Collagen Bundles Research Articles

Ultrastructure and immunohistochemistry of apteric skin in ratites and its epidermal soft cornification

An electron microscopy and immunohistochemistry study has been conducted to acquire comparative information on the structure of apteric skin in ratites, ostrich and emu. The epidermis is thin in the neck of both species and thicker in the dorsal region where acidic and neutral keratins are present in the viable epidermis and stratum corneum. The dermis in both species is mostly occupied by collagen fibrils that form large bundles, often organized in alternated layers in the deeper part of the dermis. Numerous collagen fibrils contact the basement membrane of the epidermis. Sparse tactile Meissner or Krause sensilli are present among the thick collagen bundles. The ostrich epidermis in the dorsal skin is thicker than in the neck, with a columnar basal layer, 3–5 intermediate suprabasal layers and a thick corneous layer. The epidermis of the neck in emu is very thin, featuring two-three narrow cell layers above a flat basal layer and a relatively thick corneous layer. Basal and suprabasal keratinocytes contain lipid droplets and small keratin bundles but no keratohyalin accumulates in pre-corneous cells. The thin corneocytes form a multilayered corneous layer. Loricrine is present in pre-corneous and corneous layers while CBPs, formerly indicated as beta-keratins, are absent in apteric epidermis.

Ultrastructural Characterization of Testis in Non-descript Goat (Capra hircus)

Background: The proposed experiment was aimed at locating the spermatogonial stem cell niches inside the testis and to characterise the development of germ cells of testis in the non- descript goats at the different stages of pre and post natal life, which could be useful in selecting the goats for breeding at appropriate time and for other interventions related to reproductive developments in the goats. Methods: The present study was conducted on the testes of non-descript goats divided into three groups, viz. neonatal (within 1 month), prepubertal (from 1-18 months) and pubertal (above 18 months) with 10 healthy animals in each group. The collected samples of testis were processed for scanning electron microscopic study and subsequently, the samples were viewed and the photographs were taken in the facility available at Central Instrumentation Facility (CIF), OUAT, Bhubaneswar. Result: The present study revealed that the testis was surrounded by the tunica albuginea, a thin capsule of connective tissue, from which thin septum originated and extended into the inside of the organ. Among these septa, the seminiferous tubules were found. The seminiferous epithelium consisted of spermatogonial cells at different stages of development separated from each other by interstitial connective tissue. The interstitium was made up of randomly arranged collagen bundles. The intertubular vascular connective tissue contained Leydig cells mainly at wider locations where they were bounded by more than two seminiferous tubules. The mediastinal rete testis area contained many cavities of many intercommunicating channels supported by connective tissue pillars. The present study helped in developing a baseline data on the ultrastructural characteristics of seminiferous epithelium, rete restis, peritubular cells, Lyedig cells and other components of testis in non-descript goat at different post natal stages under study. The appearance of seprmatogonial cell lineage at the various post natal stages in non-descript goat would help in accessing the reproductive status of the animal.

Activatable Near-Infrared Fluorescence Probe for Hypochlorous Acid Detection in Early Diagnosis of Keloids.

Keloids represent pathologic conditions characterized by the presence of hyalinized collagen bundles and chronic inflammatory reactions. Recently, increased ROS production and disrupted apoptosis mechanisms in keloids have been reported, although the detailed mechanisms remain unclear. Herein, we developed a specific fluorescence probe, Pro-NBS, to investigate ClO- levels in keloids. The probe demonstrated high specificity for ClO- over other ROS and exhibited a strong linear detection relationship. Based on its performance, we focused on the TGF-β pathway in the development of keloids. ROS upregulation was observed in keloid-derived fibroblasts. Using ClO- as an intrinsic overexpression marker, our probe effectively distinguished between normal fibroblasts and keloid-derived fibroblasts both in vitro and in vivo. Furthermore, Pro-NBS showed potential for monitoring the progression and evaluating the systematic therapy of abnormal scarring or keloids.

Organization, density, and content of collagen in the body wall of sea cucumbers Acaudina rosettis and Phyllophorus sp.

