Graft Interface Research Articles

Allogeneic abdominal non-vascularized rectus fascia transplantation without immunosuppression equals syngeneic transplantation in a rabbit model at short-term follow-up

Complex abdominal wall repair remains a major surgical challenge. In transplant patients, non-vascularized rectus fascia (NVRF) is successfully used to bridge the defect. To extrapolate this to non-transplant patients, we developed a rabbit model of NVRF-transplantation without immunosuppression comparing syngeneic versus allogeneic transplants. Short-term outcome (4 weeks) was evaluated macroscopically (ingrowth, seroma/hematoma, herniation, and infection), histologically at the graft interface and center (inflammation, neovascularization, and collagen deposition) and by mechanical testing. In both groups a similar macroscopic ingrowth of the NVRF was observed. In the syn-group, one seroma and one hematoma was seen. Two small herniations were detected at the suture line in the allo-group. No surgical site infections were observed. Histologically, graft neovascularization was observed in all animals. Infiltration of T-lymphocytes was seen at the graft interface in both groups, but more in the allo-group (p < 0.0001). Deposition of collagen was not different between groups. Macrophages were present in both groups around sutures and in the center more abundantly in the allo-group (p = 0.0001). Graft stiffness and strength were similar for both groups. With this model, we showed that allogeneic transplantation without immunosuppression results in favorable short-term inflammatory and mechanical outcomes. Long-term experiments are needed to further evaluate the effect on graft integration and hernia development.

An Integrated Analysis of Anatomical and Sugar Contents Identifies How Night Temperatures Regulate the Healing Process of Oriental Melon Grafted onto Pumpkin.

Graft healing is a complex process affected by environmental factors, with temperature being one of the most important influencing factors. Here, oriental melon grafted onto pumpkin was used to study changes in graft union formation and sugar contents at the graft interface under night temperatures of 18 °C and 28 °C. Histological analysis suggested that callus formation occurred 3 days after grafting with a night temperature of 28 °C, which was one day earlier than with a night temperature of 18 °C. Vascular reconnection with a night temperature of 28 °C was established 2 days earlier than with a night temperature of 18 °C. Additionally, nine sugars were significantly enriched in the graft union, with the contents of sucrose, trehalose, raffinose, D-glucose, D-fructose, D-galactose, and inositol initially increasing but then decreasing. Furthermore, we also found that exogenous glucose and fructose application promotes vascular reconnection. However, exogenous sucrose application did not promote vascular reconnection. Taken together, our results reveal that elevated temperatures improve the process of graft union formation through increasing the contents of sugars. This study provides information to develop strategies for improving grafting efficiency under low temperatures.

Phenotyping xylem connections in grafted plants using X-ray micro-computed tomography.

Plants are able to naturally graft or inosculate their trunks, branches and roots together, this mechanism is used by humans to graft together different genotypes for a range of purposes. Grafts are considered successful if functional vascular connections between the two genotypes occur. Various techniques can evaluate xylem connections across the graft interface. However, these methods are generally unable to assess the heterogeneity and three-dimensional (3D) structure of xylem vessel connections. Here we present the use of X-ray micro-computed tomography to characterize the 3D morphology of grafts of grapevine. We show that xylem vessels form between the two plants of natural root and human-made stem grafts. The main novelty of this methodology is that we were able to visualize the 3D network of functional xylem vessels connecting the scion and rootstock in human-made stem grafts thanks to the addition of a contrast agent to the roots and improved image analysis pipelines. In addition, we reveal the presence of extensive diagonal xylem connections between the main axial xylem vessels in 2-year old grapevine stems. In conclusion, we present a method that has the potential to provide new insights into the structure and function of xylem vessels in largetissue samples.

Tissue-specific stilbene accumulation is an early response to wounding/grafting as revealed by using spatial and temporal metabolomics.

