Effects of a serotonin S2-receptor blocker on healing of acute and chronic tendon injuries

Healing potential of curcumin nanomicelles in cutaneous burn wounds: an in vitro and in vivo study

PURPOSE/AIM OF THE STUDY

Curcumin is the active substance of turmeric and has been shown to enhance the healing potential of burn wounds. However, its high hydrophobicity and rapid degradability are great challenges for its clinical applications. The development of new curcumin formulations may provide a potential solution to these issues.

METHODS AND RESULTS

In this study, we investigated the use of curcumin nanomicelles for wound dressing and evaluated their effects on fibroblast migration and proliferation in vitro. We found that the application of curcumin nanomicelles to the wounds significantly improved wound contraction and increased the expression of transforming growth factor-1 and basic fibroblast growth factor at day 14 of the healing process. Furthermore, curcumin nanomicelles reduced the expression of interleukin-1 at days 7 and 14 post-wounding. Histopathological analysis revealed that the curcumin nanomicelles-treated burn wounds exhibited more organized granulation tissue, improved angiogenesis, and enhanced re-epithelialization. Additionally, the curcumin treatment led to increased hydroxyproline content and enhanced TGF-β1 expression level in the wounds. The in vitro studies also demonstrated that the curcumin nanomicelles induced proliferation and migration of fibroblasts.

CONCLUSION

Overall, our findings suggest that curcumin nanomicelles can be a promising candidate for the treatment of burn wounds.

Kefir Accelerates Burn Wound Healing Through Inducing Fibroblast Cell Migration In Vitro and Modulating the Expression of IL-1ß, TGF-ß1, and bFGF Genes In Vivo

Kefir is a natural probiotic compound with a long history of health benefits which can improve wound healing. This study investigated the regeneration potential of kefir in vitro scratch assay and in vivo burn wound in rat model. Cytotoxicity of different concentrations of kefir was evaluated by colorimetric methylthiazoltetrazolium assay. A scratch wound experiment was performed to investigate the ability of kefir in reducing the gap of wounds in a dose-dependent manner, in vitro. The standardized kefir was incorporated into silver sulfadiazine (SSD) and applied on burn wounds in vivo, and was compared with the SSD and negative control groups after 7, 14, and 28 days of treatment. The wound sites were then removed for histopathological and morphometric analyses, assessment of interleukin-1β (IL-1β), transforming growth factor-β1 (TGF-β1), basic fibroblast growth factor (bFGF), dry weight, and hydroxyproline contents. Kefir enhanced proliferation and migration of human dermal fibroblast (HDF) cells and 12.50, 6.25, and 3.12 μL/mL concentrations showed better effects on the scratch assay. Kefir resulted in reduction of IL-1β and TGF-β1 expression at day 7 compared to the negative control. Kefir also reduced the expression of IL-1β at days 14 and 28 and stimulated bFGF at day 28. It significantly improved the dry matter and hydroxyproline contents in the burn wounds. Kefir also resulted in enhanced angiogenesis and elevated migration and proliferation of fibroblasts and improved fibrous connective tissue formation in the wound area. The morphometric results indicated significant global contraction values in the kefir-treated wounds compared to other groups. Taken together, the findings suggest that kefir has considerable ability to accelerate healing of the burn wounds. Therefore, kefir may be a possible option to improve the outcomes of severe burns.

Application of honey as a protective material in maintaining the viability of adipose stem cells in burn wound healing: A histological, molecular and biochemical study

