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Integrative analysis of transcriptome and DNA methylome dynamics during caudal fin regeneration in silver pomfret (Pampus argenteus).

Caudal fin regeneration in teleost fish is a complex, multi-stage process involving coordinated molecular and cellular changes. While the role of epigenetic regulation particularly DNA methylation has been studied in model freshwater species such as zebrafish, its contribution to regeneration in marine teleosts remains largely unexplored. In this study, we integrated transcriptomic and DNA methylomic data to characterize the temporal dynamics of gene expression and methylation during caudal fin regeneration in the silver pomfret (Pampus argenteus). Using RNA-sequencing and reduced representation bisulfite sequencing (RRBS) at three biologically critical time points 1, 3, and 7 days post-amputation (dpa), we characterized the spatiotemporal molecular landscape of caudal fin regeneration. These time points capture the key transitional phases of wound healing and inflammation (1 dpa), blastema formation and progenitor proliferation (3 dpa), and regenerative outgrowth with tissue remodeling (7 dpa), enabling robust detection of the major molecular programs underlying epimorphic regeneration. Concurrently, CG-methylome analysis identified thousands of dynamically changing differentially methylated regions (DMRs). A strong global inverse correlation was observed between promoter methylation and gene expression. Integrative analysis pinpointed key regeneration genes (fgf20a, msxb, sox9b) whose expression was associated with dynamic methylation changes in their promoters or gene bodies. We conclude that DNA methylation is a dynamic and key regulatory layer that acts in concert with transcriptional reprogramming to coordinate tissue regeneration, providing new insights into the epigenetic mechanisms underlying complex regenerative processes in teleosts.

Animals

Transcriptome analysis of the pectoral fin degeneration in half-smooth tongue sole (Cynoglossus semilaevis).

Appendage degeneration is a notable morphological feature of some teleosts with specialized benthic lifestyles. The half-smooth tongue sole (Cynoglossus semilaevis) undergoes severe pectoral fin regression during metamorphosis. However, the molecular basis underlying rapid pectoral fin degeneration remains unclear. Here, we performed time-series transcriptome sequencing on pectoral fins at pre-metamorphosis, metamorphosis peak and post-metamorphosis to characterize the molecular changes associated with pectoral fin degeneration. Transcriptional dynamics and functional enrichment showed that no significant enrichment of classical apoptosis-related transcriptional pathways was detected during pectoral fin degeneration. Instead, sustained downregulation of twist1b, identified as a transcriptomic candidate, together with significant upregulation of ssh1, coupled with enrichment of lysosome and ubiquitin-proteasome system (UPS) pathways, suggested enhanced tissue remodeling during pectoral fin degeneration. Temporal expression clustering revealed heterochronic misalignment in the developmental gene expression: upstream initiator tbx5 was upregulated at early metamorphosis, while downstream maintenance signal fgf10 decreased synchronously. Distal patterning gene hoxd12a exhibited premature expression and rapid decay, losing sustained late-phase expression. Moreover, transient elevation of gli3 during metamorphosis may contribute to restricted distal fin growth. We conclude that pectoral fin degeneration in C. semilaevis is associated with heterochronic disruption of developmental signaling and extensive tissue remodeling. This study provides transcriptomic insights into pectoral fin degeneration in tongue soles and establishes a basis for future functional studies of appendage reduction in teleosts.

Animals

Comparative analysis of histological and transcriptomic characteristics in caudal muscles of nile crocodiles (Crocodylus niloticus), siamese crocodiles (Crocodylus siamensis), and their hybrids.

Crocodylus niloticus and Crocodylus siamensis are high-value aquaculture species. C. niloticus is large-bodied but less abundant, while C. siamensis grows fast but is small-sized. Their hybrids combine parental advantages, yet relevant research is scarce. This study compared the histological and transcriptomic characteristics of the caudal muscle across the three taxa. HE staining indicated that C. niloticus had significantly larger myofiber diameters (p&#xa0;<&#xa0;0.05); C. siamensis had the smallest, and the myofiber density of hybrids was much closer to that of C. siamensis. Masson's trichrome staining indicated that C. niloticus had the thickest collagen fibers (p&#xa0;<&#xa0;0.05), C. siamensis the thinnest, and hybrids exhibited highly similar histological traits to C. siamensis. C. niloticus had higher LDH and SDH activities in caudal muscles, whereas the hybrid crocodile indicated the highest CK activity. Transcriptomic analysis identified numerous differentially expressed genes (DEGs), which were enriched in growth, muscle metabolism, and energy allocation pathways via GO/KEGG annotations. PPI analysis screened 24 hub genes related to energy metabolism. This study systematically reveals caudal muscle differences, providing insights into growth-related molecular mechanisms and theoretical support for crocodile artificial breeding.

Animals

No Efficacy of Dexamethasone Injections for Acute Sciatica: A Double-Blind Randomized Study Versus Saline.

