Oestrogen receptor evaluation in Pomeranian dogs with hair cycle arrest (alopecia X) on melatonin supplementation

The role of oestrogen receptors in dogs with hair cycle arrest (alopecia X) was investigated by immunohistochemistry. The purpose of this study was to determine if hair regrowth in dogs with hair cycle arrest treated with melatonin was associated with a decrease in follicular oestrogen receptors. Fifteen Pomeranians (excluding intact females) with hair cycle arrest were enrolled. Two biopsies were obtained from alopecic areas of the trunk before and after 3 months on melatonin. Haematoxylin and eosin-stained tissues were examined and oestrogen receptor-alpha was demonstrated immunohistochemically. Common histopathological findings included hyperkeratosis, follicular keratosis, excessive tricholemmal keratinization (flame follicles), thin epidermis, few small anagen bulbs, epidermal pigmentation and melanin aggregates within follicular keratin. Melanin aggregates within basal cells and hair were an occasional finding. After 3 months, 40% (six) dogs had mild to moderate hair regrowth. Biopsies from six dogs showed histological evidence of an increase in anagen hairs and eight dogs had a decrease in epidermal pigmentation. Moderate to marked staining intensity of oestrogen receptor-alpha was noted in all sebaceous gland basal cells, all small hair bulbs and follicular epithelium of telogen hairs. There was no oestrogen receptor-alpha staining of nuclei within the epidermis, apocrine glands or dermal fibroblasts. Large anagen hair bulbs had minimal to no oestrogen receptor staining. Hair regrowth was not associated with a change in oestrogen receptor-alpha staining.     

The canine hair cycle - a guide for the assessment of morphological and immunohistochemical criteria

The hair follicle has a lifelong capacity to cycle through recurrent phases of controlled growth (anagen), regression (catagen) and quiescence (telogen), each associated with specific morphological changes. A comprehensive classification scheme is available for mice to distinguish the cycle stages anagen I-VI, catagen I-VIII and telogen. For dogs, such a classification system does not exist, although alopecia associated with hair cycle arrest is common. We applied analogous morphological criteria and various staining techniques to subdivide the canine hair cycle stages to the same extent as has been done in mice. Of all the staining techniques applied, haematoxylin and eosin stain, Sacpic, Masson Fontana and immunohistochemistry for vimentin and laminin proved to be most useful. To evaluate the applicability of our criteria, we investigated skin biopsies from healthy beagle dogs (n=20; biopsies from shoulder and thigh) kept in controlled conditions. From each biopsy, at least 50 hair follicles were assessed. Statistical analysis revealed that 30% of the follicles were in anagen (12% early and 18% late), 8% in catagen (2% early, 5% late and 1% not determinable) and 27% in telogen. Thirty-five per cent of hair follicles could not be assigned to a specific cycle stage because not all follicles within one biopsy were oriented perfectly. In conclusion, this guide will not only be helpful for the investigation of alopecic disorders and possibly their pathogenesis, but may also serve as a basis for research projects in which the comparison of hair cycle stages is essential, e.g. comparative analysis of gene expression patterns.     

Histology of the hair cycle in male beagle dogs

A detailed histologic study of the hair follicles of male Beagle dogs was made to determine changes in microscopic structure associated with the three stages in the hair cycle. Observed changes are that the bulbs of hair follicles in anagen are more closely associated with adipose tissue than they are in telogen. This is due to the deeper penetration of the follicles into the subcutaneous tissue during anagen. The hair germ cells of telogen were presumed to arise from the stratum basale of the matrix cells rather than from the outer root sheath cells. During telogen, the dermal papilla is separated from the club hair, but remains in close proximity to it. There is no connecting stalk as is reported for other animals.     