Marine collagen has been known to have lower immunogenicity compared to bovine collagen. The primary component in the body wall of sea cucumbers is collagen. This study aimed to investigate the density, bundle organization, and yield of collagen in the two sea cucumber species, Acaudina rosettis and Phyllophorus sp. collected from the Madura Strait, Indonesia. The body wall parts, including the dorsal anterior, dorsal median, dorsal posterior, ventral anterior, ventral median, and ventral posterior, from five samples of each species, were fixed and decalcified. They were histologically processed using the paraffin method before staining them with Van Gieson to visualize collagen in the cross-sections of body wall tissue. Collagen density was determined using the ImageJ software, while collagen bundle organization was examined negatively by utilizing the image editing application. Collagen density data were analyzed using repeated-measures ANOVA (α = 0.05). Collagen content in the body wall of each species was examined using acid solubilization-based collagen extraction, which did not significantly differ between different parts of the body wall in each species (p = 0.161 for A. rosettis, p = 0.095 for Phyllophorus sp.). However, Phyllophorus sp. exhibited a higher collagen density and collagen bundles, which were larger and more organized compared to A. rosettis. The collagen content was higher in A. rosettis (10.07%) compared to Phyllophorus sp. (8.07%). Further study can be performed to explore the potential of collagen from these sea cucumber species for commercial use.

Morphological verification of the effects of dynamic quadripolar radio frequency in patients of reproductive age with pelvic organ prolapse

Background. Pelvic organ prolapse is a common pathology that has a significant impact on women’s quality of life. According to literature data, 30% of women of reproductive age have symptomatic forms of pelvic organ prolapse (POP). 13% of patients undergo surgical treatment of POP. However, some patients again complain about the symptoms of genital prolapse, despite the surgical correction.Objective. To evaluate the effect of dynamic quadripolar radio frequency on the histological picture of the vaginal mucosa in patients of reproductive age with pelvic organ prolapse.Materials and methods. A prospective comparative study was conducted, which included 38 patients of reproductive age. The patients were randomized and divided into 2 groups 2 months before the surgical treatment of POP. The first group (n=17) of patients underwent preoperative preparation using dynamic quadripolar radio frequency (DQRF) before surgical treatment. The second group (n=21) did not undergo preoperative preparation. Both groups of women received surgical treatment in volume — plastic surgery of genital prolapse with their own tissues. A biopsy of the vaginal mucosa was obtained intraoperatively, and its histological assessment was performed. The material was stained with hematoxylin-eosin, light microscopy was performed using an Axioplan 2 microscope (CarlZeissJena, Germany).Results. Increased vascularization of the vaginal mucosa, absence of signs of inflammation and fibrosis, and ordering of collagen bundles were noted in patients who underwent preoperative preparation using DQRF.Conclusion. Changes in the histological picture of the vaginal mucosa after the use of DQRF indicate an increased regenerative ability of tissues, which may be a predictor of better healing after surgical treatment and may affect the long-term results of surgical treatment.

A novel model of post-burn hypertrophic scarring in rat tail with a high success rate and simple methodology

BackgroundHypertrophic scars present a serious concern after surgeries and trauma, particularly with the highest risk following burn injury. The current modeling methods usually involve relatively complicated surgical operations and special equipment, and have unstable reproducibility and reliability. This study aimed to establish a simple and reliable model of post-burn hypertrophic scarring in the rat tail. MethodsWet gauze saturated with hot water (94–98 °C) was applied to the dorsal side of the rat tail for varying durations to induce burn injury. Wounds were left exposed until completely healed, and the optimal duration for scalding treatment was determined based on gross examination. Thereafter, the optimal scalding duration was used again to evaluate scar formation over time, which was tracked through hematoxylin-eosin (HE) and Masson staining, immunohistochemistry of scar-related proteins and number/distribution of vascular endothelial cells, and picrosirius red staining to measure the quantities and proportion of type I and III collagen. ResultsThe scalding duration which led to optimal post-burn scarring was 15 s, with an overall success rate of 87.5 %. Complete healing of the wound occurred after roughly 30 days, leading to the formation of scars grossly red in appearance, tough to the touch and raised compared to the surrounding skin. Microscopically, the epidermis and dermis of the scar were significantly thicker than normal rat tail skin, and the dermis of scar contained a large number of disorganized bundles of fine filamentous collagen. We also observed a significant increase in the number of TGF-β1-positive cells and capillaries in the dermis (p < 0.05). Picrosirius red staining showed that compared to type III collagen, the expression of type I collagen was more dominant in scar tissue, and was more finely distributed than in normal rat tail skin. ConclusionWe successfully established a model for post-burn hypertrophic scarring, utilizing reliable and simple techniques and materials, which could simulate the biological characteristics of post-burn scarring. Our innovative model has the potential to facilitate the study of post-burn wound healing and scar formation.

