Fish collagen for skin wound healing: a systematic review in experimental animal studies.

Collagen extracted from fishes has been appearing as an alternative for commercial porcine and bovine collagen and it has been considered interesting especially for membrane manufacturing in tissue engineering. Despite the positive in vitro effects of fish collagen membranes, there is still no understanding of all the benefits that this natural biomaterial plays in the wound healing process, due to the lack of compilation of the results obtained in animal studies. In this sense, the purpose of this study was to perform a systematic review of the literature to examine the effects of fish collagen membranes for skin wound healing in experimental models of skin wound. The search was carried out according to the orientations of Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA), and the descriptors of the Medical Subject Headings (MeSH) were defined: "fish," collagen," "skin," and "in vivo". A total of 10 articles were retrieved from the databases PubMed and Scopus. After the elegibility analyses, this review covers the different origins of fish collagen reported in the different papers from the beginning of 2015 through the middle of 2021. The results were based mainly on histological analysis and macroscopic evaluation, and fish skin collagen was responsible for improving the wound healing rate and the process of reepithelization and collagen deposition. In conclusion, fish skin collagen has shown positive results in in vivo studies and may be a potential biomaterial in tissue engineering.

Radiofrequency and skin rejuvenation: a systematic review.

Increasingly, there is an attempt to minimize expression lines through esthetic procedures, and radiofrequency (RF) is one of the therapeutic modalities. This article aims to systematically review the literature on the different types of RF treatment in clinical trials and in variables related to the aging process. This systematic review included 21 articles that treated 354 people with different physical characteristics. The most used RF was the fractional followed by the non-ablative RF. There was a large discrepancy in relation to the types and parameters. A parameter that did not show so much divergence was the temperature, which was between 38°C and 44°C. The main temporary adverse reactions reported by the authors were as follows: discomfort, pain, erythema, hyperpigmentation, crusting, swelling, edema, and purple and acneic appearance of the skin. Finally, our study concluded that non-ablative and ablative RF was reported to rejuvenate and improve the features of skin in all skin types.

Metabolites from Marine Sponges and Their Potential to Treat Malarial Protozoan Parasites Infection: A Systematic Review.

Malaria is an infectious disease caused by protozoan parasites of the Plasmodium genus through the bite of female Anopheles mosquitoes, affecting 228 million people and causing 415 thousand deaths in 2018. Artemisinin-based combination therapies (ACTs) are the most recommended treatment for malaria; however, the emergence of multidrug resistance has unfortunately limited their effects and challenged the field. In this context, the ocean and its rich biodiversity have emerged as a very promising resource of bioactive compounds and secondary metabolites from different marine organisms. This systematic review of the literature focuses on the advances achieved in the search for new antimalarials from marine sponges, which are ancient organisms that developed defense mechanisms in a hostile environment. The principal inclusion criterion for analysis was articles with compounds with IC50 below 10 µM or 10 µg/mL against P. falciparum culture. The secondary metabolites identified include alkaloids, terpenoids, polyketides endoperoxides and glycosphingolipids. The structural features of active compounds selected in this review may be an interesting scaffold to inspire synthetic development of new antimalarials for selectively targeting parasite cell metabolism.

Level of pain, muscle strength and posture: effects of PBM on an exercise program in women with knee osteoarthritis - a randomized controlled trial.

To evaluate the effectiveness of an exercise program associated to photobiomodulation (PBM) on pain, postural changes, functionally, and muscular strength in women, one of the risk factors, with knee osteoarthritis (OA). A randomized controlled trial, with a blinded assessor and intention-to-treat analysis and placebo control. Sixty-two participants with knee OA (with confirmed radiological diagnosis) were evaluated for this study. However, 34 were considered eligible and were randomized into two groups: EPPG - exercise and PBM placebo group (n = 17) and EPAG - exercise and PBM active group (n = 16), but one participant was excluded of EPAG. The exercise program and PBM (808 nm, 100 mW/point, 4 J/point, 56 J total, 91 J/cm2) were realized twice a week, during 8 weeks. West Ontario and the McMaster University Osteoarthritis Index (WOMAC) and Lequesne questionnaires, 1-repetition maximum test (1-RM) and posture evaluation software (SAPO) were used to analyze the effects of the therapies. In intragroup analysis, a significant improvement in pain WOMAC (p < 0.001), stiffness (p < 0.001), function (p < 0.001), Lequesne (p < 0.001), and 1-RM (all muscle groups) (p < 0.001) were observed. In this study, the exercise program improved pain, function, and muscle strength of all the participants. However, PBM, in the parameters used, did not optimize the effects of the exercise program in women with knee OA.