Enhanced resistance to oxidative stress makes the adipose stem cells (ASCs) able to promote wound repair and regeneration. Such cells can be achieved by addition of an anti-oxidant to cell culture medium. In this study, a combination of honey (H) and ASCs was applied on burn wounds and the injured area was then covered by a tegaderm (T) dressing in a rat model. Wound healing was evaluated by histopathological, histomorphometrical, molecular, scanning electron microscopy, and biochemical assessments on days 7, 14, and 28 post-wounding. Treatment with ASCs-containing honey (T-H/ASC) resulted in substantial reduction in the level of pro-inflammatory cytokines including interleukin-1β (IL-1β) and transforming growth factor-β1 (TGF-β1) in wound bed, at 7 day post-surgery. T-H/ASCs also elevated the level of bFGF expression, indicating that ASCs enhanced angiogenesis, at 7 day post-wounding. T-H/ASCs significantly improved angiogenesis, re-epithelialization, and granulation tissue formation compared to other treatment regimes, at 14 day post-surgery. These outcomes were in exceptionally good agreement with the histological and biochemical findings. Increased bFGF level in the T-H/ASCs treated wounds at the 28th day post-surgery showed the anti-scarring activity of ASCs. Honey can be considered as a protective material in maintaining the viability of ASCs and improving the cellular resistance to oxidative stress. Furthermore, combination of ASCs and honey can provide a nutrient media for the ASCs and enhance the ability of regeneration of the ASC-based therapies.

Healing potential of injectable Aloe vera hydrogel loaded by adipose-derived stem cell in skin tissue-engineering in a rat burn wound model

Adipose stem cells (ASCs) are a great promise in wound healing due to their potential in differentiating into various cell lineages and secreting growth factors. The purpose of this study is to evaluate the in vivo effects of Aloe vera hydrogel loaded by allogeneic ASCs on a rat burn wound model. The ASCs were isolated, cultured and mixed with 50% Aloe vera hydrogel and injected intradermally around the wound. Demineralized bone matrix (DBM) was used as dressing in the experiment. The burn wound-healing properties of different experimental groups were investigated by histopathological, molecular, scanning electron microscopic and biochemical analysis at the 7th, 14th and 28th days post-wounding. The Aloe vera and DBM-Aloe vera groups showed almost similar healing properties, while treatment by DBM-Aloe vera/ASCs significantly enhanced wound healing. The levels of transforming growth factor-β1 (TGF-β1) and interleukin-1β markedly decreased at the 7th day post-injury, in the DBM-Aloe vera/ASC-treated group, suggesting that this treatment regime subsided the inflammatory responses. Angiogenesis, re-epithelialization and the level of TGF-β1 in the wounds treated with DBM-Aloe vera/ASCs were also remarkably higher than those of other groups, at the 14th day post-injury. Besides, scar formation significantly decreased in the DBM-Aloe vera/ASC-treated wounds when compared with other groups. Our biochemical results were in agreement with the molecular and histopathological findings and strongly demonstrated that a DBM-Aloe vera/ASC composite can stimulate burn wound healing. These results suggest that the DBM-Aloe vera/ASC composite can be considered as a promising therapeutic strategy in the treatment of burn wounds.

The role of three-dimensional pure bovine gelatin scaffolds in tendon healing, modeling, and remodeling: an in vivo investigation with potential clinical value

AIM OF THE STUDY

Large tendon defects involving extensive tissue loss present complex clinical problems. Surgical reconstruction of such injuries is normally performed by transplanting autogenous and allogenous soft tissues that are expected to remodel to mimic a normal tendon. However, the use of grafts has always been associated with significant limitations. Tissue engineering employing artificial scaffolds may provide acceptable alternatives. Gelatin is a hydrolyzed form of collagen that is bioactive, biodegradable, and biocompatible. The present study has investigated the suitability of gelatin scaffold for promoting healing of a large tendon-defect model in rabbits.

MATERIALS AND METHODS

An experimental model of a large tendon defect was produced by partial excision of the Achilles tendon of the left hind leg in adult rabbits. To standardize and stabilize the length of the tendon defect a modified Kessler core suture was anchored in the sectioned tendon ends. The defects were either left untreated or filled with three-dimensional gelatin scaffold. Before euthanasia 60 days after injury, the progress of healing was evaluated clinically. Samples of healing tendon were harvested at autopsy and evaluated by gross, histopathologic, scanning, and transmission electron microscopy, and by biomechanical testing.

RESULTS

The treated animals showed superior weight-bearing and physical activity compared with those untreated, while frequency of peritendinous adhesions around the healing site was reduced. The gelatin scaffold itself was totally degraded and replaced by neo-tendon that morphologically had significantly greater numbers, diameters, density, and maturation of collagen fibrils, fibers, and fiber bundles than untreated tendon scar tissue. It also had mechanically higher ultimate load, yield load, stiffness, maximum stress and elastic modulus, when compared to the untreated tendons.

CONCLUSION

Gelatin scaffold may be a valuable option in surgical reconstruction of large tendon defects.

Protective effects of melatonin on long-term administration of fluoxetine in rats

The degree and consequence of tissue injury are highly regarded during long-term exposure to selective antidepressant fluoxetine. Melatonin has been shown to palliate different lesions by scavenging free radicals, but its role in the reduction of the fluoxetine-induced injuries has been little known. Thirty-six mature male Wistar rats were randomly assigned into control and experimental groups. The experimental rats were included as following; 24mg/kg/bw fluoxetine for 4 weeks; 1mg/kg/bw melatonin for 4 weeks; fluoxetine+1-week melatonin, fluoxetine+2-week melatonin and fluoxetine+4-week melatonin. In the current experiment, we investigated weight gain, hematological and biochemical parameters, pathological injuries and oxidative status. We noted the positive effect of melatonin in weight loss of fluoxetine-treated rats (p<0.05). The significant reduction of superoxide dismutase, glutathione peroxidase, catalase activities in blood, liver, and kidneys and changes in serum total antioxidant capacity caused by fluoxetine were reversed by melatonin (p<0.05). Melatonin reduced the increased lipid peroxidation and transaminase activity in rats received fluoxetine (p<0.05). We also showed the potency of fluoxetine in inducing leukopenia, thrombocytopenia and hypochromic and macrocytic anemia which was blunted by melatonin. Both RBCs and platelets indices were also corrected. Rats received melatonin in combination with fluoxetine showed a reduction in the severity of degeneration and inflammatory changes in different tissues, brain, heart, liver, lungs, testes and kidneys as compared to the fluoxetine group. Therefore, melatonin fundamentally reversed the side effects of fluoxetine in the rat model which is comparable to human medicine.

Avocado/soybean unsaponifiables: a novel regulator of cutaneous wound healing, modelling and remodelling

We investigated the effects of avocado/soybean unsaponifiables (ASU) on the healing response of cutaneous wound defect in rats. Sixty male rats were randomly divided into three groups including control, vehicle and treatment (n = 20 in each group). A 2 × 2 cm(2) wound defect was made on the dorsum. The control, vehicle and treatment groups were treated daily with topical application of saline, cream and cream/ASU for 10 days, respectively. The wounds were monitored daily. The animals were euthanised at 10, 20 and 30 days post injury (D). The dry matter, hydroxyproline, collagen, n-acetyl glucosamine (NAGLA) and n-acetyl galactosamine (NAGAA) contents of the skin samples were measured and the histopathological and biomechanical characteristics of the samples were investigated. Statistics of P < 0·05 was considered significant. Treatment significantly increased tissue glycosaminoglycans and collagen contents at various stages of wound healing compared to controls. Treatment modulated inflammation, improved fibroplasia and produced high amounts of scar tissue at short term. At long term, treatment reduced the scar tissue size and increased the quality and rate of wound contraction and reepithelisation compared to controls. The treated lesions were more cosmetically pleasing and had significantly higher biomechanical characteristics than controls. ASU was effective in rat wound healing.

Role of tissue engineered collagen based tridimensional implant on the healing response of the experimentally induced large Achilles tendon defect model in rabbits: a long term study with high clinical relevance

Background

Tendon injury is one of the orthopedic conditions poses with a significant clinical challenge to both the surgeons and patients. The major limitations to manage these injuries are poor healing response and development of peritendinous adhesions in the injured area. This study investigated the effectiveness of a novel collagen implant on tendon healing in rabbits.

