Physiology international最新文献

Background/aim: This study aimed to compare electrophysiological hearing thresholds in guinea pigs exposed to intra-cochlear trauma using the continuous loop deconvolution averaging method (CLAD) and quasi-auditory steady state responses (QASSR).

Material and methods: Eight guinea pigs were implanted with electrodes at the lambda point. Intra-cochlear trauma was induced via electrode insertion. Hearing thresholds and amplitudes at 0.5, 1, 4, and 16 kHz were recorded using CLAD and QASSR methods. Recordings from the lambda electrode were compared with those from a conventional retro-auricular needle electrode.

Results: The lambda electrode demonstrated significantly lower mean auditory thresholds at all tested frequencies compared to the retro-auricular needle electrode in both trauma and non-trauma groups (P < 0.05). Amplitude comparisons revealed statistically significant differences at 1 kHz in the trauma group, and at 4 and 16 kHz in both trauma and non-trauma groups (P < 0.05).

Conclusion: The QASSR technique, coupled with chronic lambda electrode implantation, provides an effective method for estimating hearing loss induced by intra-cochlear trauma in guinea pigs.

Triathlon is a very complex sport, as the athlete has to master the characteristics of three sports (swimming, cycling and running), and the tasks of coaches are increased by the need to get the most out of all three. This sport improves endurance, has a positive effect on muscle development, movement coordination, breathing, and circulation.For talent identification factors determining the performance in triathlon are essential (physiological, anthropometric, psychosocial and tactical factors).Scientific literature concerning performance in triathlon sport is rather scarce. Although there are some studies in this field, there is little comprehensive literature analyzing training of youth athletes. The aim of our research was (i) to conduct a targeted literature review of the body composition and performance of youth triathletes and (ii) comparing results with those of elite adults, (iii) determining factors playing a prominent role in the selection and performance of triathletes.The results of our research reveal that factors like the appropriate competition age (approx. 28-30 years for both sexes), anthropometric parameters (it is necessary to take into account the distance the athlete covers) and performance criteria (the most important is VO2max) are essential for successful selection and subsequent success.In the world of triathlon constant regulatory changes and the need to adapt new competitive demands necessitate keeping our knowledge up to date.

The mechanical efficiency of the quadriceps femoris muscle-tendon unit likely depends on its structural and mechanical properties. Therefore, the purpose of this study was to assess the mechanical efficiency in vivo under various stretch-shortening cycle conditions and to investigate how the morphological and mechanical properties of the quadriceps femoris influence mechanical efficiency.We used MRI to measure quadriceps femoris muscle and tendon morphological properties in young females (n = 9), and we determined mechanical efficiency during stretch-shortening cycle contractions using computer-controlled dynamometer. Testing protocol included contractions with moderate and maximal pretension level and stretching loads of 20 and 100J.Greater mechanical efficiency was associated with larger knee flexion angles and increased positive work under moderate pretension levels with both 20 J (r = 0.67, P = 0.045; r = 0.82, P = 0.007) and 100 J stretch loads (r = 0.87, P = 0.006; r = 0.82, P = 0.007).These findings suggest that lower stretching loads enhance muscle-tendon interaction efficiency by favoring tendon elongation during muscle-tendon unit lengthening, resulting in higher mechanical efficiency. No morphological or mechanical parameter of the muscle-tendon unit were linked to mechanical efficiency, suggesting that efficiency may depend more on muscle activation patterns than on structure.

Introduction: Fatigue accumulation in the final 100 m of a 400-m sprint impairs neuromuscular coordination and biomechanics, often resulting in performance decline. This study investigated how fatigue affects lower-limb coordination, joint mechanics, and recovery patterns in competitive sprinters.

Methods: A randomized controlled trial was conducted with 30 trained male Chinese 400-m sprinters (age: 29.8 ± 2.7 years), allocated into control (n = 15) and experimental (n = 15) groups. The experimental group completed five 80-m maximal sprints with decreasing rest intervals before running a 400-m sprint; the control group performed only the 400-m sprint. Kinematic and EMG data were recorded during the final 100 m. Recovery measures-Rating of Perceived Exertion (RPE), Jump Height, Peak Force, and Peak Power-were assessed at 30 min, 1 h, 3 h, and 36 h post-sprint. Data were analysed using two-way ANOVA and paired t-tests.