Galvano-puncture and dermabrasion for striae distensae: a randomized controlled trial.

OBJECTIVE: To assess the effects of galvano-puncture (GG) and dermabrasion (DG) in reducing striae distensae in the gluteal region of women. METHODS: This randomized, controlled, single-blind clinical trial was conducted at the UNIFAL-MG. Participants were 48 female who had striae distensae alba in the gluteal region. They were randomly divided in GG; DG; and Control Group (CG). The length and width of the largest striae were measured (in millimeters) using a caliper. The same striae were assessed before and after treatment. Infrared thermography was performed in the gluteal region to assess local microcirculation. RESULTS: Intragroup analysis showed a significant reduction in the dimension of the striae between baseline and treatment session 10 in the GG and DG groups. Between-group analysis revealed a reduction in the width and length of the striae for both the GG and DG groups, but there were no significant differences between the two groups. When compared to the CG and the DG group, the GG group had significant improvements, as shown by thermography. CONCLUSION: Both GG and DG are effective in reducing striae length and width. However, only the thermography results showed significant differences between GG and control, and between GG and DG.

Photobiomodulation effect on the proliferation of adipose tissue mesenchymal stem cells.

The use of mesenchymal stem cells (MSCs) in tissue engineering has been extensively investigated. The greater the proliferation of this cellular group, the greater the regenerative and healing capacity of the tissue to which they belong. In this context, photobiomodulation (PBM) is an efficient technique in proliferation of distinct cell types. However, its parameters and mode of action are still unclear and require further investigation. This study aimed to evaluate the PBM action with different energies in MSCs of adipose tissue (hASCs). We used hASCs, seeded in 24-well plates, with 3 × 104 cells per well, in culture media. We used a total of four experimental groups, one with hASCs and simulated PBM and three other groups, which received PBM irradiation at 24, 48, and 72 h, with a 660-nm laser and power of 40 mW and energy of 0.56, 1.96, and 5.04 J. We performed analyses of MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromidefor) and trypan blue to evaluate cell proliferation and viability, 1 h after PBM irradiation. Software Graph PadPrism 7.0 was used. Intergroup comparisons were performed with ANOVA two-way and we used the Tukey post hoc test. Mitochondrial activity evaluated by MTT revealed the statistical difference in the first 24 h for group with more high energy when compared to control group; and in the 72 h for two irradiated groups when compared to the control group. The trypan blue test showed significant differences at the end of the experiment for two irradiated groups LG1 (4.52 × 104 ± 0.2) and LG2 (4.85 × 104 ± 0.8), when compared to the control group (1.87 × 104 ± 0.7). Both tests failed to be statistically different at the end of the experiment for groups LG1 and LG2 and observed a reduction in cellular mitochondrial growth and activity for group LG3. We conclude that PBM with energy close to 0.56 and 1.96 J promote proliferation of hASCs, and higher energy, such as 5.04 J, can be harmful.

Efficacy and safety of intense pulsed light in rosacea: A systematic review.

Background Rosacea is a chronic inflammatory disease of the skin characterised by facial erythema, oedema, telangiectasias, papules, pustules and nodules. There is a paucity of effective therapeutic modalities for the management of rosacea. Intense Pulsed Light (IPL), a modality in which flash lamps installed in an optical treatment device (head or tip) with mirrors to reflect light, has in recent times gained popularity in the management of this condition. Aim This systematic review aims to evaluate the efficacy, safety and adverse effects of IPL treatment for rosacea. Methods This systematic review was conducted in accordance with the Preferred Reporting Item for Systematic Reviews and Meta-Analysis. The electronic databases searched were Medline, PubMed and Scopus databases. The Risk of bias in non-randomised studies of interventions (ROBINS-I) and risk-of-bias tools for randomised trials (RoB-2) was employed to assess the risk of bias. Results Of a total of 233 articles retrieved from Medline, Scopus and PubMed databases, 14 studies qualified for final analysis. The studies included patients with Fitzpatrick skin types I to IV, with ages ranging from 15 to 78 years. Although the included studies showed heterogeneity between the parameters used, most studies demonstrated positive effects of IPL treatment on telangiectasia and erythema in rosacea and that the adverse effects presented were transitory. Limitation The methodological quality of the included studies was poor. Conclusion Although most studies showed the efficacy of IPL in the treatment of rosacea, the poor quality of the studies was of concern.