Grafting is widely used in horticulture. Shortly after grafting, callus tissues appear at the graft interface and the vascular tissues of the scion and rootstock connect. The graft interface contains a complex mix of tissues, we hypothesised that each tissue has its own metabolic response to wounding/grafting and accumulates different metabolites at different rates. We made intact and wounded cuttings and grafts of grapevine, and then measured changes in bulk flavonoid, phenolic acid and stilbenoid concentration and used metabolite imaging to study tissue-specific responses. We show that some metabolites rapidly accumulate in specific tissues after grafting, for example, stilbene monomers accumulate in necrotic tissues surrounding mature xylem vessels. Whereas other metabolites, such as complex stilbenes, accumulate in the same tissues at later stages. We also observe that other metabolites accumulate in the newly formed callus tissue and identify genotype-specific responses. In addition, exogenous resveratrol application did not modify grafting success rate, potentially suggesting that the accumulation of resveratrol at the graft interface is not linked to graft union formation. The increasing concentration of complex stilbenes often occurs in response to plant stresses (via unknown mechanisms), and potentially increases antioxidant activity and antifungal capacities.

P77: Improvements in the cuff and graft interface of a rotary Total Artificial Heart

Purpose: To evaluate design improvements of the inlet cuff-port and outlet graft-port interface of a Total Artificial Heart (TAH) on pannus formation. The orifice size, interface, blood flow path geometry, blood flow velocity, materials, surface finish, and hematologic parameters (such as anti-coagulants and anti-platelets) all contribute to the hemocompatibility of the TAH inflow and outflow. The focus of this work is the blood flow path geometry and material change. Methods: The performance of progressive inflow and outflow design iterations of a rotary total artificial heart operated in continuous and pulsatile outflow were evaluated in Corrient calves for durations of 30-90 days. Design modifications included a smoother blood flow port transition, geometrical improvements to the diameter and tangent angle to the polyurethane connector/pump interface, and methods of securing the connection including a titanium ring on the cuff with biospan rings and PEEK zip ties on both the cuffs and grafts. The graft flow path includes a circumferential hump which allows the titanium outflow port to seat against this hump and eliminate a void which could be a source of thrombus or emboli. Additionally, the cuff and port materials were changed. Subjects were 6-12 month old calves with weights ranging from 82 kg to 108 kg, while conditions such as pump flow, pressures and anticoagulants were closely monitored. The TAH was run in pulsatile mode for the majority of the studies. At necropsy, photos of the cuff and graft interface to the pump were analyzed and any tissue samples were sent for histological evaluation. Results: A titanium ring on the cuff prevented the cuff from pulling away from the titanium port at the ostium and also prevented the cuff from being to be pulled too far onto the port during surgery. Pannus formation at the interface of the cuff and graft to the titanium ports was graded from Absent (0) to Extreme (5), (Extreme equals >75% area reduction). In earlier design iterations, pannus formation at the inflow cuff or outflow graft interface ranged from (2) mild to (5) extreme. After implementing the design improvements, pannus was (0) absent in all inflow cuff interfaces. One graft that was not fully installed on the port had moderate buildup and the remainder had (0) absent to (1) minor at the outflow graft interface despite minimal anticoagulation. Conclusion: Improvements to the inflow cuff/outflow graft-port interface significantly reduced pannus and thrombus formation in chronic animal implants treated with limited anticoagulation.

Early detection of grapevine graft incompatibility: Insights into translocated and virus-induced incompatibility

In vineyards to control phylloxera (Daktulosphaira vitifolia Ficth) attacks in Vitis vinifera L., heterografted vines are planted using American vines hybrids as rootstocks. However, graft incompatibilities can affect grape yield and plant longevity. Thus, to identify early graft incompatibility factors, we established in vitro micrografting protocols coupled with histology and histochemistry analysis in grapevine graft combinations of known compatibility behavior. The histochemical characterization of the graft union revealed irregular cell arrangement, slower vascular differentiation, persistence of the necrotic layer, accumulation of starch, and lower differentiation of phloem cells in hetero- compared to homografts, indicating the presence of translocated incompatibility symptoms. We highlight the utility of evaluating the graft interface cellular arrangement and starch content via calcofluor and I2KI staining, respectively, as allowed to identify the graft combinations with lower graft success. Wounded and grafted Syrah plantlets pointed out an impaired sucrose distribution in these plants and levels of Grapevine Rupestris Stem Pitting associated Virus (GRSPaV) infections correlated with graft (un)-success in two Syrah clones micrografted onto 110-Ritcher rootstock. Furthermore, silencing GRSPaV before grafting increased graft success rates. We propose that grapevine graft incompatibility is mainly a virus-induced phenomenon that can arise even in certified plants.

