Regeneration of excised shell by the invasive apple snail Pomacea canaliculata

After excision of shell from Pomacea canaliculata, survival rates, repair process, haemocyte response, and calcium content were observed and quantified for three weeks. The following experimental treatments were used: black-colored individuals with large (BL-group) or small (BS-group) shell heights, yellow-colored individuals with large (YL-group) or small (YS-group) shell heights. The survival rates in BL-, YL-, BS-, and YS-groups after making partial excisions of snail shells were, respectively, 93.59, 94.87, 92.31, and 96.15%. Freshly regenerated shell could be seen at 1 day among the four groups after induction of shell regeneration. Regeneration shell filled the wound after 5–10 days. The area of regenerated shell in yellow-colored individuals was larger than that of black-colored individuals, but the thickness of regenerated shell was not significantly different. Multiple (four times) inductions of shell regeneration significantly enhanced the thickness of newly formed shells. Two types of circulating haemocytes (hyalinocytes and granulocytes) were identified under light microscopy based on Wright’s staining. Artificial induction of shell regeneration rendered a significant increase in the number of total circulating haemocytes which was followed by a decrease to pre-wounding levels. This peak value of total circulating haemocytes was 2.86, 2.43, 1.69, and 1.71-fold higher than pre-wounding levels in group BL, YL, BS, and YS, respectively. The number of total circulating haemocytes in yellow-colored individuals was significantly higher than in black-colored. Calcium concentrations in the mantles of snails are favorable for calcium nucleation. It is postulated that calcium content increased in the mantle increase at the start of the experiment and then returned to pre-wounding levels at the end of the experiment. This study shows that apple snails have effective shell regeneration abilities and that haemocytes and calcium transportation appear to play an important role in shell growth and regeneration.     

A multi-body dynamics study on a weight-drop test of rat brain injury

Traumatic brain injury (TBI), induced by impact of an object with the head, is a major health problem worldwide. Rats are a well-established animal analogue for study of TBI and the weight-drop impact-acceleration (WDIA) method is a well-established model in rats for creating diffuse TBI, the most common form of TBI seen in humans. However, little is known of the biomechanics of the WDIA method and, to address this, we have developed a four-degrees-of-freedom multi-body mass-spring-damper model for the WDIA test in rats. An analytical expression of the maximum skull acceleration, one of the important head injury predictor, was derived and it shows that the maximum skull acceleration is proportional to the impact velocity but independent of the impactor mass. Furthermore, a dimensional analysis disclosed that the maximum force on the brain and maximum relative displacement between brain and skull are also linearly proportional to impact velocity. Additionally, the effects of the impactor mass were examined through a parametric study from the developed multi-body dynamics model. It was found that increasing impactor mass increased these two brain injury predictors.     

Electromyographic analysis of rotator cuff muscles in patients with rotator cuff tendinopathy: A systematic review

The shoulder is inherently an unstable joint which heavily relies on the neuromuscular activation of the rotator cuff (RC) complex for stability during movement. Currently, there is no consensus regarding how the activity of RC muscles is affected among individuals with a RC tendinopathy (RCTe). This study reviewed the evidence of studies comparing the electromyographic (EMG) activity of any RC muscle of shoulders with a symptomatic RCTe to asymptomatic shoulders. Eight databases were searched. Data from 343 participants (201 symptomatic and 209 asymptomatic shoulders) were analyzed from 10 out of 402 included studies. Strong evidence for the infraspinatus and supraspinatus during isometric contractions and limited evidence for the supraspinatus and infraspinatus during isokinetic contractions suggest that the muscular activity is not altered among individuals with a RCTe during these types of contraction. Very limited evidence indicates reduced muscle activity for the infraspinatus and subscapularis in the presence of a RCTe during isotonic contractions, and no alterations for the supraspinatus or teres minor were identified. Lastly, conflicting to moderate evidence suggests alterations in RC muscle activity during unrestrained movements and swimming. These findings indicate that EMG deficits associated with a RCTe can best be appreciated during unrestrained movements.     