Terpenes extracted from marine sponges with antioxidant activity: a systematic review.

Marine biodiversity has emerged as a very promising resource of bioactive compounds and secondary metabolites from different sea organisms. The sponge's secondary metabolites demonstrated various bioactivities and potential pharmacological properties. This systematic review of the literature focuses on the advances achieved in the antioxidant potential of marine sponges in vitro. The review was performed in accordance with PRISMA guidelines. The main inclusion criterion for analysis was articles with identification of compounds from terpene classes that demonstrate antioxidant activity in vitro. Searching in three different databases, two hundred articles were selected. After screening abstracts, titles and evaluating for eligibility of manuscripts 14 articles were included. The most performed analyzes to detect antioxidant activity were scavenging activity 2,2-diphenyl-1-picrylhydrazyl (DPPH) and measurement of intracellular reactive oxygen species (ROS). It was possible to identify 17 compounds of the terpene class with pronounced antioxidant activity in vitro. Scientific evidence of the studies included in this review was accessed by the GRADE analysis. Terpenes play an important ecological role, moreover these molecules have a pharmaceutical and industrial application.

A Review of Cartilage Defect Treatments Using Chitosan Hydrogels in Experimental Animal Models.

INTRODUCTION: Chitosan (CS) is a polycationic polysaccharide comprising glucosamine and N-acetylglucosamine and constitutes a potential material for use in cartilage tissue engineering. Moreover, CS hydrogels are able to promote the expression of cartilage matrix components and reduce inflammatory and catabolic mediator production by chondrocytes. Although all the positive outcomes, no review has analyzed the effects of CS hydrogels on cartilage repair in animal models. METHODS: This study aimed to review the literature to examine the effects of CS hydrogels on cartilage repair in experimental animal models. The search was done by the descriptors of the Medical Subject Headings (MeSH) defined below: "Chitosan," "hydrogel," "cartilage repair," and "in vivo." A total of 420 articles were retrieved from the databases Pubmed, Scopus, Embase, Lilacs, and Web of Science. After the eligibility analyses, this review reported 9 different papers from the beginning of 2002 through the middle of 2022. RESULTS: It was found that cartilage repair was improved with the treatment of CS hydrogel, especially the one enriched with cells. In addition, CS hydrogel produced an upregulation of genes and proteins that act in the cartilage repair process, improving the biomechanical properties of gait. CONCLUSION: In conclusion, CS hydrogels were able to stimulate tissue ingrowth and accelerate the process of cartilage repair in animal studies.

3D-printed hydroxyapatite scaffolds for bone tissue engineering: A systematic review in experimental animal studies.

The use of 3D-printed hydroxyapatite (HA) scaffolds for stimulating bone healing has been increasing over the years. Although all the promising effects of these scaffolds, there are still few studies and limited understanding of their interaction with bone tissue and their effects on the process of fracture healing. In this context, this study aimed to perform a systematic literature review examining the effects of different 3D-printed HA scaffolds in bone healing. The search was made according to the preferred reporting items for systematic reviews and meta-analysis (PRISMA) orientations and Medical Subject Headings (MeSH) descriptors "3D printing," "bone," "HA," "repair," and "in vivo." Thirty-six articles were retrieved from PubMed and Scopus databases. After eligibility analyses, 20 papers were included (covering the period of 2016 and 2021). Results demonstrated that all the studies included in this review showed positive outcomes, indicating the efficacy of scaffolds treated groups in the in vivo experiments for promoting bone healing in different animal models. In conclusion, 3D-printed HA scaffolds are excellent candidates as bone grafts due to their bioactivity and good bone interaction.

3D printed wound constructs for skin tissue engineering: A systematic review in experimental animal models.

Wound dressings are one of the most used treatments for chronic wounds. Moreover, 3D printing has been emerging as a promising strategy for printing 3D printed wound constructs, being able of manufacturing multi layers, with a solid 3D structure. Although all these promising effects of 3D printed wound constructs, there is still few studies and limited understanding of the interaction of these dressings with skin tissue and their effect on the process of skin wound healing. In this context, the aim of this work was to perform a systematic review of the literature to examine the effects of 3D printed wound constructs on the process of skin wound healing in animal models. The articles were selected from three databases following Medical Subject Headings (MeSH) descriptors "3D printing," "skin," "wound," and "in vivo." After the selection, exclusion and inclusion criteria, nine articles were analyzed. This review confirms the significant benefits of using 3D printed wound constructs for skin repair and regeneration. All the used inks demonstrated the ability of mimicking the structure of skin tissue and promoting cell adhesion, proliferation, migration, and mobility. Furthermore, in vivo findings showed full wound closure in most of the studies, with well-organized dermal and epidermal layers.

