateral muscles. Surface electromyographic (EMG) signals were collected from biceps brachii (BB) or first dorsal interosseous (FDI) during maximal and submaximal tests. The linear regression analyses were used to examine MU recruitment threshold versus mean firing rate and recruitment threshold versus derecruitment threshold relationships. EMG amplitude from BB (bout 1 vs. bout 2 ​= ​65.71% ​± ​22.92% vs. 43.05% ​± ​18.97%, p ​= ​0.015, d ​= ​1.077) and the y-intercept (group merged) from the MU recruitment threshold versus derecruitment threshold relationship (bout 1 vs. bout 2 ​= ​−7.10 ​± ​14.20 vs. 0.73 ​± ​16.24, p ​= ​0.029, d ​= ​0.513) at 50% MVIC were significantly different between two bouts. However, other muscle damage markers did not show any CL-RBE in both muscle groups. Therefore, despite changes in muscle excitation and MU firing behavior, our results do not support the existence of CL-RBE on BB and FDI muscles

Effect of Arm Eccentric Exercise on Muscle Damage of the Knee Flexors After High-Intensity Eccentric Exercise

Repeated bout effect (RBE) describes a phenomenon that an initial unaccustomed eccentric exercise (ECC) bout can confer a protective effect against muscle damage from the subsequent same exercise. This protection has been observed in the same muscle, as well as the contralateral homologous (CL-RBE) muscle. But it is unknown whether the RBE is evident for non-local unrelated heterogonous muscles. The purpose of this study was to examine whether an initial elbow flexion (EF) muscle-damaging ECC could confer RBE against muscle damage from the subsequent ECC performed in the remote lower limb knee flexor (KF) muscle group. Twenty-seven young individuals were randomly assigned into the experimental (EXP: n = 15) and the control (CON: n = 12) groups. All participants performed a baseline unilateral KF ECC (six sets of 10 repetitions) on a randomly chosen leg. After a washout period (4 weeks), the EXP group performed 60 high-intensity unilateral EF ECC on a randomly chosen arm, followed by the same intensity exercise using the contralateral KF muscle group 2 weeks later. The CON group performed the same contralateral KF ECC, but with no prior EF ECC bout. Changes in the KF muscle damage indirect markers (muscle soreness, range of motion, and maximal isometric strength) after the ECC were compared between the baseline and second bouts for both groups with mixed factorial three-way (group × bout × time) ANOVA. Additionally, index of protection for each damage marker was calculated at 1 and 2 days after the ECC and compared between groups with independent t-tests. For both groups, the magnitude of the changes in the damage markers between the baseline and the second ECC bouts were not significantly different (all values of p \u3e 0.05). As for the index of protection, relative to the CON, the EXP showed an exacerbating damaging effect on the KF isometric strength following the second ECC bout, particularly at the 1-day post-exercise time point (index of protection: EXP vs. CON mean ± SD = −29.36 ± 29.21 vs. 55.28 ± 23.83%, p = 0.040). Therefore, our results do not support the existence of non-local RBE

Downhill running impairs peripheral but not central neuromuscular indices in elbow flexor muscles

The purpose of this study was to examine the effects of a 1-h downhill running exercise on the elbow flexor muscles’ neuromuscular functions. Seventeen adults (Control [CON]: n = 9; Experimental [EXP]: n = 8) completed this study. The CON rested for 30 min while the EXP performed the downhill running. Before, 10 min, 24 h, and 48 h after the interventions, dependent variables (knee extensor muscle soreness, elbow flexion and knee extension isometric strength, elbow flexion resting twitch and voluntary activation [VA], and the biceps surface electromyography [EMG] amplitude) were measured. Knee extensor muscle soreness was significantly greater in the EXP than the CON group following the intervention throughout the entire 48 h. This was accompanied by the greater decline in the knee extension strength in the EXP than the CON (mean ± SD: -6.9 ± 3.4% vs. 1.0 ± 3.2%, p = 0.044). The elbow flexion strength, VA, and EMG amplitude were not affected by the exercise. However, the decline of the elbow flexion resting twitch was greater in the EXP than the CON (−19.6 ± 6.3% vs. 8.7 ± 5.9%, p = 0.003). Therefore, the downhill running impaired the remote elbow flexor muscles at a peripheral level

