Morphological analysis of patchy thickening and reddish discoloration of active hair growth areas in the skin of New Zealand White rabbits

Ishihara, Tomoko; Yamashita, Haruhiro; Sakurai, Takanobu; Morita, Junya; Sakamoto, Kouji; Ishii, Aiko; Sasaki, Masahiro

doi:10.1293/tox.2017-0033

Cited by 7 publications

(4 citation statements)

References 15 publications

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“…During the anagen phase, hair follicles grow rapidly by cell proliferation and reach their longest length. After regression by apoptosis in the catagen phase, they enter the telogen phase [10, 11]. Apoptosis is a critical event in the regulation of the hair cycle as anagen hairs normally grow for 4–7 years in humans before the cycle enters into the resting phases of catagen and telogen [12, 13].…”

Section: Introductionmentioning

confidence: 99%

Analyses of histological and transcriptome differences in the skin of short-hair and long-hair rabbits

et al. 2019

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Background: Hair fibre length is an important economic trait of rabbits in fur production. However, molecular mechanisms regulating rabbit hair growth have remained elusive. Results: Here we aimed to characterise the skin traits and gene expression profiles of short-hair and long-hair rabbits by histological and transcriptome analyses. Haematoxylin-eosin staining was performed to observe the histological structure of the skin of short-hair and long-hair rabbits. Compared to that in short-hair rabbits, a significantly longer anagen phase was observed in long-hair rabbits. In addition, by RNA sequencing, we identified 951 genes that were expressed at significantly different levels in the skin of short-hair and long-hair rabbits. Nine significantly differentially expressed genes were validated by quantitative real-time polymerase chain reaction. A gene ontology analysis revealed that epidermis development, hair follicle development, and lipid metabolic process were significantly enriched. Further, we identified potential functional genes regulating follicle development, lipid metabolic, and apoptosis as well as important pathways including extracellular matrix-receptor interaction and basal cell carcinoma pathway. Conclusions:The present study provides transcriptome evidence for the differences in hair growth between shorthair and long-hair rabbits and reveals that lipid metabolism and apoptosis might constitute major factors contributing to hair length.

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Section: Introductionmentioning

confidence: 99%

Analyses of histological and transcriptome differences in the skin of short-hair and long-hair rabbits

et al. 2019

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“…Rabbits are highly sensitive to skin irritation and are easy to feed in the laboratory. Thus, rabbits are widely used in skin penetration studies to predict human skin irritation and determine the safety 30. The results of the skin irritation study listed in Table 1 indicated that the skin of New Zealand rabbits were not allergic to the Tβ-4 ethosomal gel, Tβ-4 gel, and the blank gel after 24 h of application and 7 days of repeated applications.…”

Section: Resultsmentioning

confidence: 99%

<p>Ethosomal Gel for Improving Transdermal Delivery of Thymosin β-4</p>

Fu¹,

Shi²,

Wang³

et al. 2019

IJN

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PurposeThymosin β-4(Tβ-4) is a macromolecular protein drug with potential for drug development in wound repair but is limited by the shortcomings of macromolecular protein, such as large volumes, poor membrane permeability, and unstable physicochemical characteristics. Ethosomes could enhance cell membrane fluidity and reduce epidermal membrane density to make macromolecular drugs through the stratum corneum into the deeper layers of the skin easily. Herein, we developed and characterized a novel transdermal delivery vehicle to load macromolecular protein peptides and use Tβ-4 as a model drug wrapped into ethosomes.MethodsWe used the orthogonal method to optimize the formulation of the ethosome preparation prepared by the ethonal infusion method. Ethosomal gels were characterized by using different analytical methods. Transdermal release rate in vitro have been demonstrated in Franz diffusion cells and the efficacy of drug-loaded nanocarriers in vivo was investigated in a mouse model.ResultsOptimized Tβ-4 ethosomal gels have good physicochemical properties. The drug amounts of the cumulative release in the ethosomal gel within 5 hours were 1.67 times that of the T-β4 gel in vitro release study, and the wound healing time of ethosomal gel group was only half of the T-β4 gel group in vivo pharmacokinetic study. Compared with the free drug group, the ethosome preparation not only promotes the percutaneous absorption process of the macromolecular protein drugs but also shortened wound recovery time.ConclusionHence, we provide a possible good design for ethosomal gel system that can load macromolecular protein peptide drugs to achieve transdermal drug administration, promoting the percutaneous absorption of the drug and improving the effect.

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“…Dogs differ from these categories, although hair loss associated with hair cycle arrest is seen 33 , 36 , 37 . Irregular hair spots in rabbits have been reported to appear as raised, thickened islands compared to the surrounding skin 38 . Therefore, attention should be paid to studies that evaluate skin reactions in rabbits.…”

Section: Cutaneous Adnexamentioning

confidence: 99%

Morphological characteristics and notes of the skin in preclinical toxicity assessment

Moroki

2023

J Toxicol Pathol

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In this review, the histological structures of the skin are summarized for fundamental knowledge for toxicological assessment. The skin is composed of epidermis, dermis, subcutaneous tissue, and associated adnexa. In the epidermis, keratinocytes comprise four layers, and three other cell types, besides keratinocytes, play various roles. Epidermal thickness varies with species and body site. In addition, it can be affected by tissue preparation procedures, which can render toxicity assessments difficult. Bulge stem cells are the origin of sebaceous glands, epidermal basal layer, and hair follicle formation, and they play an important role in the maintenance of the basic structure of the skin. Stem cells and appendages formed from stem cells sometimes become toxic targets, and it is useful to study the origins of the hair follicle/hair cycle to interpret their toxicity. Irritant contact dermatitis and allergic contact dermatitis are the main adverse reactions in topical application studies. The mechanism involves direct chemical irritation of the skin, and histologically, epidermal necrosis and accompanying inflammatory cell infiltration. In allergic contact dermatitis, an inflammatory reaction and intercellular or intracellular edema, histologically represented by lymphocytic infiltration of the epidermis and dermis, are observed. Regional and species differences exist in the dermal absorption of compounds, and differences in the thickness of the stratum corneum substantially contribute to these differences. Learning the basic structures, functions, and possible artifacts will contribute to the evaluation of skin toxicity by topical and systemic applications.

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Morphological analysis of patchy thickening and reddish discoloration of active hair growth areas in the skin of New Zealand White rabbits

Cited by 7 publications

References 15 publications

Analyses of histological and transcriptome differences in the skin of short-hair and long-hair rabbits

Analyses of histological and transcriptome differences in the skin of short-hair and long-hair rabbits

<p>Ethosomal Gel for Improving Transdermal Delivery of Thymosin β-4</p>

Morphological characteristics and notes of the skin in preclinical toxicity assessment

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