3D Printed Scaffolds Manufactured with Biosilica from Marine Sponges for Bone Healing in a Cranial Defect in Rats.

The inorganic part of marine sponges, called Biosilica (BS), presents an osteogenic potential and the ability of consolidating fractures. Moreover, 3D printing technique is highly effective for manufacturing scaffolds for tissue engineering proposals. Thus, the aims of this study were to characterize the 3D rinted scaffolds, to evaluate the biological effects in vitro and to investigate the in vivo response using an experimental model of cranial defects in rats. The physicochemical characteristics of 3D printed BS scaffolds were analyzed by FTIR, EDS, calcium assay, evaluation of mass loss and pH measurement. For in vitro analysis, the MC3T3-E1 and L929 cells viability was evaluated. For the in vivo evaluation, histopathology, morphometrical and immunohistochemistry analyses were performed in a cranial defect in rats. After the incubation, the 3D printed BS scaffolds presented lower values in pH and mass loss over time. Furthermore, the calcium assay showed an increased Ca uptake. The FTIR analysis indicated the characteristic peaks for materials with silica and the EDS analysis demonstrated the main presence of silica. Moreover, 3D printed BS demonstrated an increase in MC3T3-E1 and L929 cell viability in all periods analyzed. In addition, the histological analysis demonstrated no inflammation in days 15 and 45 post-surgery, and regions of newly formed bone were also observed. The immunohistochemistry analysis demonstrated increased Runx-2 and OPG immunostaining. Those findings support that 3D printed BS scaffolds may improve the process of bone repair in a critical bone defect as a result of stimulation of the newly formed bone.

Participation of Potential Transient Receptors in the Antinociceptive Effect of Pharmacopuncture.

Background: Despite the widespread clinical use of acupuncture in painful situations, the use of this treatment should be further clarified. Nociception is mediated by the activation of nociceptors, such as transient receptor potentials (TRPs). The family of TRPs includes TRPV1, TRPM8, and TRPA1, which can be stimulated by substances such as capsaicin, menthol, and methyl salicylate, respectively. Objectives: This study aimed to investigate the role of TRPs in antinociception via the administration of agonists of these receptors in the Zusanli acupoint (ST36) in models of inflammatory, acute, and neuropathic pain. Methods: Male Wistar rats were used for this experiment. All rats received a subcutaneous injection of TRP agonists (capsaicin, menthol, or methyl salicylate) in ST36; saline was injected as control. Nociception was evaluated using the electronic mechanical threshold test and tail-flick test before the administration of complete Freund's adjunct or chronic constriction injury of the sciatic nerve and after the administration of TRP agonists. Results: Nociception was found to be attenuated after treatment with TRP agonists. The administration of different doses (0.03, 0.3, and 3.0 µg/20 µL) of capsaicin, menthol, and methyl salicylate in the different pain models (neuropathic, inflammatory, and nociceptive) induced antinociception in most of the evaluated time points. Conclusion: Based on the findings, we suggest that the activation of TRPV1, TRPM8, and TRPA1 receptors results in the antinociceptive effect of the stimulation of the ST36 acupoint. Thus, TRP receptors may present a new therapeutic opportunity for the control of inflammatory and neuropathic pain.

Intense Pulsed Light on skin rejuvenation: a systematic review.

Aged skin is characterized by appearance of wrinkles, vascular lesions, hyperpigmentation, lentignes, texture, rhytides, and pores. These changes occur under the influence of intrinsic and extrinsic factors, as hormone alterations and exposure to ultraviolet light (UV) irradiation, respectively. Skin changes associated with aging have been assuming an important role in nowadays and bring to affect the quality of life. Intense Pulsed Light (ILP) is a noncollimated, polychromatic, and noncoherent non-surgical cosmetic therapy to skin rejuvenation. This is the first systematic review evaluating ILP treatment on skin rejuvenation evaluated by digital photographs and self-reported treatment efficacy. A PRISMA compliant review includes a search of the databases Scopus and PubMed. Sixteen studies treating 637 participants (with Fitzpatrick skin types I to IV and age varying from 21 to 80 years) were included. Patients were treated a mean of 4.29 sessions (range 3-7). The most studies results showed the efficacy of IPL treatment in telangiectasia, wrinkles, pore, erythema, rhytids, texture, lentigines, hiperpigmentation, and photoaging score. Six studies showed IPL-positive effects in association with other treatment and seven studies showed superior effect of other treatment or association to IPL with other treatment related to IPL alone. Nine studies showed low methodological quality. In conclusion, ILP treatment is effective on skin rejuvenation. However, there is no consensus about the parameters and future studies are needed to sample size limitations, made RCTs with low risk of bias, and improve the methodological quality its. Trial registration: Prospero Systematic Review Registration ID: CRD42021237817.

Collagen from Marine Sources and Skin Wound Healing in Animal Experimental Studies: a Systematic Review.

Collagen (Col) from marine organisms has been emerging as an important alternative for commercial Col and it has been considered highly attractive by the industry. Despite the positive effects of Col from marine origin, there is still limited understanding of the effects of this natural biomaterial in the process of wound healing in animal studies. In this context, the purpose of this study was to perform a systematic review of the literature to examine the effects of Col from different marine species in the process of skin tissue healing using experimental models of skin wound. The search was carried out according to the orientations of Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA), and the descriptors of the Medical Subject Headings (MeSH) were defined: "marine collagen," "spongin," "spongin," "skin," and "wound." A total of 42 articles were retrieved from the databases PubMed and Scopus. After the eligibility analyses, this review covers the different marine sources of Col reported in 10 different papers from the beginning of 2011 through the middle of 2019. The results were based mainly on histological analysis and it demonstrated that Col-based treatment resulted in a higher deposition of granulation tissue, stimulation of re-epitalization and neoangiogenesis and increased amount of Col of the wound, culminating in a more mature morphological aspect. In conclusion, this review demonstrates that marine Col from different species presented positive effects on the process of wound skin healing in experimental models used, demonstrating the huge potential of this biomaterial for tissue engineering proposals.

Bone substitutes and photobiomodulation in bone regeneration: A systematic review in animal experimental studies.

In general, bone fractures are able of healing by itself. However, in critical situations such as large bone defects, poor blood supply or even infections, the biological capacity of repair can be impaired, resulting in a delay of the consolidation process or even in non-union fractures. Thus, technologies able of improving the process of bone regeneration are of high demand. In this context, ceramic biomaterials-based bone substitutes and photobiomodulation (PBM) have been emerging as promising alternatives. Thus, the present study performed a systematic review targeting to analyze studies in the literature which investigated the effects of the association of ceramic based bone substitutes and PBM in the process of bone healing using animal models of bone defects. The search was conducted from March and April of 2019 in PubMed, Web of Science and Scopus databases. After the eligibility analyses, 16 studies were included in this review. The results showed that the most common material used was hydroxyapatite (HA) followed by Biosilicate associated with infrared PBM. Furthermore, 75% of the studies demonstrated positive effects to stimulate bone regeneration from association of ceramic biomaterials and PBM. All studies used low-level laser therapy (LLLT) device and the most studies used LLLT infrared. The evidence synthesis was moderate for all experimental studies for the variable histological analysis demonstrating the efficacy of techniques on the process of bone repair stimulation. In conclusion, this review demonstrates that the association of ceramic biomaterials and PBM presented positive effects for bone repair in experimental models of bone defects.

Erythrosine as a photosensitizer for antimicrobial photodynamic therapy with blue light-emitting diodes - An in vitro study.

BACKGROUND: This study aims to test the absorbance of a new composition of erythrosine, its pH, cell viability and potential as a photo sensitizer against Candida albicans when irratiaded with blue light emitting-diode (LED). METHODS: For pH and absorbance tests, erythrosine was prepared at a concentration of 0.03/ml. The cells of the L929 strain were cultured and the alamarBlue® assay was performed on samples to assess cell viability. For the microbiological essay, the strain of Candida albicans ATCC 90028 was selected. Yeast suspensions were divided into the following groups: control without irradiation or photosensitizer (C), irradiated group without photosensitizer (L), photosensitizer group without irradiation (0), and groups that received photosensitizer and irradiation, called aPDT groups. RESULTS: Erythrosine had no significant changes in pH and its absorbance was also consistent (≅400 nm). When it came to cell viability, on the first day, the group that was in contact with the dye and irradiated with the LED in minimun power was found to have the higher cell proliferation. On day 3, both irradiated groups (maximum and minimum) showed the highest cell proliferation. In the microbiological essay with C. albicans, aPDT groups started to show microbial reduction after 60 and 90 s of irradiation and when irradiated for 120 s, 6 microbial reduction logs were found. CONCLUSIONS: The erythrosine in question is a PS, with pH stability, blue light absorbance, cell viability and efficacy against C. albicans. More studies with this PS should be encouraged in order to verify its performance in aPDT.