Enhancing wound healing in cattle through the application of vitreous humour fluid and platelet-rich plasma

The aim of this work: to examine the impact of applying vitreous humour fluid as well as platelet-rich plasma (PRP) on cattle's wound healing. Twelve dairy cows, randomly divided into three groups, constituted the subjects for this research. Those cows consumed standard quantities—grains; alfalfa; straw—with ad libitum clean water. We collected Vitreous humour fluid from slaughtered cows, storing it at 4°C. Through withdrawing blood from the same cows and separating PRP from plasma, we prepared Autologous PRP. Furthermore, we prepared a mixture of PRP with vitreous humour fluid which has been subsequently applied to wound site. At 7, 14, and 21 weeks, we performed biopsies on the cows for histopathological examination. On day 7, the histopathological examination revealed improved tissue reorganization and proliferation in wounds treated with PRP and vitreous humour fluid. Furthermore, in comparison with the control group--at this same time point--collagen organization has been notably superior. Moving onto day 14: a complete or partial union of wound margins manifested in the two groups treated with PRP and vitreous humour fluid; also, better granulation tissue formation stood out significantly—an indicator that healing progress had been robustly effective. By day 21; complete epithelialization—alongside dense collagen bundles filling the wound site—signified successful healing of wounds treated specifically with the use of vitreous humor fluid. The findings of the presented work indicate that the utilization of vitreous humour fluid and PRP could facilitate the process of wound healing in cattle. Improvements in tissue reorganization, proliferation, and collagen organization were all found. In the process of developing wound healing therapies for cattle, such findings offer useful insights that can be further developed.

Linear podosomes display low Cdc42 activity for proplatelet elongation by megakaryocytes

Blood platelets result from differentiation of megakaryocytes (MKs) into the bone marrow. It culminates with the extension of proplatelets (PPT) through medullar sinusoids and release of platelets in the blood stream. Those processes are regulated by contact with the microenvironment mediated by podosomes. We previously demonstrated that contact of megakaryocytes to Collagen I fibers initiated the formation of linear podosomes required for proplatelets extension and release of mature platelets. MKs linear podosomes have the particularity of displaying mechanical pulling activity but, unlike other linear podosomes, they lack the ability of digesting the extracellular matrix (ECM), as we recently demonstrated. The Cdc42 small GTPase is required for actomyosin-dependent maturation of the demarcation membrane system (DMS), a membrane reservoir for PPT and platelets components. Cdc42 is a known protein of the podosomes core, and is instrumental to accurate platelets release into the sinusoids. Indeed, FRET analysis showed that Cdc42 activity was very high and central to DMS formation. Unexpectedly, even though we found the protein in linear podosomes, almost undetectable Cdc42 activity was detected in those structures. This observation suggests that Cdc42 could also act as scaffold to assemble proteins required for PPT formation/elongation along Collagen I fibers in MKs. Eventually, we demonstrated that linear podosomes appear as points of contact between Collagen I fibers and DMS membranes, to mechanically extend PPT along Collagen bundles, independently of Cdc42 activity.