Involvement of Nox2 and Nox4 NADPH oxidases in early brain injury after subarachnoid hemorrhage

Oxidative stress is responsible for a poor prognosis of subarachnoid hemorrhage (SAH) patients. Nox2 has been shown to participate in SAH-induced early brain injury (EBI). Nox4 is another major subtype of Nox family widely expressed in central nervous system (CNS). Here, we investigated the role of Nox4 and whether there was a synergistic effect of Nox2 and Nox4 in SAH-induced EBI. Clinical brain biopsies of four patients with traumatic brain injury (TBI) and perihematomal brain tissue from six subjects with SAH were examined. Gp91ds-tat (a specific inhibitor of Nox2), GKT137831 (a specific inhibitor of Nox4), and apocynin (a non-specific Nox inhibitor) were used to test the role of Nox2 and Nox4. The protein levels of Nox2 and Nox4 were elevated in rat neurons and astrocytes at 12?h after SAH, and in cultured brain microvascular endothelial cells at 24?h after exposure to OxyHb. Similarly, there were higher Nox2 and Nox4 protein levels in perihematomal neurons and astrocytes in SAH patients than that in brain tissue from subjects with TBI. In SAH rat model, gp91ds-tat and GKT137831 could reduce SAH-induced neuronal death and degeneration, whereas apocynin did not induce a more intense neuroprotection. Consistently, in in vitro SAH model, siRNA-mediated silencing of Nox2 and Nox4 suppressed the OxyHb-induced neuronal apoptosis, whereas Nox2 and Nox4 co-knockdown also did not show a remarkable overlay effect. In conclusion, Nox4 should contribute to the pathological processes in SAH-induced EBI, and there was not an overlay effect of Nox2 inhibition and Nox4 inhibition on preventing SAH-induced EBI.     

Neutral sphingomyelinase inhibition alleviates apoptosis,but not ER stress,in liver ischemia–reperfusion injury

Previous studies have revealed the activation of neutral sphingomyelinase (N-SMase)/ceramide pathway in hepatic tissue following warm liver ischemia reperfusion (IR) injury. Excessive ceramide accumulation is known to potentiate apoptotic stimuli and a link between apoptosis and endoplasmic reticulum (ER) stress has been established in hepatic IR injury. Thus, this study determined the role of selective N-SMase inhibition on ER stress and apoptotic markers in a rat model of liver IR injury. Selective N-SMase inhibitor was administered via intraperitoneal injections. Liver IR injury was created by clamping blood vessels supplying the median and left lateral hepatic lobes for 60?min, followed by 60?min reperfusion. Levels of sphingmyelin and ceramide in liver tissue were determined by an optimized multiple reactions monitoring (MRM) method using ultrafast-liquid chromatography (UFLC) coupled with tandem mass spectrometry (MS/MS). Spingomyelin levels were significantly increased in all IR groups compared with controls. Treatment with a specific N-SMase inhibitor significantly decreased all measured ceramides in IR injury. A significant increase was observed in ER stress markers C/EBP-homologous protein (CHOP) and 78?kDa glucose-regulated protein (GRP78) in IR injury, which was not significantly altered by N-SMase inhibition. Inhibition of N-SMase caused a significant reduction in phospho-NF-kB levels, hepatic TUNEL staining, cytosolic cytochrome c, and caspase-3, -8, and -9 activities which were significantly increased in IR injury. Data herein confirm the role of ceramide in increased apoptotic cell death and highlight the protective effect of N-SMase inhibition in down-regulation of apoptotic stimuli responses occurring in hepatic IR injury.     

The neuronal differentiation microenvironment is essential for spinal cord injury repair

Spinal cord injury (SCI) often leads to substantial disability due to loss of motor function and sensation below the lesion. Neural stem cells (NSCs) are a promising strategy for SCI repair. However, NSCs rarely differentiate into neurons; they mostly differentiate into astrocytes because of the adverse microenvironment present after SCI. We have shown that myelin-associated inhibitors (MAIs) inhibited neuronal differentiation of NSCs. Given that MAIs activate epidermal growth factor receptor (EGFR) signaling, we used a collagen scaffold-tethered anti-EGFR antibody to attenuate the inhibitory effects of MAIs and create a neuronal differentiation microenvironment for SCI repair. The collagen scaffold modified with anti-EGFR antibody prevented the inhibition of NSC neuronal differentiation by myelin. After transplantation into completely transected SCI animals, the scaffold-linked antibodies induced production of nascent neurons from endogenous and transplanted NSCs, which rebuilt the neuronal relay by forming connections with each other or host neurons to transmit electrophysiological signals and promote functional recovery. Thus, a scaffold-based strategy for rebuilding the neuronal differentiation microenvironment could be useful for SCI repair.     