BACKGROUND: The efficacy of caudal injections for patients with acute sciatica remains controversial. The DEXHIA study was designed to evaluate whether ultrasound-guided caudal injection of dexamethasone provides superior clinical outcomes compared with saline placebo. METHODS: This prospective, randomized, placebo-controlled, double-blind trial included adult patients with sciatica secondary to lumbar disc herniation of less than 3 months' duration. Participants were randomly assigned in a 1:1 ratio to receive either 16&#x2009;mg of dexamethasone (4&#x2009;mL) diluted with 16&#x2009;mL of saline (DEXA group) or 20&#x2009;mL of saline alone (PLACEBO group), administered by ultrasound-guided caudal epidural injection. The primary outcome was the change in the Oswestry Disability Index (ODI) at 3&#x2009;weeks. Secondary outcomes included leg pain and low back pain assessed by visual analogue scale (VAS), health-related quality of life (SF-36), need for repeat epidural injection, and need for lumbar surgery. Clinical assessments were performed at 3&#x2009;weeks, 3 months, and 6 months. RESULTS: A total of 106 patients were randomized, with 53 participants assigned to each treatment group. The primary endpoint was not met, as the improvement in ODI at 3&#x2009;weeks did not differ significantly between groups (mean change: -9.5&#x2009;&#xb1;&#x2009;4.4 in the DEXA group versus -13.8&#x2009;&#xb1;&#x2009;4.4 in the PLACEBO group; p&#x2009;=&#x2009;0.18). No significant differences were observed for any relevant secondary outcome at any follow-up time point. During the 6-month follow-up, 34 patients in the DEXA group and 30 patients in the PLACEBO group underwent a second, non-blinded injection of dexamethasone (ns). Lumbar surgery was performed in 10 patients in the DEXA group and nine patients in the PLACEBO group (ns). Injection-related adverse events were mild and transient but occurred more frequently in the DEXA group. CONCLUSIONS: Caudal injection of soluble dexamethasone conferred no clinical benefit over saline placebo in patients with acute sciatica. SIGNIFICANCE STATEMENT: Epidural injections are widely used worldwide for the treatment of resistant sciatica and have been extensively studied in multiple meta-analyses. However, their clinical value remains debated due to the limited methodological quality of most available studies. We conducted a methodologically rigorous randomized, placebo-controlled trial, which yielded negative results. These findings question the efficacy of caudal epidural injection of a non-particulate corticosteroid administered via a remote (sacrococcygeal) approach for disc-related sciatica. TRIAL REGISTRATION: The trial was registered under European Clinical Trials No. 2021-001571-17 and ClinicalTrials.gov identifier NCT05000658.

Adult

The radiographic effect of cage subsidence on neuroforamina after anterior cervical discectomy and fusion.

STUDY DESIGN: Retrospective Cohort Study. OBJECTIVE: The objective of this study is to investigate the effect of cage subsidence on neuroforaminal area after anterior cervical discectomy and fusion (ACDF) utilizing computed tomography (CT). SUMMARY OF BACKGROUND DATA: Restoration of disc height via implantation of an interbody device provides an indirect decompression of the cervical neuroforamina. Interbody cage subsidence is a potential postoperative occurrence, but the effect of this on neuroforaminal area has yet to be characterized. METHODS: A retrospective review was conducted of patients who underwent one- to four-levels of ACDF utilizing an interbody device with anterior plating. Cage subsidence, neuroforaminal area, height and width were measured on CT scans preoperatively and at least 6&#xa0;months postoperatively. Levels with a cumulative sum of cranial and caudal subsidence greater than 4&#xa0;mm were classified as severely subsided, while levels with cumulative subsidence less than 4&#xa0;mm were classified as non-severely subsided. RESULTS: A total of 83 patients (151 levels) were included in this retrospective analysis. Average endplate subsidence was 3.2&#xa0;&#xb1;&#xa0;1.9&#xa0;mm. Non-severely subsided levels demonstrated a greater perioperative increase in neuroforaminal area (7.9 vs 2.1&#xa0;mm2, p&#xa0;<&#xa0;0.001), neuroforaminal height (1.1 vs 0.4&#xa0;mm, p&#xa0;<&#xa0;0.001) and neuroforaminal width (0.7 vs 0.1&#xa0;mm, p&#xa0;<&#xa0;0.001) compared to severely subsided levels. Interbody subsidence significantly predicted a decreased change in neuroforaminal height, width and area (p&#xa0;<&#xa0;0.001). Severe subsidence was associated with an increased rate of pseudarthrosis, but similar reoperation rates and recurrent neurologic deficits between the two groups. CONCLUSIONS: Severe subsidence of interbody cages after an ACDF was associated with a decreased perioperative change in neuroforaminal dimensions. This decrease in the size of the neuroforamen may reduce the effect of indirect decompression of the nerve root.

Humans