Cartilage regeneration using human umbilical cord blood derived mesenchymal stem cells: A systematic review and meta-analysis

Background and Objectives: Human umbilical-cord-blood-derived mesenchymal stem cells (hUCB-MSCs) have recently been used in clinical cartilage regeneration procedures with the expectation of improved regeneration capacity. However, the number of studies using hUCB-MSCs is still insufficient, and long-term follow-up results after use are insufficient, indicating the need for additional data and research. We have attempted to prove the efficacy and safety of hUCB-MSC treatment in a comprehensive analysis by including all subjects with knee articular cartilage defect or osteoarthritis who have undergone cartilage repair surgery using hUCB-MSCs. We conducted a meta-analysis and demonstrated efficacy and safety based on a systematic review. Materials and Methods: This systematic review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. For this study, we searched the PubMed, Embase, Web of Science, Scopus, and Cochrane Library literature databases up to June 2022. A total of seven studies were included, and quality assessment was performed for each included study using the Newcastle–Ottawa Quality Assessment Scale. Statistical analysis was performed on the extracted pooled clinical outcome data, and subgroup analyses were completed. Results: A total of 570 patients were included in the analysis. In pooled analysis, the final follow-up International Knee Documentation Committee (IKDC) score showed a significant increase (mean difference (MD), −32.82; 95% confidence interval (CI), −38.32 to −27.32; p < 0.00001) with significant heterogeneity (I2 = 93%, p < 0.00001) compared to the preoperative score. The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores at final follow-up were significantly decreased (MD, 30.73; 95% CI, 24.10–37.36; p < 0.00001) compared to the preoperative scores, with significant heterogeneity (I2 = 95%, p < 0.00001). The visual analog scale (VAS) score at final follow-up was significantly decreased (MD, 4.81; 95% CI, 3.17–6.46; p < 0.00001) compared to the preoperative score, with significant heterogeneity (I2 = 98%, p < 0.00001). Two studies evaluated the modified Magnetic Resonance Observation of Cartilage Repair Tissue (M-MOCART) score and confirmed sufficient improvement. In a study analyzing a group treated with bone marrow aspiration concentrate (BMAC), there was no significant difference in clinical outcome or M-MOCART score, and the post-treatment International Cartilage Repair Society (ICRS) grade increased. Conclusion: This analysis demonstrated the safety, efficacy, and quality of repaired cartilage following hUCB-MSC therapy. However, there was no clear difference in the comparison with BMAC. In the future, comparative studies with other stem cell therapies or cartilage repair procedures should be published to support the superior effect of hUCB-MSC therapy to improve treatment of cartilage defect or osteoarthritis

Decreased Angiopoietin Expression in Underactive Bladder Induced by Long-term Bladder Outlet Obstruction

Purpose Ischemia of the bladder can occur if neovascular formation cannot keep pace with hypoxia induced by chronic bladder outlet obstruction (BOO). The aim of this study was to examine changes in angiogenesis growth factor expression generated by chronic BOO in a rat model of underactive bladder. Methods Twenty female Sprague-Dawley rats aged 6 weeks were assigned to 4 groups (5 rats per group). Group 1 was the control. Group 2 underwent sham surgery. The rats in groups 3 and 4 underwent BOO and were followed up for 1 week and 8 weeks. Cystometry was carried out together with bladder tissue analysis at 1 week and 8 weeks postoperatively. Real-time polymerase chain reaction (PCR) assays were conducted to determine the expression level of angiogenesis-related growth factors. A hypoxia signaling pathway PCR array was additionally carried out. Results The group that underwent BOO for 8 weeks showed abnormal bladder function, with a diminished intercontraction interval, decreased maximal voiding pressure, and higher volume of residual urine (P<0.05). Hypoxia-inducible factor-1 alpha expression was elevated in this group. The expression levels of vascular endothelial growth factor (VEGF) and VEGF receptor messenger RNA (mRNA) in the BOO group were comparable to those in the control group. However, angiotensin/tie receptor mRNA expression levels increased at 1 week after BOO, but decreased at 8 weeks after BOO. In animals that underwent BOO, fewer blood vessels exhibited positive immunofluorescent staining for von Willebrand factor. Alterations were also seen in the hypoxia signaling pathway PCR array. Conclusions In a rat model of underactive bladder caused by surgical BOO, reduced angiopoietin expression was demonstrated. This observation might underlie visceral ischemia and fibrosis associated with the procedure. The findings of this study might offer an improved understanding of the disease processes underlying BOO and facilitate selection of the appropriate time to repair the organ in this condition