Restoring diabetes-induced autophagic flux arrest in ischemic/reperfused heart by ADIPOR (adiponectin receptor) activation involves both AMPK-dependent and AMPK-independent signaling

Macroautophagy/autophagy is increasingly recognized as an important regulator of myocardial ischemia-reperfusion (MI-R) injury. However, whether and how diabetes may alter autophagy in response to MI-R remains unknown. Deficiency of ADIPOQ, a cardioprotective molecule, markedly increases MI-R injury. However, the role of diabetic hypoadiponectinemia in cardiac autophagy alteration after MI-R is unclear. Utilizing normal control (NC), high-fat-diet-induced diabetes, and Adipoq knockout (adipoq^?/?) mice, we demonstrated that autophagosome formation was modestly inhibited and autophagosome clearance was markedly impaired in the diabetic heart subjected to MI-R. adipoq^?/? largely reproduced the phenotypic alterations observed in the ischemic-reperfused diabetic heart. Treatment of diabetic and adipoq^?/? mice with AdipoRon, a novel ADIPOR (adiponectin receptor) agonist, stimulated autophagosome formation, markedly increased autophagosome clearance, reduced infarct size, and improved cardiac function (P < 0.01 vs vehicle). Mechanistically, AdipoRon caused significant phosphorylation of AMPK-BECN1 (Ser93/Thr119)-class III PtdIns3K (Ser164) and enhanced lysosome protein LAMP2 expression both in vivo and in isolated adult cardiomyocytes. Pharmacological AMPK inhibition or genetic Prkaa2 mutation abolished AdipoRon-induced BECN1 (Ser93/Thr119)-PtdIns3K (Ser164) phosphorylation and AdipoRon-stimulated autophagosome formation. However, AdipoRon-induced LAMP2 expression, AdipoRon-stimulated autophagosome clearance, and AdipoRon-suppressed superoxide generation were not affected by AMPK inhibition. Treatment with MnTMPyP (a superoxide scavenger) increased LAMP2 expression and stimulated autophagosome clearance in simulated ischemic-reperfused cardiomyocytes. However, no additive effect between AdipoRon and MnTMPyP was observed. Collectively, these results demonstrate that hypoadiponectinemia impairs autophagic flux, contributing to enhanced MI-R injury in the diabetic state. ADIPOR activation restores AMPK-mediated autophagosome formation and antioxidant-mediated autophagosome clearance, representing a novel intervention effective against MI-R injury in diabetic conditions.     

基于自组装交联的水凝胶在皮肤损伤中的应用

自组装水凝胶具有高吸水性、高保水性、良好的生物相容性、生物降解性和三维立体结构等物理优势,同时具备止血、抗菌、抗炎、抗氧化等功能优势。因此自组装水凝胶作为一种新型伤口敷料,在皮肤损伤的创面愈合和调节再生中具有广阔的应用前景。本文通过分析讨论自组装水凝胶的交联机制,阐述自组装水凝胶的功能,明确其作为伤口敷料在皮肤损伤中的优势,总结自组装水凝胶在皮肤损伤应用中的发展趋势,展望自组装水凝胶的未来方向,有助于更全面地了解自组装水凝胶,为自组装水凝胶的多技术联合应用提供新思路。     

Improvement in Double Staining With Fluoro-Jade C and Fluorescent Immunostaining: FJC Staining Is Not Specific to Degenerating Mature Neurons

Fluoro-Jade C (FJC) staining has been used to detect degenerating neurons in tissue sections. It is a simple and easy staining procedure and does not depend on the manner of cell death. In some experiments, double staining with FJC and fluorescent immunostaining (FI) is required to identify cell types. However, pretreatment for FJC staining contains some processes that are harsh to fluorophores, and the FI signal is greatly reduced. To overcome this issue, we improved the double staining protocol to acquire clear double-stained images by introducing the labeled streptavidin–biotin system. In addition, several studies indicate that FJC can label non-degenerating glial cells, including resting/reactive astrocytes and activated microglia. Moreover, our previous study indicated that degenerating mesenchymal cells were also labeled by FJC, but it is still unclear whether FJC can label degenerating glial cells. Acute encephalopathy model mice contained damaged astrocytes with clasmatodendrosis, and 6-aminonicotinamide-injected mice contained necrotic astrocytes and oligodendrocytes. Using our improved double staining protocol with FJC and FI, we detected FJC-labeled degenerating astrocytes and oligodendrocytes with pyknotic nuclei. These results indicate that FJC is not specific to degenerating neurons in some experimental conditions: