The potential prophylactic and therapeutic impacts of niacin on ischemia/reperfusion injury of testis.

INTRODUCTION: The testicular ischemia-reperfusion (I/R) injury is characterized by the excessive aggregation of un-scavenged reactive oxygen species, leading to the heightened levels of oxidative stress. This phenomenon plays a pivotal role in the pathophysiology of testicular torsion damage. OBJECTIVE: The current study aimed to detect the prophylactic and therapeutic effects of niacin on testicular I/R injury. STUDY DESIGN: Twenty-four healthy adult male Sprague Dawley rats were randomly allocated into three groups as follows: (1) sham group, (2) torsion/detorsion (T/D) group, and (3) treatment group which received 200 mg/kg niacin along with testicular T/D. Torsion/detorsion was induced by 2 h of torsion followed by 10 days of reperfusion period. In the treatment group, niacin was injected 30 min before the reperfusion period intraperitoneally and continued for 10 days by oral gavage. RESULTS: T/D was associated with marked decreases in terms of sperm count, viability, and kinematic parameters versus the sham group (P < 0.05), which niacin significantly reverted the kinematic parameters (P < 0.05). I/R injury caused a significant increase in the number of abnormal epididymal sperms compared to the sham group (P < 0.05). Niacin decreased the epididymal sperm abnormality significantly compared to the T/D group (P < 0.05). Tissue abnormalities in T/D group, such as edema, hyperemia, inflammation, and necrosis were completely visible histopathologically, while the histological changes in the niacin-treated group were better than those in the T/D group. Regarding the pathological parametric evaluations, I/R injury significantly reduced the mean testicular biopsy score (MTBS), germinal epithelial cell thickness (GECT), and mean seminiferous tubular diameter (MSTD), and increased the tubular hypoplasia/atrophy (THA) compared to the sham group (P < 0.05), which niacin treatment significantly improved the MTBS and GECT compared to the T/D group (P < 0.05). T/D significantly increased the oxidative stress index (OSI) and lipid peroxidation (MDA) (P < 0.05). Niacin significantly reduced the OSI and MDA levels compared to the T/D group (P < 0.05). DISCUSSION: The current study found that niacin has preventive/therapeutic effects against the elevation of oxidative stress markers and depletion of antioxidants during I/R injury. Following administration of niacin, a reduction in histologic injury was observed in rats. In our study, we showed the antioxidant properties of niacin and its capacity to protect against I/R damage. CONCLUSION: The findings of the present investigation revealed that niacin, as an antioxidant agent, can suppress the oxidative stress induced by testicular I/R injury, and can be used as a supplementary agent in the treatment of those undergoing testicular torsion surgery.

Comparing the healing properties of intra-articular injection of human dental pulp stem cells and cell-free-secretome on induced knee osteoarthritis in male rats.

OBJECTIVE: Osteoarthritis (OA) is a common and painful joint disease with multifactorial causes. Stem cells, due to their high ability to reproduce and differentiate, have created a new horizon in tissue engineering of cartilage and bone. Secretions are one of the new therapies that can be used with stem cells or separately. This study aimed to compare the healing effects of human dental pulp stem cells, cell-free secretome, and human dental pulp mesenchymal stem cells with secretome in the induced OA in male rats. METHODS: Dental pulp mesenchymal stem cells were isolated and prepared from human dental pulp. The collagenase type II was injected into the knee of twenty-five male Sprague-Dawley rats, and after 10 weeks, OA was confirmed. Rats were divided into five groups (n = 5): 1) Human dental pulp stem cells plus secretome (HDP+Sec); 2) Human dental pulp stem cells (HDP); 3) Secretome (Sec); 4) Hyalgan as the positive control (Hya); 5) No treatment as the negative control (Ctrl). After 12 weeks since OA was confirmed, the healing process was examined by histopathology and radiology evaluations. RESULTS: Histopathological evaluations, radiological assessments, and matrix indexes in three treatment groups significantly improved compared to the Ctrl and Hya groups. Surface in HDP+Sec was significantly better than the Ctrl group. In radiological evaluations, a significant decrease in OA was observed in the three treatment groups in comparison with the Ctrl groups. There was no significant difference between the treatment groups in any radiological and histopathological evaluations. HDP + Sec group slightly records better results compared to Sec or HDP treatment groups. CONCLUSION: It was concluded that human dental pulp stem cells and their secretome promote cartilage regeneration due to their cell protective potential as well as matrix degeneration reduction capacity.

The healing effects of thymoquinone on experimentally induced traumatic tendinopathy in rabbits.

OBJECTIVES: Thymoquinone is a major bioactive compound present in the black seeds of the Nigella sativa. Tendon injuries are almost 50% of all musculoskeletal injuries. The recovery of tendon after surgery has become a significant challenge in orthopedics. DESIGN: The purpose of this study was to investigate the healing effect of thymoquinone injections in 40 New Zealand rabbits tendon traumatic models. MATERIALS AND METHODS: Tendinopathy was induced by trauma using surgical forceps on the Achilles tendon. Animals were randomly divided into 4 groups: (1) normal saline injection (control), (2) DMSO injection, (3) thymoquinone 5% w/w injection, and (4) thymoquinone 10% w/w injection. Forty-two days after surgery, biochemical and histopathological evaluations were done, and biomechanical evaluation was conducted 70 days after surgery. RESULTS: Breakpoint and yield points in treatment groups were significantly higher compared to control and DMSO groups. Hydroxyproline content in the 10% thymoquinone receiving group was higher than all groups. Edema and hemorrhage in the histopathological evaluation were significantly lower in the thymoquinone 10% and thymoquinone 5% receiving groups compared to control and DMSO groups. Collagen fibers, collagen fibers with fibrocytes, and collagen fibers with fibroblasts were significantly higher in the thymoquinone 10% and thymoquinone 5% receiving groups compared to control groups. CONCLUSIONS: Thymoquinone injection in the tendon in the concentration of 10% w/w is a simple and low-cost healing agent that could enhance mechanical and collagen synthesis in traumatic tendinopathy models in rabbit.

Surgical management of an aspirated bone in a Shih Tzu terrier dog: a case report.

Foreign bodies in the respiratory tract (trachea/bronchus) are very rare conditions; therefore, it is not on top of the list of differential diagnoses in patients with chronic or severe cough, but its occurrence should not be considered unexpected. A 2-year-old male Shih Tzu terrier mix dog (9.20 kg) with a history of dyspnea for 6 days was referred to the Veterinary Teaching Hospital of Shiraz University, Shiraz, Iran. In the clinical examination, respiratory distress and pain during palpation of the neck area were observed. Radiology indicated a triangular radiopaque object (bone) in the trachea of the animal. The size of the foreign body, the weakness of the grasping forceps of the device, and the edges of the bone being stuck in the trachea caused tracheoscopy failure after 30 min of trying. Surgical procedure (tracheotomy) was effective to remove the foreign body using Noyes alligator tissue forceps. Aspirated foreign body is not a common condition. In the case of early recognition and immediate treatment of the aspirated foreign body, the prognosis is usually good.

Wound healing effect of Carum carvi L. on the incised skin wound in male rats: Histopathology, total protein and biomechanical evaluations.

BACKGROUND: The skin has several functions, one of the most important of which is to protect the internal organs from external damage and the entry of germs. Since skin and wound healing is one of the mostly concerned issues worldwide, the development of wound healing remedies is one of the main fields in modern medical research. OBJECTIVES: To evaluate the effect of the hydroalcoholic extract of Cumin carvi L. seed as one of the traditional medicinal plants used for wound healing through an in vivo model. METHODS: Wide circular skin wounds (2 × 2 cm) were created on the dorsal area of 50 Sprague-Dawley male rats ​​following ethical principles. The animals were divided into five groups including no treatment, base gel, tetracycline treatment, 10% v/v hydroalcoholic extract of Cumin carvi L. seed treatment and 20% v/v hydroalcoholic extract of Cumin carvi L. seed treatment group. Treatment was performed within 20 days. On days 1, 3, 5, 7 and 10, photographs were taken, and the percentage of wound healing was calculated. Also, on the 10th day, the skin area was sampled for histopathology and on the 20th day, the skin was sampled for biomechanical and total protein assessments. RESULTS: The results of wound healing percentage showed that from day 3 onwards, there was a significant improvement between the group treated with 20% v/v hydroalcoholic extract of Cumin carvi L. and the negative control and basal gel groups (p < 0.05). According to histopathological and total protein content evaluations, the amount of collagen production and inflammation score in the Cumin carvi-treated groups confirmed the healing process compared to other groups. CONCLUSIONS: According to the results of this project, 20% v/v ethanolic extract of Cumin carvi L. has potential therapeutic effects in the treatment of skin wounds. Wounds are one of the health concerns, and the economic burden of wound care and healing has continued to increase over the past years.  The healing effects of C. carvi. ethanolic extract on the wound were investigated. The histopathological and macroscopical evaluations, as well as total protein content, were measured to investigate its wound healing properties.

The evaluation of citral effects on experimental unilateral testicular ischemia/reperfusion injury.

This investigation aimed to evaluate the defensive impacts of citral on ischemia/reperfusion (I/R) injury induced by testicular torsion/detorsion (T/D) in rats in an experimental model. The grouping of subjects was as follows: (1) sham, (2) T/D, (3) and (4) T/D plus citral 150 and 300 mg/kg, respectively, and (5) intact (citral 300 mg/kg). T/D was performed by testicular 720° turning for 2 h and then detorsion for 24 h. Blood serum was obtained to assess testosterone and oxidative stress markers, epididymal sperms were collected for sperm staining and sperm analysis, and testicular tissues were examined for histopathology. T/D damage was associated with a remarkable decline in sperm total count, viability, and some velocity parameters in comparison to the sham group (p < 0.05), which could be reversed significantly by citral (p < 0.05). Histopathologically, T/D damage caused severe oedema, haemorrhage, inflammation, and seminiferous tubules disruption, while citral improved significantly the mean seminiferous tubular diameter, Cosentino's score, and Johnsen's score (p < 0.05). I/R injury was associated with significant increased malondialdehyde and oxidative stress index, and also significant reduced total antioxidant capacity and testosterone versus the sham group (p < 0.05), which all were prevented significantly by citral administration (p < 0.05). The outcomes greatly proved that testicular I/R injury could be significantly prevented by citral.

Effects of Combination of BMP7, PFG, and Autograft on Healing of the Experimental Critical Radial Bone Defect by Induced Membrane (Masquelet) Technique in Rabbit.

BACKGROUND: Healing of large segmental bone defects can be challenging for orthopedic surgeons. This research was conducted to provide further insight into the effects of BMP7 in combination with autograft and platelet fibrin glue (PFG) on bone regeneration by Masquelet technique (MT). METHODS: Twenty five domestic male rabbits, more than 6 months old, weighing 2.00±0.25 kg were randomly divided into five equal groups as follows: MT-blank cavity (without any biological or synthetic materials) (1), blank cavity (2), MT-autograft (3), MT-autograft-BMP7 (4), and MT-BMP7-PFG (5). A 20 mm segmental defect was made in radial bone in both forelimbs. The Masquelet technique was done in all groups except group 2. The study was evaluated by radiology, biomechanics, histopathology and scanning electron microscopy. RESULTS: The results showed that Masquelet technique enhanced the healing process, as, the structural and functional criteria of the injured bone showed significantly improved bone healing (P<0.05). Treatment by PFG-BMP7, Autograft-BMP7, and autograft demonstrated beneficial effects on bone healing. However, Autograft-BMP7 was more effective than autograft in healing of the radial defect in rabbits. CONCLUSION: Our findings introduce the osteogenic materials in combination with Masquelet technique as an alternative for reconstruction of the big diaphyseal defects in the long bones in animal models. Our findings may be useful for clinical application in future.

Protective effects of crocin on testicular torsion/detorsion in rats.

Oxidative stress, caused by extreme accumulation of un-scavenged reactive oxygen species, plays an integral role in the Ischemia-Reperfusion (I/R) injury to the testicles following testicular torsion. The current research aimed to examine the protective effects of crocin as a natural antioxidant on testicular I/R injury in rats. Animals were divided randomly into five groups (seven each): (1) sham group, (2) torsion/detorsion (T/D) group, (3) intact group with 100 mg/kg crocin, (4) and (5) T/D groups followed by treatment with two different doses of crocin (50 and 100 mg/kg (IP)). I/R injury was induced by 720° clockwise torsion of the left testicles for 2 h. After 24 h of reperfusion, blood samples and epididymal sperms were collected to measure biochemical (GPx, SOD, and MDA), hormonal (testosterone), and sperm parameters (total sperm recovery, motility, viability, and morphology). Moreover, affected testicles were subjected to histopathology examination. I/R injury caused a significant reduction in sperm characteristics (except for morphology) (P < 0.05), which could not be significantly improved by crocin administration at either dose (P > 0.05). Johnsen's testicular score, mean seminiferous tubular diameter, and germinal epithelial cell thickness were significantly decreased in the T/D group compared to the intact and sham groups. However, crocin could significantly improve the histopathological parameters in both treatment groups compared to the T/D group (P < 0.05). T/D reduced SOD and GPx activity and testosterone level significantly (except for GPx) compared to the sham group (P < 0.05). However, crocin administration could significantly reverse them. Also, crocin reduced the amount of MDA significantly in the high-dose treatment group in comparison to T/D group (P < 0.05). The results of the current study revealed that crocin could be a promising agent to protect against I/R injury following surgical correction of the testicular torsion.

Propolis extract a new reinforcement material in improving bone healing: An in vivo study.

BACKGROUND: Propolis is known for its antioxidant, immune response modulating, and wound healing effects. In the present study in order to determine the bone healing capacity of the propolis extract, a critical sized, nonunion, radial bone defect model was repaired in rat, using chitosan and demineralized bone matrix (DBM) scaffolds along with propolis extract. MATERIALS AND METHODS: Seventy-two radial bone defects in 36 healthy male rats were randomly divided into 6 groups (n = 12/group). The groups included autograft, defect or untreated group, chitosan, DBM, chitosan and propolis (chitosan-propolis), and DBM and propolis (DBM-propolis). The bone repairing capability was characterized using radiography at 28th, 42nd and 56th postoperative days. Gross morphologic, histopathologic, histomorphometric and biomechanical examinations were performed following euthanasia at the 56th post-operative day. RESULTS: The DBM-propolis group, showed better structural and biomechanical properties compared to the untreated, DBM, chitosan and chitosan-propolis groups. The defect site in the chitosan and untreated groups were mainly restored by fibrous connective tissue while the lesions in the autograft group were mostly filled by cartilage and a lesser amount of woven bone. The woven bone, and the hyaline cartilage were the main constituents of the newly formed tissues in the DBM-propolis group, at the 56th day after injury. CONCLUSION: The results of this study showed that percutaneous injection of diluted aqueous propolis extract in the bone defect (25 mg/defect) can improve bone formation in the critical radial bone defect in rat. Since there was no significant difference between the autograft and DBM-propolis group, probably this therapeutic strategy has high potential in augmentation of autologous bone grafting.

The effects of gelatin, fibrin-platelet glue and their combination on healing of the experimental critical bone defect in a rat model: radiological, histological, scanning ultrastructural and biomechanical evaluation.

Fibrin-platelet glue (FPG) is a blood derivative, in which platelets and fibrinogen are concentrated in a small plasma volume, by differential centrifugation and precipitation. It can form a three-dimensional and biocompatible fibrin scaffold with a myriad of growth factors and proteins that are released progressively to the local environment and contribute to the accelerated postoperative bone healing. Gelatin (Gel) is a derivative of collagen and can promote cell adhesion and proliferation due to its unique sequence of amino acids, so it is suitable for bone tissue applications. This study examined the effects of Gel, FPG and their combinations as bone scaffold on the healing of surgically created critical-size defects in rat radius. Fifty critical size defects of 5 mm long were bilaterally created in the radial diaphysis of 25 rats. The animals were randomly divided into five equal groups as empty defect, autograft, Gel, FPG and Gel-FPG groups (n = 10 in each group). Radiographs of each forelimb were taken postoperatively on the 1st day and then at the 28th and 56th days post injury to evaluate bone formation, union and remodeling of the defect. After 56 days, the rats were euthanized and their harvested healing bone samples were evaluated by histopathology, scanning electron microscopy (SEM) and biomechanical testing. The results of present study showed that the Gel alone did not significantly affect bone healing and regeneration; however, the Gel treated defects promoted healing more than those that were left untreated (negative control). Furthermore, the FPG-enhanced grafts provided a good scaffold containing numerous growth factors for proliferation of osteoinduction and was effective in improving the structural and functional properties of the newly formed bone more than that of the untreated and also the Gel treated groups. Incorporation of Gel into the FPG scaffold improved healing potential of the FPG scaffold; however, it was still inferior to the autograft (positive control). Although the Gel-FPG scaffolds had best effectiveness during bone regeneration, it still needs to be further enhanced by incorporation of the ceramic and osteoinductive biomaterials.

Healing potential of nanohydroxyapatite, gelatin, and fibrin-platelet glue combination as tissue engineered scaffolds in radial bone defects of rats.

Different biomaterials have been used in orthopedic surgery. Evaluation of biomaterials for bone healing promotion has been a wide area of research of the orthopedic field. Sixty critical size defects of 5 mm long were bilaterally created in the radial diaphysis of 30 rats. The animals were randomly divided into six equal groups as empty defect, autograft, nanohydroxyapatite (nHA), Gelatin (Gel)-nHA, fibrin-platelet glue (FPG)-nHA, and Gel-FPG-nHA groups (n = 10 in each group). Radiographs of each forelimb were taken postoperatively on the 1st day and then at the 28th and 56th days post injury. After 56 days, the rats were euthanized and their harvested healing bone samples were evaluated by histopathology, scanning electron microscopy, and biomechanical testing. All the treated defects demonstrated significantly superior new bone formation, remodeling, and bone tissue volume. Moreover, the defects treated with FPG-nHA showed significantly higher ultimate load, yield load, and stiffness. The Gel-FPG-nHA moderately improved bone regeneration that was not close to the autograft in some parameters, whereas FPG-nHA significantly improved bone healing closely comparable with the autograft group in most parameters. In conclusion, although all the nHA-containing scaffolds had some beneficial effects on bone regeneration, the FPG-nHA scaffold was more effective in improving the structural and functional properties of the newly formed bone and was more osteoinductive than the Gel and was comparable to the autograft. Therefore, the FPG can be regarded as a promising option to be used in conjunction with mineral scaffolds for bone tissue engineering.

Chitosan/gelatin/platelet gel enriched by a combination of hydroxyapatite and beta-tricalcium phosphate in healing of a radial bone defect model in rat.

This study compared the regeneration potentials of the hydroxyapatite (HA) and beta-tricalcium phosphate (ß-TCP) alone or in combination with a HA:TCP ratio of 30:70 in the critical-sized radial bone defects of rats. Bilateral 60 radial bone defects created were randomly divided into six equal groups (n=10 defects/group) including autograft, untreated or defect, chitosan-gelatin-platelet gel (CGP), CGP-HA, CGP-TCP and CGP-HA/TCP. The defects were evaluated by radiography, morphology, histopathology, histomorphometry, CT scan, scanning electron microscopy and biomechanical testing after eight weeks. Compared with the untreated and CGP-HA groups, the CGP and CGP-HA/TCP groups showed significantly higher new bone formation, bone volume, and mechanical properties. The CGP-HA and CGP-TCP scaffolds showed low biodegradability, whereas the CGP scaffolds were completely degraded. Osteoconductivity and osteoinductivity of the CGP and CGP-HA/TCP scaffolds were superior to the CGP-HA ones. The untreated and CGP-HA groups repaired mostly through fibrosis, while there were evidence of higher bone formation in the autograft, CGP and CGP-HA/TCP groups. In conclusion, addition of HA or ß-TCP alone into the CGP scaffolds impaired bone regeneration, while bone regeneration with the CGP and CGP-HA/TCP scaffolds was comparable with the autograft. Therefore, the CGP-HA/TCP scaffold can be a possible option to substitute the autologous bone grafting.

Histopathological and biomechanical evaluation of bone healing properties of DBM and DBM-G90 in a rabbit model.

OBJECTIVE: The present study was designed to investigate the effects of DBM and DBM-G90 on bone healing in a rabbit model. METHODS: Thirty male white albino rabbits were used in this study. An incision was made in all rabbits under general anesthesia directly over the radius in order to expose it. A 10-mm segmental defect was created on the middle portion of each radius. The defects of 10 rabbits (Group I) were filled with DBM Block and Strip (Zimmer, Inc., Warsaw, IN, USA), the defects of 10 rabbits (Group II) were filled with DBM soaked in G90, and the defects of 10 rabbits (Group III/control) were left empty. The rabbits were euthanized at 60 days postoperatively for histopathological and biomechanical evaluation. RESULTS: At the histopathologic level, the defects of the animals in the DBM and DBM-G90 groups showed more advanced healing criteria than those of the control group. In biomechanical findings, there was a statistically significant difference between the injured bones and contralateral normal bones of the control group in terms of measured strength. There was not a statistically significant difference between the treated bones of the DBM and DBM-G90 groups with contralateral normal bones, nor was there a statistically significant difference between the treated bones of the DBM and DBM-G90 groups with the treated bones of the control group, in terms of other biomechanical tests. CONCLUSION: Based on the histopathological and biomechanical findings, the DBM and DBM-G90 groups demonstrated superior osteogenic potential; however, G90 shows no superiority over DBM on bone healing.

Synthesis, development, characterization and effectiveness of bovine pure platelet gel-collagen-polydioxanone bioactive graft on tendon healing.

Bovine platelet gel (BPG) is an accessible and cost-effective source of growth factors which may have a value in tendon regenerative medicine. We produced a collagen implant (CI) as a tendon proper, covered it with polydioxanone (PDS) sheath to simulate paratenon and finally embedded the BPG as an active source of growth factor within the bioimplant to test whether BPG would be able to accelerate and enhance tendon regeneration and repair. After in vitro characterization of the bioactive grafts, the grafts were implanted in rabbit large tendon defect model. Untreated tendons and tendons treated with either CI or CI-PDS were served as controls for the CI-PDS-BPG. The animals were investigated clinically, ultrasonographically and haematologically for 120 days. After euthanasia, dry matter content, water uptake and delivery characteristics and also gross morphological, histopathological and scanning electron microscopic features of the healing tendons were assessed. In vitro, the activated platelets in the scaffold, released their growth factors significantly more than the controls. BPG also increased cell viability, and enhanced cellular differentiation, maturation and proliferation inside the CI-PDS compared with the controls. In vivo, the BPG modulated inflammation, increased quality and rate of fibroplasia and produced a remodelled tendon that had significantly higher collagen content and superior collagen fibril and fibre differentiation than controls. Treatment also significantly improved tendon water uptake and delivery characteristics, animals' serum PDGF level, CI-PDS biocompatibility and biodegradability and reduced peritendinous adhesions, muscle fibrosis and atrophy. BPG was effective on tendon healing and CI-PDS-BPG may be a valuable bioscaffold in tendon reconstructive surgery.

Role of xenogenous bovine platelet gel embedded within collagen implant on tendon healing: an in vitro and in vivo study.

Surgical reconstruction of large Achilles tendon defects is demanding. Platelet concentrates may be useful to favor healing in such conditions. The characteristics of bovine platelet-gel embedded within a collagen-implant were determined in vitro, and its healing efficacy was examined in a large Achilles tendon defect in rabbits. Two cm of the left Achilles tendon of 60 rabbits were excised, and the animals were randomly assigned to control (no implant), collagen-implant, or bovine-platelet-gel-collagen-implant groups. The tendon edges were maintained aligned using a Kessler suture. No implant was inserted in the control group. In the two other groups, a collagen-implant or bovine-platelet-gel-collagen-implant was inserted in the defect. The bioelectricity and serum platelet-derived growth factor levels were measured weekly and at 60 days post injury, respectively. After euthanasia at 60 days post injury, the tendons were tested at macroscopic, microscopic, and ultrastructural levels, and their dry matter and biomechanical performances were also assessed. Another 60 rabbits were assigned to receive no implant, a collagen-implant, or a bovine-platelet-gel-collagen-implant, euthanized at 10, 20, 30, and 40 days post injury, and their tendons were evaluated grossly and histologically to determine host-graft interactions. Compared to the control and collagen-implant, treatment with bovine-platelet-gel-collagen-implant improved tissue bioelectricity and serum platelet-derived growth factor levels, and increased cell proliferation, differentiation, and maturation. It also increased number, diameter, and density of the collagen fibrils, alignment and maturation of the collagen fibrils and fibers, biomechanical properties and dry matter content of the injured tendons at 60 days post injury. The bovine-platelet-gel-collagen-implant also increased biodegradability, biocompatibility, and tissue incorporation behavior of the implant compared to the collagen-implant alone. This treatment also decreased tendon adhesion, muscle fibrosis, and atrophy, and improved the physical activity of the animals. The bovine-platelet-gel-collagen-implant was effective in neotenon formation in vivo, which may be valuable in the clinical setting.

Role of embedded pure xenogenous bovine platelet gel on experimental tendon healing, modelling and remodelling.

BACKGROUND AND OBJECTIVES: Surgical reconstruction of large tendon defects is technically demanding. In addition, tendon healing has poor quality and is associated with development of peritendinous adhesions. Tissue engineering and regenerative medicine is an option. A combination of scaffolds and factors that promote healing, such as a bioactive graft, could be a valuable strategy for treatment of the injured tendons. Different forms of platelets have been used for tendon healing. Since the availability and cost effectiveness of biomaterials are important in tissue engineering, bovine platelets could be a valuable alternative option for the autograft platelets. We investigated whether bovine platelet gel embedded within an artificial tendon could be effective in tendon healing and regeneration, in vivo. METHODS: After in vitro evaluations, a large tendon defect model was produced in rabbits and the defect maintained align using Kessler suture. The animals were divided into four groups of control (no implant), treatment with collagen implant, collagen implant-polydioxanone sheath, and collagen implant-polydioxanone sheet-bovine platelet gel. The healing and regeneration were assessed by gross- micro- and nano-morphologic analyses, biomechanical testing, biochemistry, bioelectricity, and clinical evaluations at 60 and 120 days after injury. RESULTS: Bovine platelet gel induced cellular proliferation and enhanced cell viability in vitro. In vivo, it significantly increased inflammation in the short term, enhanced cellular distribution, proliferation, migration, differentiation and matrix production at mid-term and finally it facilitated graft degradation, incorporation and acceptance in the newly regenerated tendon. Compared with the control groups, the platelet-treated neotendon had significantly higher mechanical strength which was due to the collagen fibril's better density, diameter, number, differentiation and distribution, collagen fibril to fiber and fiber bundle differentiation and lower peritendinous adhesion, muscle fibrosis and atrophy. CONCLUSION: Bovine platelet gel-embedded artificial tendon could be considered as a new option in reconstruction and healing of large tendon defects.

Effectiveness of xenogenous-based bovine-derived platelet gel embedded within a three-dimensional collagen implant on the healing and regeneration of the Achilles tendon defect in rabbits.

BACKGROUND AND OBJECTIVE: Tissue engineering is an option in reconstructing large tendon defects and managing their healing and regeneration. We designed and produced a novel xenogeneic-based bovine platelet, embedded it within a tissue-engineered collagen implant (CI) and applied it in an experimentally induced large tendon defect model in rabbits to test whether bovine platelets could stimulate tendon healing and regeneration in vivo. METHODS: One hundred twenty rabbits were randomly divided into two experimental and pilot groups. In all the animals, the left Achilles tendon was surgically excised and the tendon edges were aligned by Kessler suture. Each group was then divided into three groups of control (no implant), treated with CI and treated with collagen-platelet implant. The pilot groups were euthanized at 10, 15, 30 and 40 days post-injury (DPI), and their gross and histologic characteristics were evaluated to study host-graft interaction mechanism. To study the tendon healing and its outcome, the experimental animals were tested during the experiment using hematologic, ultrasonographic and various methods of clinical examinations and then euthanized at 60 DPI and their tendons were evaluated by gross pathologic, histopathologic, scanning electron microscopic, biophysical and biochemical methods. RESULTS: Bovine platelets embedded within a CI increased inflammation at short term while it increased the rate of implant absorption and matrix replacement compared with the controls and CI alone. Treatment also significantly increased diameter, density, amount, alignment and differentiation of the collagen fibrils and fibers and approximated the water uptake and delivery behavior of the healing tendons to normal contralaterals (p < 0.05). Treatment also improved echogenicity and homogenicity of the tendons and reduced peritendinous adhesion, muscle fibrosis and atrophy, and therefore, it improved the clinical scores and physical activity related to the injured limb when compared with the controls (p < 0.05). CONCLUSION: The bovine platelet gel embedded within the tissue-engineered CI was effective in healing, modeling and remodeling of the Achilles tendon in rabbit. This strategy may be a valuable option in the clinical setting.

In vitro characterization of a novel tissue engineered based hybridized nano and micro structured collagen implant and its in vivo role on tenoinduction, tenoconduction, tenogenesis and tenointegration.