Comparison of hair follicle histology between horses with pituitary pars intermedia dysfunction and excessive hair growth and normal aged horses

Background –  Pituitary pars intermedia dysfunction (PPID) in older equids is commonly recognized by a long hair coat that fails to shed. Objective –  The aim of this study was to compare hair follicle stages in PPID‐affected horses with excessively long hair coats with the stages of normal aged horses (controls) and to compare hair follicle stages in PPID‐affected horses after 6 months of treatment with pergolide mesylate with those of control horses. Animals –  Eight PPID‐affected horses and four normal, age‐matched, control horses. Methods –  Skin biopsies were collected from the neck and rump of PPID‐affected and control horses. A diagnosis of PPID was established based on hair coat changes and supportive overnight dexamethasone suppression test results. Skin biopsies were repeated after 6 months of treatment with pergolide. The number of hair follicles in anagen (A) or telogen (T) was counted for each skin biopsy using transverse sections. Results –  Pretreatment biopsies had a greater percentage of A follicles (neck 96%, rump 95%) and a lower percentage of T follicles (neck 4%, rump 5%) in PPID‐affected horses than in control horses (A, neck 15%, rump 25%; and T, neck 85%, rump 75%). After treatment with pergolide, all PPID‐affected horses had improved shedding, and the percentages of A follicles (neck 69%, rump 70%) and T follicles (neck 31%, rump 30%) were not different from untreated control horses (A, neck 68%, rump 82%; and T, neck 32%, rump 18%). Conclusions –  These findings document that excessive hair growth (hypertrichosis) in PPID‐affected horses is due to persistence of hair follicles in A. Furthermore, treatment with pergolide improved shedding and reduced the percentage of A follicles in PPID‐affected horses.     

Alopecia areata (pelade) in a cow

A case of alopecia areata (pelade) is described in a cow. Alopecia areata is a rare idiopathic dermatosis of cattle. It is characterized by asymptomatic, solitary or multiple, annular areas of noninflammatory alopecia. Scrapings and cultures are negative, and the diagnosis is confirmed by skin biopsies taken from early lesions, which reveal accumulations of lymphocytes around the bulbs of anagen hair follicles. There is no known effective and practical treatment for affected cattle. The dermatitis is a cosmetic problem, but does not seem to affect general health and production, and spontaneous remission may occur.     

Effects of Photoperiod on Stem Cells Activation in Cashmere Goat Hair Follicles

In order to extend the anagen of cashmere goat hair follicles and increase the production of cashmere,this study was performed with artificially shorten the daylight time among Arbas White cashmere goats. Skin tissue sections from cashmere goats were collected to compare the morphologic changes between artificial daylight and natural daylight,and immunohistochemical method was used to study the hair follicle cell proliferation and important protein expression in related signaling pathways. The results showed that strong cell proliferation occurred in cashmere goat hair follicle cells during artificial daylight,plenty of cytokeratin 15 (K15) positive signals were distributed in the outer root sheath,β-catenin protein was actively expressed in hair matrix and root sheath, indicating that the hair follicles were in the anagen growth phase;Meanwhile,cashmere goat hair follicles under natural daylight were in telogen with weak signals. Above all prove that short photoperiod played an important role in promoting hair follicle growth,the artificial short photoperiod could change hair follicle growth cycle and make hair follicles earlier enter to the anagen growth phase,causing a variety of typical gene expressions during hair follicle growth.     

光周期对于绒山羊毛囊干细胞激活的影响

为了延长绒山羊毛囊兴盛期,提高羊绒产量,本试验通过人工缩短内蒙古阿尔巴斯型绒山羊的日照时间,利用组织切片技术对比人工短光照和自然光照周期下绒山羊皮肤组织形态变化,利用免疫组织化学方法研究毛囊细胞增殖及相关信号通路重要蛋白的表达。结果显示,人工短光照周期下绒山羊毛囊细胞增殖强烈,干细胞标记角蛋白15（cytokeratin 15,K15）阳性信号大量分布于外根鞘,β-catenin信号活跃表达于毛母质及根鞘,毛囊提前进入兴盛期;而自然光照周期下绒山羊毛囊仍停留在休止期,相应蛋白信号表达较弱。综上表明,短日照对毛囊生长具有明显的促进作用,人工短光照周期可以提前激活毛囊干细胞,使其提前进入兴盛期,引起多种毛囊生长相关蛋白的表达。     

Alopecia areata with lymphocytic mural folliculitis affecting the isthmus in a thoroughbred mare