Case report: Reactive granulomatous dermatitis presenting with inguinal erythematous plaques in a patient administered with pravastatin

An identical group of disorders has been called “interstitial granulomatous dermatitis” and “palisaded neutrophilic and granulomatous dermatitis.” In addition, a drug-induced subset of this condition has been named “interstitial granulomatous drug reaction (IGDR).” More recently, “reactive granulomatous dermatitis (RGD)” has been proposed as an umbrella term encompassing these three disorders. A considerable number of RGD cases are associated with systemic conditions, including autoimmune diseases, such as rheumatoid arthritis and systemic lupus erythematosus, inflammatory bowel disease, and malignancies. IGDR has also been shown to be caused by certain medications. We present a case of a 74-year-old Japanese man showing an asymptomatic, well-demarcated erythema eruption on the bilateral inguinal region extending to the lower abdomen and proximal thigh area. He had hyperlipidemia and had been taking pravastatin for 4 years. A biopsy specimen taken from the erythematous lesion revealed infiltration of lymphocytes and histiocytes in the upper and lower dermis. Interstitial infiltrates of histiocytes and lymphocytes were found as they were dispersed between collagen bundles. Immunostaining showed CD68+ macrophages intermingled with CD4+ and CD8+ T cells. Based on the clinical and histologic findings, the eruption was diagnosed as RGD. Because of the possibility of IGDR, pravastatin was stopped. His eruption completely disappeared within 6 months after the discontinuation. The list of drugs that cause RGD includes angiotensin-converting enzyme inhibitors, antihistamines, β-blockers, antidepressants, anticonvulsants, tocilizumab and ustekinumab. In addition, various statins have been reported to induce drug eruptions. The eruption types are mainly eczematous or lichenoid reactions, with psoriasiform or ichthyosiform reactions occurring rarely. There was only one report documenting that RGD occurred in patients administered rosuvastatin, with annular, violaceous plaques distributed on the extremities, proximal trunk and intertriginous areas. Pravastatin induces lichenoid eruption, but RGD has not been documented. Our case suggests that RGD is underestimated as an adverse effect of statins possibly because of its unusual cutaneous manifestations.

Functional morphology of the pharyngeal teeth of the ocean sunfish, Mola mola.

Many fish use a set of pharyngeal jaws in their throat to aid in prey capture and processing, particularly of large or complex prey. In this study-combining dissection, CT scanning, histology, and performance testing-we demonstrate a novel use of pharyngeal teeth in the ocean sunfish (Mola mola), a species for which pharyngeal jaw anatomy had not been described. We show that sunfish possesses only dorsal pharyngeal jaws where, in contrast to their beaklike oral teeth, teeth are recurved spikes, arranged in three loosely connected rows. Fang-like pharyngeal teeth were tightly socketed in the skeletal tissue, with shorter, incompletely-formed teeth erupting between, suggesting tooth replacement. Trichrome staining revealed teeth anchored into their sockets via a combination of collagen bundles originating from the jaw connective tissue and mineralized trabeculae extending from the teeth bases. In resting position, teeth are nearly covered by soft tissue; however, manipulation of a straplike muscle, running transversely on the dorsal jaw face, everted teeth like a cat's claws. Adult sunfish suction feed almost exclusively on gelatinous prey (e.g., jellyfish) and have been observed to jet water during feeding and other activities; flume experiments simulating jetting behavior demonstrated adult teeth caught simulated gelatinous prey with 70%-100% success, with the teeth immobile in their sockets, even at 50x the jetting force, demonstrating high safety factor. We propose that sunfish pharyngeal teeth function as an efficient retention cage for mechanically challenging prey, a curious evolutionary convergence with the throat spikes of divergent taxa that employ spitting and jetting.

Thyroid hemiatrophy associated with papillary thyroid carcinoma.