Targeting Ultrastructural Events at the Graft Interface of Arabidopsis thaliana by A Correlative Light Electron Microscopy Approach.

Combining two different plants together through grafting is one of the oldest horticultural techniques. In order to survive, both partners must communicate via the formation of de novo connections between the scion and the rootstock. Despite the importance of grafting, the ultrastructural processes occurring at the graft interface remain elusive due to the difficulty of locating the exact interface at the ultrastructural level. To date, only studies with interfamily grafts showing enough ultrastructural differences were able to reliably localize the grafting interface at the ultrastructural level under electron microscopy. Thanks to the implementation of correlative light electron microscopy (CLEM) approaches where the grafted partners were tagged with fluorescent proteins of different colors, the graft interface was successfully and reliably targeted. Here, we describe a protocol for CLEM for the model plant Arabidopsis thaliana , which unambiguously targets the graft interface at the ultrastructural level. Moreover, this protocol is compatible with immunolocalization and electron tomography acquisition to achieve a three-dimensional view of the ultrastructural events of interest in plant tissues. Graphical abstract.

Study of the grafting compatibility of the apple rootstock 12–2, resistant to apple replant diseases (ARD)

BackgroundCultivation of resistant rootstocks can effectively prevent apple replant disease (ARD), and grafting tests are an important means of evaluating the compatibility of rootstocks with scions.MethodsThe apple rootstocks 12–2 (self-named) and Malus hupehensis Rehd. (PYTC) were planted in a replanted 20-year-old apple orchard. The two rootstocks were grafted with scions of 13 apple varieties. Multiple aboveground physiological parameters of the grafted combinations were measured and evaluated to verify the grafting affinity of 12–2 with the scions as compared to Malus hupehensis Rehd. (PYTC).ResultsThe graft survival rate and graft interface healing of 12–2 did not differ significantly from those of PYTC. Mechanical strength tests of the grafted interfaces showed that some mechanical strength indices of Redchief, Jonagold, Starking, Goldspur and Yinv apple varieties were significantly higher when they were grafted onto 12–2 compared to the PYTC control. The height and diameter of shoots and the relative chlorophyll content, photosynthetic and fluorescence parameters, antioxidant enzyme activities and malondialdehyde content of leaves showed that Fuji 2001, Tengmu No.1, RedChief, Gala, USA8, and Shoufu1 grew similarly on the two rootstocks, but Tianhong 2, Lvguang, Jonagold, Starking, Goldspur, Yinv and Luli grew better when grafted onto 12–2 than onto the PYTC control. The rootstock 12-2, therefore, showed good grafting affinity.ConclusionThese results provide experimental materials and theoretical guidance for the cultivation of a new grafting compatible rootstock to the 13 studied apple cultivars.

The emergence of spiraling tracheary element bundles in incompatible grafts.

In distantly-related plant grafting, incompatibility often occurs between scion and rootstock, resulting in growth stagnation, and eventually graft failure. In this study, we found that an emergent structure, or the spiraling tracheary element (TE) bundles consisting of TE masses occurring at the graft interface, was extensively present in the highly incompatible interfamilial graft of Brassica napus/Portulaca oleracea (Bn/Po) and Nicotiana benthamiana/Portulaca oleracea (Nb/Po). This special structure mostly appeared in the local area near the grafting union, and the frequency and quantity of the spiraling tracheary element bundles were much higher in the scion than in the rootstock. Nevertheless, only a small portion of Arabidopsis thaliana/Portulaca oleracea (At/Po) interfamilial grafts showed a less spiraled TEs at the grafting union (usually a circular TE), which is consistent with its growth performance. This study consolidated that spiraling TE bundles were an important indicator for graft incompatibility. The possible reason for the formation of spiraling TE bundles in interfamilial grafts was discussed.