Results

Seventy five mature White New-Zealand rabbits were divided into treated (n = 55) and control (n = 20) groups. The left Achilles tendon was completely transected and 2 cm excised. The defects of the treated animals were filled with collagen implants and repaired with sutures, but in control rabbits the defects were sutured similarly but the gap was left untreated. Changes in the injured and normal contralateral tendons were assessed weekly by measuring the diameter, temperature and bioelectrical characteristics of the injured area. Clinical examination was done and scored. Among the treated animals, small pilot groups were euthanized at 5, 10, 15, 20, 30, 40 and 60 (n = 5 at each time interval) and the remainder (n = 20) and the control animals at 120 days post injury (DPI). The lesions of all animals were examined at macroscopic and microscopic levels and the dry matter content, water delivery and water uptake characteristics of the lesions and normal contralateral tendons of both groups were analyzed at 120 DPI.

No sign of rejection was seen in the treated lesions. The collagen implant was invaded by the inflammatory cells at the inflammatory phase, followed by fibroplasia phase in which remnant of the collagen implant were still present while no inflammatory reaction could be seen in the lesions. However, the collagen implant was completely absorbed in the remodeling phase and the newly regenerated tendinous tissue filled the gap. Compared to the controls, the treated lesions showed improved tissue alignment and less peritendinous adhesion, muscle atrophy and fibrosis. They also showed significantly better clinical scoring, indices for water uptake and water absorption, and bioelectrical characteristics than the controls.

Conclusion

This novel collagen implant was biodegradable, biocompatible and possibly could be considered as a substitute for auto and allografts in clinical practice in near future.

Novel application of a tissue-engineered collagen-based three-dimensional bio-implant in a large tendon defect model: a broad-based study with high value in translational medicine

This study was designed to investigate the effectiveness of a novel tissue-engineered three-dimensional collagen implant on healing of a large tendon-defect model, in vivo. Forty rabbits were divided into two equal groups: treated and control. A 2cm full-thickness gap was created in the left Achilles tendons of all the rabbits. To maintain the gap at the desired length (2cm), a Kessler suture was anchored within the proximal and distal ends of the remaining tendon. In the treated group a collagen implant was inserted in the gap while in the control group the gap was left unfilled. At weekly intervals the animals were examined clinically and their Achilles tendons tested bioelectrically. The hematological parameters and the serum Platelet-Derived Growth Factor of the animals were analyzed at 60 days post injury (DPI) immediately prior to euthanasia. Their injured (left) and normal contralateral Achilles tendons were harvested and examined at gross morphologic level before being subjected to biomechanical testing, and biophysical and biochemical analysis. The treated animals showed superior weight-bearing and greater physical activity than their controls. New dense tendinous tissue with a transverse diameter comparable to that of intact tendons filled the defect area of the treated tendons and had entirely replaced the collagen implant, at 60 DPI. In control lesions the defect was filled with loose areolar connective tissue similar to subcutaneous fascia. Treatment significantly improved the electrical resistance, dry matter, hydroxyproline content, water uptake and water delivery characteristics, of the healing tissue, as well as maximum load, yield load, maximum stress, yield stress and modulus of elasticity of the injured treated tendons compared to those of the control tendons (P<0.05). Use of this three-dimensional collagen implant improved the healing of large tendon defects in rabbits.

A novel application of biosynthetic tissue-engineered tridimensional implant on large tendon defects: a comprehensive, detailed, in vivo investigation with significant clinical value