The present study aimed to investigate CT imaging features, pathological findings, and prognosis in patients with thyroid hemiatrophy (THA) associated with papillary thyroid carcinoma (PTC). This retrospective study included 225 patients with histopathologically proven PTC treated by surgical resection who underwent preoperative CT scanning. On CT images, THA was defined as thyroid parenchymal hemiatrophy on the ipsilateral side of PTC. CT findings, overall survival, and disease-free survival were compared between patients with and without THA. Pathological findings were also assessed in PTCs with and without THA. THA was observed in 35 of 225 (16%) patients with PTC. Atrophic thyroid parenchyma was observed in the right lobe of 20 patients (57%) and in the left lobe of the remaining 15 patients (43%). With respect to the solid components within PTCs, contrast-enhanced CT attenuation (114.2 ± 18.2 vs. 126.7 ± 31.3 HU; p < 0.05) and CT attenuation change for contrast-enhanced CT minus unenhanced CT (60.2 ± 18.1 vs. 72.3 ± 31.0 HU; p < 0.05) were significantly lower in PTCs with THA than in those without THA. Histopathologically, almost all PTCs with THA (97%) had keloid-like collagen, which is broad bundles of hypocellular collagen with bright eosinophilic hyalinization, typically observed in keloid. However, no significant differences were observed in the prognosis between the two groups. THA was occasionally observed in patients with PTC. Weak contrast-enhancement was distinct characteristic of PTC patients with THA, which is probably caused by keloid-like collagen.

A Comparative Analysis of the Advances in Scar Reduction: Techniques, Technologies, and Efficacy in Plastic Surgery.

The study provides a comprehensive analysis of the latest methodologies and treatments aimed at improving scar management. Scar formation results from the replacement of normal skin with fibroblasts, leading to a structured unidirectional collagen bundle, as opposed to the collagen sheet matrix found in healthy skin. This review categorizes scars into hypertrophic scars and keloids, each with distinct pathophysiological characteristics. It highlights the importance of consistent scar assessment using scales such as the Vancouver Scar Scale and the Patient and Observer Scar Assessment Scale, emphasizing the need for standardized evaluation methods. The study systematically reviews various scar management techniques, ranging from traditional surgical methods to innovative treatments. Conventional approaches such as pressure garments and silicone gel sheeting are explored, noting their roles in maintaining hydration and occlusion. The efficacy of intralesional corticosteroid injections and laser therapies is discussed, with particular attention given to their combined use for optimal outcomes. The review also covers advanced techniques such as microneedling, platelet-rich plasma therapy, and stem cell-based treatments, detailing their mechanisms and potential benefits in scar remodelling. Additionally, the study underscores the emerging role of botulinum toxin A in both preventive and corrective scar treatments, offering promising results in reducing movement-induced scar exaggeration. The systematic review includes a thorough examination of existing literature, clinical trials, and meta-analyses to evaluate the effectiveness of these interventions. It concludes by calling for further research to refine these techniques and enhance their application in clinical practice, aiming to achieve better aesthetic and functional outcomes for patients with scars.

Idiopathic hyalinizing fibrosclerosis: A systemic steroid-resistant condition distinct from IgG4-related disease

Since the concept of IgG4-related disease (IgG4-RD) was proposed, that diagnosis has been considered in idiopathic fibroinflammatory diseases in various organs, particularly in cases with multi-organ involvement. We have recently encountered three cases of fibrosing disease of uncertain etiology with shared microscopic appearances. Case 1 (56-year-old man) had an irregular mass at the base of mesentery. Case 2 (29-year-old woman) presented with obstructive jaundice due to an ill-defined mass at the hepatic hilum and two lung nodules. Case 3 (53-year-old man) had multiple solid nodules in the mediastinum, peritoneum, retroperitoneum, and mesentery; he also had diffuse irregular narrowing of the intra- and extra-hepatic bile ducts in keeping with sclerosing cholangitis. Serum IgG4 concentrations were not elevated. Biopsies from the nodular lesions showed extensive hyalinizing fibrosis with an only focal lymphoplasmacytic infiltrate. Thick collagenous bundles are arranged in an irregular or partly whorl pattern. Typical storiform fibrosis or obliterative phlebitis was not observed. The number of IgG4-positive plasma cells was <10 cells/high-power field; the ratio of IgG4/IgG-positive plasma cells was <30%. After the histological diagnosis of sclerosing mesenteritis, pulmonary hyalinizing granuloma, and mediastinal fibrosis was made, they were treated with a trial of steroids, but none showed a significant response. In conclusion, a hyalinizing fibrotic condition can occur at various anatomical sites. They have shared microscopic findings, and are steroid-resistant. Although the clinical presentation may mimic IgG4-RD, the two conditions are likely distinct. We would propose a diagnostic term of ‘idiopathic hyalinizing fibrosclerosis’ for this under-recognized, rare, systemic condition.