Biomechanical comparison between various screw fixation angles for Latarjet procedure: a cadaveric biomechanical study.

The Latarjet procedure is a reliable treatment for the management of anterior glenohumeral instability with glenoid bone loss. However, the biomechanical properties of different fixation angles between screw and glenoid surface (α angle) have rarely been studied. The aim of the study was to investigate and compare the fixation stability, failure load, and failure mechanism between different α angles for Latarjet procedures, which were performed on cadaver specimens. Twenty-four shoulder specimens (8 in each of 3 groups) were dissected free of all soft tissue, and a 25% glenoid defect was created. The coracoid process was osteomized and fixed with 2 screws at 3 different α angles: 0° (group A), 15° (group B), and 30° (group C). Specimens were mounted to a testing apparatus, and cyclic loading (100 cycles at 1Hz) was applied with a staircase protocol (50, 100, 150, and 200N). Gross graft displacement and interface displacement were measured. The ultimate failure loads and failure mechanisms were recorded. There was no significant difference in gross displacement under any cyclic load between 3 groups. However, a significant larger interface displacement was noted in group C than in group A in 150-N cyclic loading (P=.017). Under failure strength testing, all 24 specimens failed because of screw cutout from the glenoid, and the ultimate failure load was similar among the three groups. Compared with the 0° α angle, the displacement after cyclic loading did not significantly increase when the α angle was increased to 15° but significantly increased at 30° for Latarjet procedures, which were performed on cadaver specimens. The results suggest that surgeons should apply the screws as parallel as possible to the glenoid surface when performing the Latarjet procedure. Although mild deviation may not reduce fixation stability, α angles greater than 30° should be avoided.

Micrographic View of Graft Union Formation Between Watermelon Scion and Squash Rootstock.

Grafting has become a common practice for watermelon [Citrullus lanatus (Thunb.) Matsum & Nakai] production in many parts of the world, due to its efficacy against biotic and abiotic stressors. However, grafting success for watermelon is challenging in part due to the complex anatomy of the cucurbit vascular system. The survival of grafted transplants depends on compatibility between the scion and rootstock, which in turn depends on anatomical, physiological, and genetic variables. A better understanding of cucurbit anatomy and graft union formation would inform grafting approaches and transplant management. An anatomical study was conducted by scanning electron microscopy (SEM) at 11 and 25 days after grafting (DAG) with seedless watermelon cultivar ‘Secretariat’ grafted onto compatible rootstock cultivars ‘Pelop’ (Lagenaria siceraria) and ‘Tetsukabuto’ (Cucurbita maxima × Cucurbita moschata) in comparison to non-grafted watermelon and rootstock seedlings. At 11 DAG, the parenchymatic cells of the central pith of grafted plants were dead and a necrotic layer was observed, representing the beginning of callus formation. New xylem strands were formed in the vascular system, connecting the rootstock with the scion. At 25 DAG, fully developed vascular bundles at the graft interface were observed with both scion-rootstock combinations. Although more studies are necessary to characterize the sequence of physiological events after grafting in Cucurbit species, this is one of the first studies to describe the complex anatomical changes that occur during watermelon graft healing.

The dynamic changes of tracheary elements in an intraspecific quinoa (Chenopodium quinoa) graft

Vascular connection is key to successful graft. Little study has been devoted to the behavior of tracheary elements (TEs), the basic component of vascular bundles, during vascular connection between scion and rootstock. Here we report the structural changes of TEs at the graft interface between two quinoa cultivars, Qaidam White-1 (QW1) and Qaidam Red-1 (QR1). Our results showed that TEs in ungrafted plants developed following an ontogenetic sequence, i.e., the annular vessel, helical vessel, scalariform vessel, reticulate vessel, and pitted vessel. However, this process was greatly accelerated in grafted plants, resulting in quick developmental transition of TE wall patterning. At the early stage of intraspecific grafting (e.g., 5 days after grafting), the membrane-like cellular patches were heavily accumulated at the graft interface but quickly retreated within 2–4 days, suggesting an early emergency response to grafting. The TE length in both scion and rootstock was significantly shorter (more than 50% on average, nTE = 747) than the ungrafted plants in the same period. These short TEs were gradually integrated into a long, continuous conduit, thereby enabling the functional vasculature at the graft union. In addition, the pit size was gradually reduced, for example, for the surface area of outer pit aperture, from 12.73 ± 3.15 to 5.40 ± 0.30 μm2, or for the surface area of inner pit aperture, from 9.34 ± 3.33 to 1.96 ± 1.04 μm2, in 18 days (npits = 2830). Taken together, the morphological changes of TEs and cellular responses to grafting in the intraspecific grafts seemed to be conservative to other homografts and heterografts, implying that these behavioral changes are highly adaptive to the scion–rootstock interaction.

Making a connection: cell-cell communication at the graft interface.

Making a connection: cell-cell communication at the graft interface.

Identifying early metabolite markers of successful graft union formation in grapevine.

Grafting is an important horticultural technique used for many crop species. However, some scion/rootstock combinations are considered as incompatible due to poor graft union formation and subsequently high plant mortality. The early identification of graft incompatibility could allow the selection of non-viable plants before planting and would have a beneficial impact on research and development in the nursery sector. In general, visible phenotypes of grafted plants (size, root number, etc.) are poorly correlated with grafting success, but some studies have suggested that some polyphenols could be used as markers of graft incompatibility several months or years after grafting. However, much of the previous studies into metabolite markers of grafting success have not included all the controls necessary to unequivocally validate the markers proposed. In this study, we quantified 73 primary and secondary metabolites in nine hetero-grafts and six homo-grafted controls 33 days after grafting at the graft interface and in both the scion and rootstock woody tissues. Certain biomarker metabolites typical of a high stress status (such as proline, GABA and pallidol) were particularly accumulated at the graft interface of the incompatible scion/rootstock combination. We then used correlation analysis and generalized linear models to identify potential metabolite markers of grafting success measured one year after grafting. Here we present the first attempt to quantitatively predict graft compatibility and identify marker metabolites (especially asparagine, trans-resveratrol, trans-piceatannol and α-viniferin) 33 days after grafting, which was found to be particularly informative for homo-graft combinations.

Incorporation of Whipstitch Suture in Tibial Interference Fixation Improves Pullout in Anterior Cruciate Ligament Soft Tissue Grafts.

Interference screw fixation of soft tissue grafts is commonly used in anterior cruciate ligament (ACL) reconstruction. The purpose of this study was to determine whether including suture material at the graft-screw interface affects ultimate fixation strength of soft tissue grafts using a tibialis anterior tendon allograft model. Forty fresh-frozen human tibialis anterior tendon allografts were fixed to rigid polyurethane foam simulating the tibial tunnel. Twenty grafts underwent fixation with interference screws and 20 with interference bolts. Within each group, 10 grafts had suture in contact with either the screw or bolt. A load-to-failure test was then performed at a rate of 200 mm/min. The group of allografts with sutures in the tibial tunnel had significantly higher load to failure than the group without sutures. Using interference screw fixation, failure load of the grafts without sutures in the tunnel (535.2 ± 73.40 N) was significantly lower (P = .001) than with sutures in the tunnel (696.3 ± 110.0 N). Using interference bolt fixation, failure load of the grafts without sutures in the tunnel (613.0 ± 83.46 N) was significantly lower (P <.0001) than with sutures in the tunnel (845.8 ± 87.23 N). In a biomechanical model, suture within the tibial tunnel enhances fixation strength with both interference screw and bolt fixation for soft tissue tibialis anterior allografts. Additionally, there was no difference in load to failure when comparing failure of a screw with suture in the tunnel with an interference bolt without suture. Due to improved biomechanical properties, incorporation of suture in the bone-graft interface should be considered when performing soft tissue ACL allograft reconstructions. Failure at the tibial bone-graft interface is a known complication of ACL reconstruction, and incorporation of suture within the interface should be considered for improved biomechanical properties.

Clinical and Radiological Outcomes of Autologous Osteochondral Transplantation with and without Micronized Allograft Cartilage Matrix Augmentation for Osteochondral Lesions of the Talus

Category:Ankle; Basic Sciences/Biologics; TraumaIntroduction/Purpose:Autologous osteochondral transplantation (AOT) using a cylindrical graft, in the treatment of osteochondral lesions of the talus (OLT) is typically indicated for patients with larger lesions. However, with lesions that are irregular in shape, the AOT graft may not completely replace the lesion. For these lesions, we utilize Extracellular Matrix Cartilage Allograft (EMCA) augmentation in AOT to act as a physiologic grout between the host and graft interface. The purpose of this study was to evaluate the clinical and radiological outcomes of AOT with concentrated bone marrow aspirate (CBMA) and EMCA augmentation in the treatment of OLT.Methods:A retrospective analysis comparing patients treated with AOT/CBMA alone and AOT with CBMA/EMCA was performed. Clinical outcomes were evaluated with the use of the Foot and Ankle Outcome Score (FAOS). Magnetic resonance imaging (MRI) was evaluated with the use of the Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score. Cyst formation was also evaluated on postoperative MRI.Results:Twenty-six patients were included in the AOT + CBMA/EMCA group, with 10 males and 16 females. Thirty-four patients were included in the AOT/CBMA group, with 17 males and 17 females. The mean symptoms, pain, ADL, sports activities, and QOL scores in FAOS significantly improved in both groups (p<0.001), but there was no significant difference between groups at final follow-up. There was no significant difference between the mean MOCART scores between groups (p=0.118). In the AOT/CBMA group, 2 patients (7.7%) complained of knee pain and 5 patients (19.2%) required additional surgery (2 hardware removals and 3 arthroscopic debridements of scar tissue in the ankle). In the AOT + CBMA/EMCA group, 3 patients (8.8%) complained of knee pain, and one patient (2.9%) required hardware removal.Conclusion:The current study demonstrated that AOT combined with CBMA and EMCA was an effective surgical treatment for OLT, providing good clinical and radiological outcomes. However, the benefit of combining ECMA with CBMA in small chondral defects at the host graft interface may be marginal as the biologic effect is induced by the CBMA and the mechanical scaffold effect of ECMA may not be required in such small defects.

A correlative light electron microscopy approach reveals plasmodesmata ultrastructure at the graft interface.

Despite recent progress in our understanding of graft union formation, we still know little about the cellular events underlying the grafting process. This is partially due to the difficulty of reliably targeting the graft interface in electron microscopy to study its ultrastructure and three-dimensional architecture. To overcome this technological bottleneck, we developed a correlative light electron microscopy (CLEM) approach to study the graft interface with high ultrastructural resolution. Grafting hypocotyls of Arabidopsis thaliana lines expressing yellow FP or monomeric red FP in the endoplasmic reticulum (ER) allowed efficient targeting of the grafting interface for examination under light and electron microscopy. To explore the potential of our method to study sub-cellular events at the graft interface, we focused on the formation of secondary plasmodesmata (PD) between the grafted partners. We showed that four classes of PD were formed at the interface and that PD introgression into the cell wall was initiated equally by both partners. Moreover, the success of PD formation appeared not systematic with a third of PD not spanning the cell wall entirely. Characterizing the ultrastructural characteristics of these incomplete PD gives us insights into the process of secondary PD biogenesis. We found that the establishment of successful symplastic connections between the scion and rootstock occurred predominantly in the presence of thin cell walls and ER-plasma membrane tethering. The resolution reached in this work shows that our CLEM method advances the study of biological processes requiring the combination of light and electron microscopy.

Cell-to-Cell Connection in Plant Grafting-Molecular Insights into Symplasmic Reconstruction.