This study was designed to investigate the effect of a biosynthetic implant on tendon healing in vivo. Fifty white New Zealand male rabbits were randomly divided into two groups, namely treated (n = 25) and control (n = 25) groups. A large gap was created in the Achilles tendon and was maintained by Kessler pattern. In the treated group, the implant was inserted in the injured area. No implant was used in the control group. Contrast radiography, hematology, and clinical examination were conducted during the course of the experiment. The animals were euthanized at 60 days post injury (DPI) and their Achilles tendons were subjected to the gross, histopathologic, and biomechanical analyses and the hydroxyproline content of these tendons was also evaluated. Another five treated animals, as a pilot group, were used to define the inflammatory reaction at 10 DPI. Severe inflammatory reaction was initiated by the partially degraded implant, at 10 DPI. However, at 60 DPI, the inflammation subsided, the implant was mostly removed but a few small remnants were still present in the injured area. The newly formed tendon, properly aligned along the longitudinal axis of the Achilles tendon replaced the collagen implant. In the control tendons, a loose areolar connective tissue which tightly adhered to the peri-tendinous tissue was the only regenerated structure in the injured area. At this stage, the treated tendons showed significantly higher ultimate strength (p = 0.001), yield strength (p = 0.001), and stiffness (p = 0.001) compared with the control ones. Application of the biosynthetic implant was a safe and effective option in managing the large tendon defects and could be considered as a substitute for autografts in clinical practice.

Repeated administration of exogenous Sodium-hyaluronate improved tendon healing in an in vivo transection model

GOALS AND OBJECTIVES

This study was designed to evaluate the effects of exogenous Sodium-Hyaluronate (NaH) on full thickness Superficial Digital Flexor Tendon (SDFT) rupture in the early phase of healing in rabbits.

METHODS

Forty White New Zealand mature male rabbits were randomly divided into two equal groups of injured treated and injured untreated. After full thickness tendon transection and surgical repair, using modified Kessler technique and running suture, the injured legs were casted for 14 days. Sodium-Hyaluronate was injected subcutaneously over the lesion on days 3, 7 and 10 post-injury (DPI). The control animals received normal saline injection following the same protocol. Weight of the animals, tendon diameter, ultrasonographic evaluations was conducted at weekly intervals. The rabbits were euthanized on 28 DPI and the tendons were assessed for macroscopic, histopathologic, ultrastructural, and percentage dry weight analysis.

RESULTS

Although there was no significant difference in the radiographs of the treated and untreated lesions, treatment significantly reduced tendon diameter, ultimate and yield strain and increased echogenicity and dry weight content of the injured tendons compared to those of the untreated ones. Treatment also significantly enhanced the maturation rate of the tenoblasts, diameter and density of the collagen fibrils.

CONCLUSION

Treatment of NaH has been shown to be effective in restoring the morphological and biomechanical properties of lacerated SDFT of rabbits and may be valuable in the clinical trial studies.

Novel application of Theranekron® enhanced the structural and functional performance of the tenotomized tendon in rabbits

The effects of Tarantula cubensis extract (TC; Theranekron®) on the experimentally induced rupture of the superficial digital flexor tendon (SDFT) 28 days post-injury (DPI) was studied in rabbits. Forty mature White New Zealand male rabbits were randomly divided into two groups. TC was repeatedly injected subcutaneously over the lesion 3, 7 and 10 days after tenotomy and surgical anastomosis. Clinical and ultrasonographic evaluations were conducted at weekly intervals. The animals were euthanized 28 DPI and the tendons were investigated for macroscopic, histopathologic, ultrastructural, biomechanical and percent dry weight parameters. Treatment reduced signs of acute inflammation and strongly ameliorated clinical symptoms, structural organization and biomechanical properties (p < 0.05). Apparently, TC is effective in restoring the clinical, morphological and biomechanical properties of the injured SDFT in rabbits and may be valuable in human and veterinary medicine.

Recombinant fibroblast growth protein enhances healing ability of experimentally induced tendon injury in vivo