Differential Gene Expression in the Penile Cavernosum of Streptozotocin-Induced Diabetic Rats

Purpose Men with diabetes mellitus (DM) often present with severe erectile dysfunction (ED). This ED is less responsive to current pharmacological therapies. If we know the upregulated or downregulated genes of diabetic ED, we can inhibit or enhance the expression of such genes through RNA or gene overexpression. Methods To investigate gene changes associated with ED in type 1 DM, we examined the alterations of gene expression in the cavernosum of streptozotocin-induced diabetic rats. Specifically, we considered 11,636 genes (9,623 upregulated and 2,013 downregulated) to be differentially expressed in the diabetic rat cavernosum group (n=4) compared to the control group (n=4). The analysis of differentially expressed genes using the gene ontology (GO) classification indicated that the following were enriched: downregulated genes such as cell cycle, extracellular matrix, glycosylphosphatidylinositol-anchor biosynthesis and upregulated genes such as calcium signaling, neurotrophin signaling, apoptosis, arginine and proline metabolism, gap junction, transforming growth factor-β signaling, tight junction, vascular smooth muscle contraction, and vascular endothelial growth factor (VEGF) signaling. We examined a more than 2-fold upregulated or downregulated change in expression, using real time polymerase chain reaction. Analysis of differentially expressed genes, using the GO classification, indicated the enrichment Results Of the 41,105 genes initially considered, statistical filtering of the array analysis showed 9,623 upregulated genes and 2,013 downregulated genes with at least 2-fold changes in expression (P<0.05). With Bonferroni correction, SLC2A9 (solute carrier family 2 member 9), LRRC20 (leucine rick repeat containing 20), PLK1 (polo like kinase 1), and AATK (apoptosis-associated tyrosine kinase) were all 2-fold changed genes. Conclusions This study broadens the scope of candidate genes that may be relevant to the pathophysiology of diabetic ED. In particular, their enhancement or inhibition could represent a novel treatment for diabetic ED

Hepatoprotective and Antioxidative Activities of Cornus officinalis against Acetaminophen-Induced Hepatotoxicity in Mice

The fruit of Cornus officinalis Sieb. et Zucc. is commonly prescribed in Asian countries as a tonic formula. In this study, the hepatoprotective effect of ethanolic extracts of the fruit of C. officinalis (ECO) was investigated in a mouse model of acetaminophen- (APAP-) induced liver injury. Pretreatment of mice with ECO (100, 250, and 500 mg/kg for 7 days) significantly prevented the APAP (200 mg/kg) induced hepatic damage as indicated by the serum marker enzymes (AST, ALT, and LDH). Parallel to these changes, ECO treatment also prevented APAP-induced oxidative stress in the mice liver by inhibiting lipid peroxidation (MDA) and restoring the levels of antioxidant enzymes (SOD, CAT, and HO-1) and glutathione. Liver injury and collagen accumulation were assessed using histological studies by hematoxylin and eosin staining. Our results indicate that ECO can prevent hepatic injuries associated with APAP-induced hepatotoxicity by preventing or alleviating oxidative stress