A 13-year-old, thoroughbred mare was presented with an 8-year history of multifocal, generalized, noninflammatory alopecia and a 3-month history of alopecia, erythema and scaling of the white star on the forehead and muzzle. Histopathological examination of biopsy samples from multiple sites on the body (mane, neck, shoulder, flank and gluteal region) showed a subtle lymphocytic inflammatory infiltrate affecting and surrounding the anagen hair bulbs, consistent with a diagnosis of alopecia areata. The biopsy sample from the star on the forehead showed atrophic hair follicles with perifollicular and mural mononuclear folliculitis affecting the isthmus. Immunohistochemical staining with a CD3 marker confirmed the T-lymphocytic origin of the inflammatory infiltrate in all the samples. The concurrent presence of lymphocytic infiltration at the bulbar and isthmic level of the hair follicles in the same horse is unusual. This finding may represent a variation of the histological appearance of alopecia areata.     

Immunohistochemical localization of fibroblast growth factor 18 in hair follicles of healthy beagle dogs

Increasing emphasis is being placed on the role of fibroblast growth factors (FGFs) in hair follicle cycling. In mice, expression of FGF18 mRNA peaks during the late telogen phase, leading to the hypothesis that FGF plays a role in anagen induction. There are no data on the presence of FGF18 in dogs. The main objective of this study was to identify and locate FGF18 in the canine hair follicle. The second objective was to assess potential differences in FGF18 concentration between biopsies taken in winter and summer, shoulder and flank regions, and between different sexes. Skin tissue from 10 healthy beagle dogs (three intact females, three spayed females and four intact males) was collected from the shoulder and flank. The biopsies were collected in February and August on day 0, after which the dogs were clipped and biopsies collected again from the shoulder and flank on days 1, 3, 7 and 17. Paraffin sections (4 μm thick) of the biopsies were stained with an anti-FGF18 antibody. The FGF18-positive cells were counted in the hair follicle epithelium from seven follicular units of each biopsy. Fibroblast growth factor 18 was detected as granular cytoplasmatic staining in follicles at the level of the inner root sheath, and rarely in the outer root sheath and dermal papilla. It was also detected in the apocrine glands, in arrector pili muscles and in vascular endothelial cells. There was no statistical difference in the number of FGF18-positive cells or follicles between sexes, different anatomical locations, seasons or the consecutive days of sampling.     

Alkaline phosphatase reaction in hair follicles of male beagle dogs during hair cycle stages.

The literature reviewed has revealed differences of opinion concerning the location of alkaline phosphates and its relationship to the hair cycle stages. This project was undertaken to determine alkaline phosphatase activity in the hair follicle stages: anagen, catagen, and telogen. Skin biopsy samples were collected over a period of 1 year from 9 purebred male Beagle dogs. At the beginning of the experiment 3 dogs were 2 weeks of age, 3 dogs were 12 months of age and 3 dogs were 21 months of age. The skin biopsies were taken monthly from alternate sides of each animal near the thoracolumbar region. Samples were fixed in 80% chilled alcohol and the alkaline phosphatase activity was determined by Gomori's calcium cobalt method. A total of 250 slides with seven sections per slide was examined. Each slide contained between 14–60 hair follicles. During anagen stage, the reaction of the dermal papilla for the presence of alkaline phosphatase was variable. A weak or negative reaction was observed in this study which was an unexpected finding. The reaction of the dermal papilla to alkaline phosphatase was positive in catagen stage. The cells of the dermal papillae in telogen stage were strongly alkaline phosphatase positive. The reaction was not confined to the blood vessels but occurred in all parts of the dermal papilla in both early and late stages.     

Skin morphology of thyroidectomized rats

We induced hypothyroidism in rats by conducting a thyroidectomy (TD) and investigated subsequent changes in the morphology of the skin, especially that of the epidermis and hair follicles. The 6 rats in the TD group seemed less active than the 3 rats in the control group and had cold, dry paws. All of the rats in the TD group exhibited retarded hair growth 12 weeks after surgery. Histologically, all of the rats in the TD group exhibited epidermal thinning from 12 weeks after surgery. Many hair follicles were in the telogen phase: the bulbs and papillae were involuted and had migrated towards the epidermis. Hair follicle atrophy involving thinning of the outer root sheath and the inner root sheath was often observed. The immunoreactivities of antithyroid hormone receptors alpha and beta in the outer root sheaths of 5 of the TD rats were weaker than those of control rats. Cell proliferation in hair follicles of TD rats was weaker than in follicles of control rats 4 weeks after surgery. It is suggested that decreased expression of TRs and decreased cell proliferation activity in the hair follicles of rats is associated with a lack of thyroid hormone and results in retardation of hair growth.     