TGFβ-mediated inhibition of hypodermal adipocyte progenitor differentiation promotes wound-induced skin fibrosis.

Aberrant activation of dermal fibroblasts during wound healing often leads to debilitating fibrotic changes in the skin, such as scleroderma and keloids. However, the underlying cellular and molecular mechanisms remain elusive. Here, we established a wound-induced skin fibrosis (WISF) mouse model in mature adult mice, characterised by excessive deposition of collagen bundles, loss of dermal adipocytes, and enrichment of DPP4+Ly6A+THY1+ hypodermal interstitial adipocyte progenitors (HI-APs) and pericytes, resembling human fibrotic skin diseases. This WISF model exhibited an age-dependent gain of fibrotic characteristics, contrasting with the wound-induced hair neogenesis observed in younger mice. Through comprehensive analyses of the WISF, we delineated a trajectory of fibroblast differentiation that originates from HI-APs. These progenitors highly expressed several extracellular matrix (ECM) genes and exhibited a TGFβ pathway signature. TGFβ was identified as the key signal to inhibit the adipogenic potential and maintain the fibrogenic potential of dermal APs. Additionally, administering a TGFβ receptor inhibitor to wound scar reduced the abundance of ECM-producing APs. Finally, analysis of human scleroderma skin tissues revealed a negative correlation between the expression of AP-, ECM-, and TGFβ pathway-related genes and PPARG. Overall, this study establishes a wound-induced skin fibrosis mouse model and demonstrates that TGFβ-mediated blockage of HI-AP differentiation is crucial for driving fibrotic pathology. Targeting HI-APs and adipogenesis may provide novel avenues for developing disease-modifying therapies for fibrotic skin diseases.

Analysis of stress response distribution in patients with lateral ankle ligament injuries: a study of neural control strategies utilizing predictive computing models.

Ankle sprains are prevalent in sports, often causing complex injuries to the lateral ligaments. Among these, anterior talofibular ligament (ATFL) injuries constitute 85%, and calcaneofibular ligament (CFL) injuries comprise 35%. Despite conservative treatment, some ankle sprain patients develop chronic lateral ankle instability (CLAI). Thus, this study aimed to investigate stress response and neural control alterations during landing in lateral ankle ligament injury patients. This study recruited twenty individuals from a Healthy group and twenty CLAI patients performed a landing task using relevant instruments to collect biomechanical data. The study constructed a finite element (FE) foot model to examine stress responses in the presence of laxity of the lateral ankle ligaments. The lateral ankle ligament was modeled as a hyperelastic composite structure with a refined representation of collagen bundles and ligament laxity was simulated by adjusting material parameters. Finally, the validity of the finite element model is verified by a high-speed dual fluoroscopic imaging system (DFIS). CLAI patients exhibited earlier Vastus medialis (p < 0.001) and tibialis anterior (p < 0.001) muscle activation during landing. The FE analysis revealed that with laxity in the ATFL, the peak von Mises stress in the fifth metatarsal was 20.74MPa, while with laxity in the CFL, it was 17.52MPa. However, when both ligaments were relaxed simultaneously, the peak von Mises stress surged to 21.93MPa. When the ATFL exhibits laxity, the CFL is subjected to a higher stress of 3.84MPa. Conversely, when the CFL displays laxity, the ATFL experiences a peak von Mises stress of 2.34MPa. This study found that changes in the laxity of the ATFL and the CFL are linked to shifts in metatarsal stress levels, potentially affecting ankle joint stability. These alterations may contribute to the progression towards CLAI in individuals with posterolateral ankle ligament injuries. Additionally, significant muscle activation pattern changes were observed in CLAI patients, suggesting altered neural control strategies post-ankle ligament injury.