Results: Fatigue significantly increased stride variability in the experimental group from 0.022 ± 0.010 m (Session I) to 0.035 ± 0.012 m (Session II, P < 0.0001), while hip flexion decreased from 33.1 ± 4.5° to 26.7 ± 3.9° (P = 0.0012), and CRP rose from 15.6 ± 2.9° to 24.1 ± 4.2° (P = 0.002). EMG activation declined in key muscles, including Rectus Femoris (0.28 ± 0.05 to 0.23 ± 0.05, P = 0.0035) and Soleus (0.21 ± 0.05 to 0.18 ± 0.04, P = 0.0003). RPE increased from 10.9 ± 2.05 to 19.5 ± 1.20 at 30 min post-sprint (P < 0.0001), with Jump Height decreasing from 49.5 ± 5.02 cm to 34.8 ± 5.10 cm (P < 0.0001), Peak Force from 17.8 ± 1.28 to 15.1 ± 1.42 N kg-1 (P = 0.0012), and Peak Power from 65.7 ± 6.03 to 50.4 ± 4.95 W kg-1 (P < 0.0001).

Conclusion: Fatigue in the final sprint phase significantly impairs joint coordination, muscle activation, and power output. These findings highlight the need for targeted fatigue-resistance training and individualized recovery protocols. A limitation is the all-male sample, which may affect generalizability.

Introduction: Gestational diabetes mellitus (GDM) is an endocrine-metabolic disorder that develops during pregnancy. Glucose transporters (GLUTs), which facilitate the transport of glucose across the plasma membrane (facilitated diffusion) play a key role in the progression of this disease.

Objective: This study aimed to analyze the general characteristics and expression of GLUTs in GDM.

Methods: This systematic review was performed following the PRISMA guidelines. A literature search was performed without language restrictions using the PubMed, Web of Science, Redalyc, Google Scholar, Cochrane, and Scopus databases between 2010 and 2023 using the keywords GLUT, Gestational diabetes mellitus, GDM and GLUT, Glucose metabolism and GLUT, Glucose receptors to identify most human studies, as the majorityof studies use murine models, focusing on a positive diagnosis of GDM.

Results: A total of 36 articles were included in this review. Of the 36 articles, 21 described the general characteristics of GLUTs, and 15 were scientific reports (12 in humans and 3 in animals). The studies showed that interleukin-2, tumor necrosis factor-α, and leptin correlated negatively with the expression of GLUT1 in patients with GDM. The three murine studies showed that hyperglycemia was associated with decreased GLUT2 expression.

Conclusions: Evidence of GLUT expression at the gestational stage provides a better understanding of fetal life conditions and how they contribute to the development of GDM. Therefore, analyzing GLUT expression serves as a preventive measure.

Exercise-induced fatigue and inflammation can significantly impair athletic performance and recovery. Effective strategies to mitigate these effects are critical for athletes and those engaged in high-intensity physical activities. Anti-inflammatory properties have been associated with Antarctic krill oil (AKO), which contains n-3 polyunsaturated fatty acids (n-3 PUFA) such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). After exhaustive exercise, this study examined how 4-week AKO supplementation affected skeletal muscle inflammation and the TLR4/MyD88/NF-κB signaling pathways in mice. Sixty male SPF-grade 8-week-old C57BL/6J mice were randomly assigned to four groups: soybean oil control (BO-C), AKO control (KO-C), soybean oil exercise (BO-E), and AKO exercise (KO-E). The KO groups received 200 mg/kg/BW AKO intragastrically for four weeks, while the BO groups received an equivalent volume of soybean oil. After the supplementation period, the exercise groups underwent a strenuous treadmill exercise. Grasping force was measured at 0 h, 6 h, 24 h, 48 h, and 72 h post-exercise, and tissue samples were analyzed histologically and biochemically. Results showed that AKO significantly reduced body weight and enhanced exercise endurance and recovery. Furthermore, serum CK, LDH and CRP levels, as well as muscle TNF-α concentrations, and TLR4 and MyD88 protein expressions were lower in the KO-E group than in the BO-E group. As a result of modulating the TLR4/MyD88/NF-κB signaling pathway through AKO supplementation, it decreases inflammation after exhaustive exercise and promotes recovery.

Background: Adipose-derived stem cell (ADSC) derived exosomes have been widely studied in disease treatment. Exosomes are able to deliver bioactive molecules, including non-coding RNAs and proteins. Long non-coding RNAs (lncRNAs) are non-coding RNAs longer than 200 nucleotides and are enriched in exosomes. This work aimed to explore the effects of lncRNA KLF3 antisense RNA 1 (KLF3-AS1) that delivered by ADSC-derived exosomes on ovarian aging.