This study was designed to investigate the effects of recombinant human basic fibroblast growth factor (bFGF) on a complete superficial digital flexor tendon (SDFT) rupture after surgical repair in rabbits. Eighty mature New Zealand White rabbits of both sexes were randomly divided into two equal groups: Treated and Control. Each group was subdivided into two 28- and 84-day post-injury subgroups. After tenotomy and surgical repair, the animals were immobilized for 14 days. In the treated group, bFGF was directly applied subcutaneously over the lesion on days 3, 7 and 10 after injury. The control animals received normal saline injection of the same viscosity and volume and at the same intervals. Ultrasonographical observations were conducted at weekly intervals. The animals were euthanized at 28 and 84 days after injury. The tendons were evaluated at macroscopic, histopathologic and ultrastructural levels and were assessed for biomechanical and percentage dry weight parameters. Compared to injured control animals, treated animals showed a decrease in the diameter of the injured tendon and peritendinous adhesion as well as increased tenoblast proliferation, collagen production and ultimate strength of the injured tendons (p < 0.005). At 84 days after injury, treatment resulted in enhanced maturation of the cellular and collagen elements and improved tissue alignment and density. These improvements resulted in increased biomechanical performance of the injured tendons compared to controls (p = 0.001). bFGF showed promising curative effects on restoration of the biomechanical and morphological properties of the ruptured SDFT in rabbits and may be applicable in clinical studies.

Short and long terms healing of the experimentally transverse sectioned tendon in rabbits

Background

The incidences of tendon injuries in certain sections of human or animal populations such as athletes are high, but every human or animal, regardless of age or level of activity experiences some degree of tendon injury. In spite of the various investigations of injuries and treatment, comprehensive studies dealing with the histological, ultrastructural and biomechanical aspects of healing of load-bearing tendons are rare. This study was designed to compare the outcome of healing of the transverse sectioned superficial digital flexor tendon (SDFT) after 28 and 84 days post injury (DPI) in rabbits.

Methods

Forty white New Zealand mature female rabbits were randomly divided into two equal groups of 28 and 84 DPI After tenotomy and surgical repair of the left SDFT, the injured legs were casted for 14 days. The weight of the animals, tendon diameter, and clinical, radiographic and ultrasonographic evaluations were conducted at weekly intervals. The animals were euthanized on 28 and 84 DPI and the tendons were evaluated for histopathological, ultrastructural, biomechanical and percentage dry weight parameters.

Results

Although the clinical, ultrastructural, morphological and biomechanical properties of the injured tendons on day 84 showed a significant improvement compared to those of the 28 DPI, these parameters were still significantly inferior to their normal contra-lateral tendons.

Conclusions

This study showed that tendon healing is very slow and at 84 days post-injury the morphological and biomechanical parameters were still inferior to the normal tendons and many collagen fibrils still had the same diameter as those seen at 28 DPI.

Effects of sodium-hyaluronate and glucosamine-chondroitin sulfate on remodeling stage of tenotomized superficial digital flexor tendon in rabbits: a clinical, histopathological, ultrastructural, and biomechanical study

This study was designed to evaluate the effects of sodium-hyaluronate (NaH) combined with glucosamine HCl-chondroitin sulfate (GlcN-CS) on the post-surgical repair of tendon rupture on day 84 post injury. Twenty white New Zealand female rabbits were divided randomly into two equal groups of injured treated and injured untreated. After tenotomy and surgical repair, using the modified Kessler technique and running pattern, the injured legs were casted for 14 days. NaH was injected subcutaneously over the lesion on days 3, 7, and 10 and was followed by daily oral administration of GlcN-CS on days 3 to 23 post injury. The control animals received normal saline injection and oral placebo similarly. The weight of the animals, tendon diameter, clinical manifestations, and radiographic and ultrasonographic evaluations were conducted for 12 weeks. The rabbits were euthanized 84 days post injury and the tendons were evaluated at macroscopic, histopathologic, and ultrastructural level and were assessed for biomechanical and percentage dry-weight parameters. Treatment significantly reduced the tendon diameter and ultimate and yield strain, and increased the echogenicity, dry-weight content, ultimate and yield strength, and stress and stiffness of the injured tendons compared to those of the untreated ones. Treatment also significantly enhanced the maturation rate of the tenoblasts, fibrillogenesis, the diameters of the collagen fibrils, and fibrillar density. These findings suggest that a combined treatment of NaH and GlcN-CS could be effective in restoring the morphological and biomechanical properties of injured superficial digital flexor tendon of rabbits and might be helpful for future clinical trial studies in tendon ruptures.