Effect of photobiomodulation associated with cell therapy in the process of cutaneous regeneration in third degree burns in rats.

Due to the complexity involved in the healing process of full thickness burns, the literature looks for alternatives to optimize tissue reconstruction. The objective of this study was to explore the action of photobiomodulation therapy associated with MSCs in the healing process of third degree burns. A total of 96 male Wistar rats were used, distributed in four groups with 24 animals each: Control Group, Laser Group, Cell Therapy Group, and Laser Group and Cell Therapy. The burn was performed with aluminum plate (150 °C). We performed analysis of wound contraction, histology, immunohistochemistry, birefringence analysis, and immunoenzymatic assay to evaluate tissue quality. Our results demonstrate that the association of the techniques is able to accelerate the repair process, modulating the inflammatory process, presenting a cutaneous tissue with better quality. Thus, we conclude that the use of photobiomodulation therapy associated with cell therapy is a promising treatment in the repair of total thickness burns.

Marine spongin incorporation into Biosilicate® for tissue engineering applications: An in vivo study.

Biomaterials and bone grafts, with the ability of stimulating tissue growth and bone consolidation, have been emerging as very promising strategies to treat bone fractures. Despite its well-known positive effects of biosilicate (BS) on osteogenesis, its use as bone grafts in critical situations such as bone defects of high dimensions or in non-consolidated fractures may not be sufficient to stimulate tissue repair. Consequently, several approaches have been explored to improve the bioactivity of BS. A promising strategy to reach this aim is the inclusion of an organic part, such as collagen, in order to mimic bone structure. Thus, the present study investigated the biological effects of marine spongin (SPG)-enriched BS composites on the process of healing, using a critical experimental model of cranial bone defect in rats. Histopathological and immunohistochemistry analyzes were performed after two and six weeks of implantation to investigate the effects of the material on bone repair (supplemental material-graphical abstract). Histological analysis demonstrated that for both BS and BS/SPG, similar findings were observed, with signs of material degradation, the presence of granulation tissue along the defect area and newly formed bone into the area of the defect. Additionally, histomorphometry showed that the control group presented higher values for Ob.S/BS (%) and for N.Ob/T.Ar (mm2) (six weeks post-surgery) compared to BS/SPG and higher values of N.Ob/T.Ar (mm2) compared to BS (two weeks post-surgery). Moreover, BS showed higher values for OV/TV (%) compared to BS/SPG (six weeks post-surgery). Also, VEGF immunohistochemistry was increased for BS (two weeks post-surgery) and for BS/SPG (six weeks) compared to CG. TGFb immunostaining was higher for BS compared to CG. The results of this study demonstrated that the BS and BS/SPG scaffolds were biocompatible and able to support bone formation in a critical bone defect in rats. Moreover, an increased VEGF immunostaining was observed in BS/SPG.

Evaluation of the In Vivo Biological Effects of Marine Collagen and Hydroxyapatite Composite in a Tibial Bone Defect Model in Rats.

One of the most promising strategies to improve the biological performance of bone grafts is the combination of different biomaterials. In this context, the aim of this study was to evaluate the effects of the incorporation of marine spongin (SPG) into Hydroxyapatite (HA) for bone tissue engineering proposals. The hypothesis of the current study is that SPG into HA would improve the biocompatibility of material and would have a positive stimulus into bone formation. Thus, HA and HA/SPG materials were produced and scanning electron microscopy (SEM) analysis was performed to characterize the samples. Also, in order to evaluate the in vivo tissue response, samples were implanted into a tibial bone defect in rats. Histopathological, immunohistochemistry, and biomechanical analyses were performed after 2 and 6 weeks of implantation to investigate the effects of the material on bone repair. The histological analysis demonstrated that composite presented an accelerated material degradation and enhanced newly bone formation. Additionally, histomorphometry analysis showed higher values of %BV/TV and N.Ob/T.Ar for HA/SPG. Runx-2 immunolabeling was higher for the composite group and no difference was found for VEGF. Moreover, the biomechanical analysis demonstrated similar values for all groups. These results indicated the potential of SPG to be used as an additive to HA to improve the biological performance for bone regeneration applications. However, further long-term studies should be carried out to provide additional information regarding the material degradation and bone regeneration.