Surgical reconstruction of large tendon defects is technically demanding. Tissue engineering is a new option. We produced a novel tissue engineered, collagen based, bioimplant and in vitro characterizations of the implant were investigated. In addition, we investigated role of the collagen implant on the healing of a large tendon defect model in rabbits. A two cm length of the left rabbit's Achilles tendon was transected and discarded. The injured tendons of all the rabbits were repaired by Kessler pattern to create and maintain a 2 cm tendon gap. The collagen implant was inserted in the tendon defect of the treatment group (n = 30). The defect area was left intact in the control group (n = 30). The animals were euthanized at 60 days post injury (DPI) and the macro- micro- and nano- morphologies and the biomechanical characteristics of the tendon samples were studied. Differences of P < 0.05 were considered significant. The host graft interaction was followed at various stages of tendon healing, using pilot animals. At 60 DPI, a significant increase in number, diameter and density of the collagen fibrils, number and maturity of tenoblasts and tenocytes, alignment of the collagen fibrils and maturity of the elastic fibers were seen in the treated tendons when compared to the control ones (P < 0.05). Compared to the control lesions, number of inflammatory cells, amount of peritendinous adhesions and muscle fibrosis and atrophy, were significantly lower in the treated lesions (P < 0.05). Treatment also significantly increased load to failure, tensile strength and elastic modulus of the samples as compared with the control ones. The collagen implant properly incorporated with the healing tissue and was replaced by the new tendinous structure which was superior both ultra-structurally and physically than the loose areolar connective tissue regenerated in the control lesions. The results of this study may be valuable in the clinical practice.

Implantation of a novel tissue-engineered graft in a large tendon defect initiated inflammation, accelerated fibroplasia and improved remodeling of the new Achilles tendon: a comprehensive detailed study with new insights.

We constructed a new artificial collagen-based graft as a tendon proper and covered it with a polydioxanone sheath. This bioimplant was tested in vitro and also its effectiveness was tested in a large tendon defect model in vivo. A 2-cm full defect in the left Achilles tendon of all animals (n = 120) was created. The animals were andomly divided into three groups: control (n = 40), treated with collagen-based graft (n = 40) and treated with collagen-Polydioxanone-based graft (n = 40). Clinical examination was done weekly. The animals were euthanized at 60 and 120 days post-injury (DPI). The serum level of platelet-derived growth factor (PDGF) was measured. Hydroxyproline and dry matter content together with gross morphologic, histomorphometric, ultrastructural and biomechanical characteristics of the healing tissues were studied. The mechanism of host-graft interactions was studied in another 55 pilot animals. The graft was able to initiate inflammation, accelerate fibroplasia and improve remodeling of the neotenon in the defect area. Except for small remnants, most parts of the implants were gradually absorbed and substituted by a newly regenerated tendon. The preserved remnants were accepted as a part of neotenon and acted as scaffolds for the newly regenerated collagen fibrils. Unlike the controls, the treated lesions showed lower peritendinous adhesion, muscle fibrosis and atrophy and higher hydroxyproline concentration, dry matter content, ultimate strength, yield strength and modulus of elasticity. Numbers, diameter, density and differentiation of collagen fibrils were also greater in the treated lesions than the control ones. This study showed that the implant was cytocompatible, biodegradable, biocompatible and effective in tendon healing.

Tendon tissue engineering and its role on healing of the experimentally induced large tendon defect model in rabbits: a comprehensive in vivo study.

Healing of large tendon defects is challenging. We studied the role of collagen implant with or without polydioxanone (PDS) sheath on the healing of a large Achilles tendon defect model, in rabbits. Sixty rabbits were divided into three groups. A 2 cm gap was created in the left Achilles tendon of all rabbits. In the control lesions, no implant was used. The other two groups were reconstructed by collagen and collagen-PDS implants respectively. The animals were clinically examined at weekly intervals and their lesions were observed by ultrasonography. Blood samples were obtained from the animals and were assessed for hematological analysis and determination of serum PDGF level, at 60 days post injury (DPI). The animals were then euthanized and their lesions were assessed for gross and histopathology, scanning electron microscopy, biomechanical testing, dry matter and hydroxyproline content. Another 65 pilot animals were also studied grossly and histopathologically to define the host implant interaction and graft incorporation at serial time points. The treated animals gained significantly better clinical scoring compared to the controls. Treatment with collagen and collagen-PDS implants significantly increased the biomechanical properties of the lesions compared to the control tendons at 60DPI (P<0.05). The tissue engineered implants also reduced peritendinous adhesion, muscle fibrosis and atrophy, and increased ultrasonographical echogenicity and homogenicity, maturation and differentiation of the collagen fibrils and fibers, tissue alignment and volume of the regenerated tissue compared to those of the control lesions (P<0.05). The implants were gradually absorbed and substituted by the new tendon. Implantation of the bioimplants had a significant role in initiating tendon healing and the implants were biocompatible, biodegradable and safe for application in tendon reconstructive surgery. The results of the present study may be valuable in clinical practice.