Methods: ADSCs were isolated and characterized with the surface biomarkers. Exosomes were isolated from ADSCs. The biomarkers of ADSC-derived exosomes were identified using western blotting. Exosomes were labeled with PKH26 and internalized by primary granulosa cells (pGCs), and relative images were taken under fluorescence microscope. ADSCs were transfected with KLF3-AS1, and exosomes were isolated for treatment of aging female mice. The ovary weight was recorded. The follicular development was measured by Hematoxylin and eosin (H&E) staining and Masson's trichrome staining. Apoptosis of ovary tissues was detected by TUNEL assay. The senescence and apoptosis of pGCs were determined by S-β-gal staining kit and Annexin V/PI detection kit. RNA pulldown and RNA Immunoprecipitation Chip (RIP) assay were performed to determine the interaction of Y box binding protein 1 (YBX1) with KLF3-AS1.

Results: The ADSC-derived exosomes could deliver KLF3-AS1 to pGCs. Treatment with ADSC-derived exosomes notably elevated the ovary weight and enhanced follicular development in aged mice, whereas depletion of KLF3-AS1 reversed these effects and promoted cell apoptosis. ADSCs-derived exosomes alleviated senescence and apoptosis of pGCs, while KLF3-AS1 depletion blocked these phenotypes. KLF3-AS1 directly interacts with YBX1. KLF3-AS1 depletion inhibited phosphorylation of PI3K, Akt, and mTOR in pGC, and overexpression of YBX1 reversed these phenotypes.

Conclusion: ADSC-derived exosomal KLF3-AS1 could improve ovary aging and enhance pGC viability via targeting the YBX1 and PI3K/AKT/mTOR signaling.

Objective: Although SARS-CoV-2 primarily targets the respiratory system, there is evidence that it can also infect the central nervous system, especially in children, leading to neurological symptoms and long-term consequences. It is imperative to summarize the possible mechanisms, main symptoms, and treatments of neurological symptoms of COVID-19 in children.

Methods: We performed a literature search using the PubMed online database to find studies investigating the mechanisms of COVID-19 infection of the central nervous system and therapies for COVID-19 neurological symptoms in children.

Results: The main mechanisms of action of SARS-CoV-2 virus on the nervous system are direct invasion, systemic inflammation and molecular mimicry. Although the incidence of adverse reactions to intravenous IgG therapy (IVIG) varies greatly and the contraindications are not yet clear, IVIG has been shown to be clearly effective for the neurological symptoms of COVID-19 in children.

Conclusion: However, due to insufficient data, more clinical studies are still needed to confirm its safety and efficacy, further improve the treatment plan, and determine the appropriate dosage to better serve clinical practice.

Significance: The specific regimen of IVIG treatment for COVID-19 in children was explored, which further improved the understanding of COVID-19 and L-C19 neurological diseases in children.

Objective: This study aimed to investigate the role of levetiracetam (LEV) and gabapentin (GBP) on mechanical and thermal pain thresholds, as well as n-acetylcysteine (NAC) as an adjuvant, in the pentylenetetrazol (PTZ)-induced post-traumatic epilepsy (PTE) model after mild-traumatic brain injury (TBI) in male Sprague-Dawley rats.

Methods: Animals were randomly divided into 7 groups (Control, PTE, PTE+LEV, PTE+GBP, PTE+NAC, PTE+LEV+NAC and PTE+GBP+NAC). Rats received 50 mg kg-1 LEV, 100 mg kg-1 GBP, and combinations of these antiepileptics with 100 mg kg-1 NAC for 14 days after TBI.

Results: While the thermal pain threshold decreased significantly in the PTE group (P < 0.05), it increased in the PTE+LEV, PTE+GBP, and PTE+LEV+NAC groups (P < 0.05, P < 0.001 and P < 0.01, respectively). Interestingly, NAC alone did not affect the thermal pain threshold, but the combination of PTE+LEV+NAC increased the thermal pain threshold. Furthermore, PTE+GBP+NAC administration prevented the effect of GBP on the thermal pain threshold.

Conclusions: The presented study is the first to examine the effect of LEV and GBP in PTE. It was found that PTE decreased the thermal pain threshold, but LEV and GBP applied for 14 days prevented the decrease in PTE-related pain threshold and increased the thermal pain threshold. NAC, which was used as an adjuvant to support antiepileptic drugs, did not influence the thermal pain threshold alone; however, it increased the pain threshold more by potentiating the effect of LEV. Both LEV and GBP have an antihyperalgesic effect in the PTE model facilitated by PTZ, and NAC further reinforces the antihyperalgesic effect of LEV.