Intermediate filaments spatially organize intracellular nanostructures to produce the bright structural blue of ribbontail stingrays across ontogeny.

In animals, pigments but also nanostructures determine skin coloration, and many shades are produced by combining both mechanisms. Recently, we discovered a new mechanism for blue coloration in the ribbontail stingray Taeniura lymma, a species with electric blue spots on its yellow-brown skin. Here, we characterize finescale differences in cell composition and architecture distinguishing blue from non-blue regions, the first description of elasmobranch chromatophores and the nanostructures responsible for the stingray's novel structural blue, contrasting with other known mechanisms for making nature's rarest color. In blue regions, the upper dermis comprised a layer of chromatophore units -iridophores and melanophores entwined in compact clusters framed by collagen bundles- this structural stability perhaps the root of the skin color's robustness. Stingray iridophores were notably different from other vertebrate light-reflecting cells in having numerous fingerlike processes, which surrounded nearby melanophores like fists clenching a black stone. Iridophores contained spherical iridosomes enclosing guanine nanocrystals, suspended in a 3D quasi-order, linked by a cytoskeleton of intermediate filaments. We argue that intermediate filaments form a structural scaffold with a distinct optical role, providing the iridosome spacing critical to produce the blue color. In contrast, black-pigmented melanosomes within melanophores showed space-efficient packing, consistent with their hypothesized role as broadband-absorbers for enhancing blue color saturation. The chromatophore layer's ultrastructure was similar in juvenile and adult animals, indicating that skin color and perhaps its ecological role are likely consistent through ontogeny. In non-blue areas, iridophores were replaced by pale cells, resembling iridophores in some morphological and nanoscale features, but lacking guanine crystals, suggesting that the cell types arise from a common progenitor cell. The particular cellular associations and structural interactions we demonstrate in stingray skin suggest that pigment cells induce differentiation in the progenitor cells of iridophores, and that some features driving color production may be shared with bony fishes, although the lineages diverged hundreds of millions of years ago and the iridophores themselves differ drastically.

The Role of Vitamin A on the Histology of Skin of Adult Rats After Eposure to UVB

Background: long-term eposure of skin to sun (UV light) may produce different dermatological changes. The aim of this eperiment is to eplore the protective effects of oral vitamin A on skin subjected to UVB. Methods: twenty rats were separated into: group 1 (without UVB eposure), group 2 (eposed to single daily increasing dose of UVB for one week), group 3 (eposed to UVB with oral daily administration of vit A 10000 IU for one week), group 4 (received vit A for one week). The daily doses of UVB were respectively 0.24, 0.36, 0.48, 0.6, 0.72, 0.84 and 0.96 J/cm2. Skin samples were stained with hematoylin-eosin and Masson’s trichrome stains, in addition to Melan-A stain for melanocytes. Results: histopathological results in skin of group 2 demonstrated loss of normal architecture with increase in thickness of epidermis, hyperkeratosis and parakeratosis, moreover, skin sections detected increased number of inflammatory cells with damaged hair follicles. The basal layer shows an increase in mitotic division and necrosis, besides, epidermal edema and vascular congestion. Furthermore, collagen fibers were degraded. Immunohistochemical reaction revealed intense positive epression of Melan-A with increased proliferation and activity of melanocytes, while sections of groups 1 and 4 show normal healthy skin and negative Melan-A epression. In contrast, skin of group 3 reveals mild hyperkeratosis with normal keratin layer, in addition, the infiltration of inflammatory cells was dropped and hair follicles were preserved. Collagen bundles were slightly degraded with normal arrangement. Immunohistochemical results of this group show mild positive epression of Melan A. Conclusion: oral administration of vitamin A decreases the toic effect of UVB radiation on skin and reduces its induced pigmentation.