Grafting is a means to connect tissues from two individual plants and grow a single chimeric plant through the establishment of both apoplasmic and symplasmic connections. Recent molecular studies using RNA-sequencing data have provided genetic information on the processes involved in tissue reunion, including wound response, cell division, cell-cell adhesion, cell differentiation and vascular formation. Thus, studies on grafting increase our understanding of various aspects of plant biology. Grafting has also been used to study systemic signaling and transport of micromolecules and macromolecules in the plant body. Given that graft viability and molecular transport across graft junctions largely depend on vascular formation, a major focus in grafting biology has been the mechanism of vascular development. In addition, it has been thought that symplasmic connections via plasmodesmata are fundamentally important to share cellular information among newly proliferated cells at the graft interface and to accomplish tissue differentiation correctly. Therefore, this review focuses on plasmodesmata formation during grafting. We take advantage of interfamily grafts for unambiguous identification of the graft interface and summarize morphological aspects of de novo formation of plasmodesmata. Important molecular events are addressed by re-examining the time-course transcriptome of interfamily grafts, from which we recently identified the cell-cell adhesion mechanism. Plasmodesmata-associated genes upregulated during graft healing that may provide a link to symplasm establishment are described. We also discuss future research directions.

Effect of Schwann cell transplantation combined with electroacupuncture on axonal regeneration and remyelination in rats with spinal cord injury.

Axonal impairment and demyelination after compressed spinal cord injury lead to serious neurological dysfunction. Increasing studies have suggested that Schwann cells (SCs) transplantation is a reliable, effective, and promising method for treating spinal cord injury. However, single SCs transplantation is insufficient to promote the full recovery of neurological function. Additional approaches are required to support SCs transplantation as a treatment for spinal cord injury. In the study, we investigated whether the combination of electroacupuncture (EA) and SCs transplantation was a reliable intervention for spinal cord injury. We found that rats in the combination group had significantly higher functional locomotor scores than those received single treatment. By immunostaining, we found EA can not only improve survival and proliferation of transplanted SCs but also inhibit SC apoptosis and block the formation of an astrocytic scar. Additionally, EA promoted regenerated axons extending "bullet-shaped" growth cones into the lesion. Remarkably, EA can modify astrogliosis to promote axonal regeneration following SCs transplantation through inducing extension of astrocytic processes in the SCs graft interface. More importantly, the combination of SCs engraftment and EA can enhance corticospinal-tract axonal regeneration and remyelination after spinal cord injury through up-regulating neuregulin 1 type III in SCs and its downstream signaling mediators. Thus, it is concluded that SCs effectively promote axonal recovery after spinal cord injury when combined with EA stimulation. The experimental results have reinforced the theoretical basis of EA for its clinical efficacy in patients with spinal cord injury and merited further investigation for potential clinical application.

Physiological and Molecular Characterization of New Apricot Cultivars Grafted on Different Prunus Rootstocks

In the last years, an important renewal of plant material from different breeding programs is taking place in apricot in order to improve resistance to biotic stresses, extension of the harvest season, fruit quality, and productivity. However, the graft compatibility of many of these cultivars with most popular Prunus rootstocks is unknown, and this is an essential agronomical trait for their better performance and longevity. Hence, the introduction of new cultivars requires knowledge of the extent and nature of incompatibility reactions before releasing these cultivars on the market. In this study, the determination of graft compatibility was carried out in 13 new apricot cultivars grafted on four Prunus rootstocks: ‘Marianna2624’ (P. cerasifera × P. musoniana), ‘Miragreen’ (P. cerasifera × P. davidiana), ‘Mirared’ (P. cerasifera × Nemared), and ‘Montclar’ (P. persica L. seedlings) at early stages of development. By combining cytomorphological, anatomical, and phenylalanine ammonia-lyase (PAL) gene expression analysis at the graft interface, as well as different vegetative parameters, the results highlighted ‘Miragreen’ and ‘Mirared’ as promising rootstocks for apricot, showing the highest degree of compatibility with more than 90% of the apricot cultivars. These results provide useful information for breeders and growers by selecting the most suitable scion-rootstock for efficient orchard design by planting compatible graft combinations.