Tissue Regeneration in Infected Wounds of Albino Rats Using Ciprofloxacin-Loaded Gelatin Microspheres Incorporated Collagen Scaffold: A Histological Approach with H&amp;E Staining

A wound care system consisting of ciprofloxacin-loaded gelatin microspheres impregnated in a macroporous collagen scaffold was created to effectively control wound infection and regenerate soft tissue at the wound site. Histological and biochemical alterations were observed in infected wounds treated with these scaffolds in Albino Wistar rats. Furthermore, the study examined the immediate and prolonged release of ciprofloxacin from the scaffolds, as well as their function in eliminating bacterial infections and expediting the process of skin healing and regeneration. The developed technique was followed in the streamlined process of creating these collagen scaffolds. Compared to untreated wounds, the group receiving scaffold treatment experienced a faster rate of wound closure. It was noted that the rate of infections was considerably reduced and that full soft tissue regeneration occurred within 12 days. The development of well-deposited collagen bundles in the treated groups was demonstrated by H&amp;E staining, which verified the flawless regeneration of the dermis and epidermis. The antimicrobial agent-loaded gelatin microspheres impregnated into the porous collagen scaffold demonstrated remarkable soft tissue regeneration and efficient infection control at the wound site.

The Protective Effects of Silkworm (Bombyx mori) Pupae Peptides on UV-Induced Skin Photoaging in Mice.

Silkworm (Bombyx mori) pupae are popular edible insects with high nutritional and therapeutic value. Currently, there is growing interest in the comprehensive application of silkworm pupae. In this study, peptides that exhibited anti-photoaging activity were obtained from silkworm pupae protein, aiming to investigate the protective effects and potential mechanisms of silkworm pupae peptides (SPPs) on skin photoaging. The results showed that SPPs were composed of 900 short peptides and could effectively alleviate skin photoaging progression. They significantly eliminated excessive production of ROS and MDA; meanwhile, they also renovated the antioxidant enzyme activities. The biomarkers related to collagen synthesis and degradation, including hydroxyproline, interstitial collagenase, and gelatinase, demonstrated that SPPs could suppress collagen degradation. Histopathological results showed that SPPs could reduce the inflammatory infiltrate and the thickness of the dermis and epidermis, as well as increase the collagen bundles and muscle fibers. The histopathological and biochemical results confirmed that SPPs could alleviate photoaging by inhibiting abnormal skin changes, reducing oxidative stress, and immune suppression. Overall, these data prove the protective effects of SPPs against the photoaging process, suggesting their potential as an active ingredient in skin photoaging prevention and therapy.

Contactless magnetically responsive injectable hydrogel for aligned tissue regeneration

Cellular alignment plays a pivotal role in several human tissues, including skeletal muscle, spinal cord and tendon. Various techniques have been developed to control cellular alignment using 3D biomaterials. However, the majority of 3D-aligned scaffolds require invasive surgery for implantation. In contrast, injectable hydrogels provide a non-invasive delivery method, gaining considerable attention for the treatment of diverse conditions, including osteochondral lesions, volumetric muscle loss, and traumatic brain injury.We engineered a biomimetic hydrogel with magnetic responsiveness by combining gellan gum, hyaluronic acid, collagen, and magnetic nanoparticles (MNPs). Collagen type I was paired with MNPs to form magnetic collagen bundles (MCollB), allowing the orientation control of these bundles within the hydrogel matrix through the application of a remote low-intensity magnetic field. This resulted in the creation of an anisotropic architecture. The hydrogel mechanical properties were comparable to those of human soft tissues, such as skeletal muscle, and proof of the aligned hydrogel concept was demonstrated.In vitro findings confirmed the absence of toxicity and pro-inflammatory effects. Notably, an increased fibroblast cell proliferation and pro-regenerative activation of macrophages were observed. The in-vivo study further validated the hydrogel biocompatibility and demonstrated the feasibility of injection with rapid in situ gelation. Consequently, this magnetically controlled injectable hydrogel exhibits significant promise as a minimally invasive, rapid gelling and effective treatment for regenerating various aligned human tissues.