Hoxc13在哺乳动物毛囊发育调控中的研究进展

同源盒C13(Hoxc13)基因与毛囊发育和毛发性状的形成密切相关.在哺乳动物毛囊的周期性发育过程中,Hoxc13通过调控角蛋白关联蛋白(KAP)基因等来控制毛囊在生长期、退行期和休止期之间转换,进而直接控制毛发性状的形成和改变,对皮毛动物产业发展具有重要的经济意义.本文围绕Hoxc13的结构特点、生物学功能以及作用机...     

A new type of lesion associated with severe fur damage in Canadian ranch foxes and an investigation of possible causes.

In the silver fox, as in its wild ancestor, the red fox (Vulpes vulpes L.), the annual growing phase (anagen) of guard hair follicles occupies at least four months. Severe damage to the hair coat near the end of this growing period was reported in 1985 on many ranches in New Brunswick and Nova Scotia. A histological analysis of serial sections of skin biopsies showed a marked increase in nuclear aberrations in the hair matrix of anagen guard hair follicles. These nuclear aberrations indicated that cells were undergoing apoptosis, a controlled form of cell death. Tissues from affected and unaffected foxes for histological and toxicological analysis, as well as other data, were obtained during visits to 26 ranches in 1986 and 34 ranches in 1987. Histological sections of the 1987 skin samples showed the mean percentage of nuclear aberrations in 43 unaffected foxes to be 0.08 +/- 0.01 (SEM), while that for 49 affected foxes was 0.51 +/- 0.23. The four foxes with the most severe coat damage also had the highest incidences of guard hair matrix cells with nuclear aberrations, ranging from 20 to 100 times greater than the mean for unaffected foxes. The mitotic index of the hair matrix, which normally remains fairly constant during the hair growth phase, was similar for unaffected and affected foxes (1.83 +/- 0.06 and 1.97 +/- 0.07 respectively). Although our analyses of field data have not established a specific environmental factor associated with increased nuclear aberrations, the possible involvement of toxic agents in follicle damage may warrant further investigation.     

毛囊的周期性变化和分子调控及其在绒山羊上的研究进展

毛囊是一个形态和结构较为复杂的皮肤附属器官,它控制着毛发的生长,具有自我更新和周期性生长的特点。毛囊的周期性变化依靠毛囊上皮细胞和真皮间充质细胞的相互作用,先是毛囊长出毛干为生长期,接下来是凋亡驱动的退行期,然后进入休止期。其变化过程是一系列信号分子相互作用形成的,包括启动信号、维持毛囊生长的信号及抑制毛囊生长的信号等。绒山羊初级毛囊和次级毛囊在出生后也表现周期性变化,次级毛囊由于光周期的影响而呈很强的季节性的周期变化,而初级毛囊则变化不明显。山羊绒是绒山羊次级毛囊的衍生物,次级毛囊的生长发育直接影响山羊绒的产量和品质。因此,研究皮肤毛囊周期性变化的规律及它们的分子调控机理不仅可揭示毛囊的发育规律而且对绒山羊的育种具有重要指导意义。     

Wnt10b参与外源褪黑激素促进绒山羊绒毛生长的研究

本实验旨在研究Wnt10b在内蒙古成年绒山羊皮肤中的表达变化规律和褪黑激素(MT)对其表达量的影响。每隔1个月按照2 mg/kg BW的剂量在受试内蒙古成年绒山羊耳后皮下埋植MT。连续采集12个月(从2009年8月到2010年7月)的肩胛部皮肤样品,应用实时荧光定量PCR技术检测Wnt10b的表达量。结果表明:Wnt10b在内蒙古成年绒山羊皮肤组织中毛囊生长中期和休止前期高表达;埋植MT提高了Wnt10b在内蒙古成年绒山羊皮肤组织中毛囊休止期和退行期的表达量。结果提示,Wnt10b参与内蒙古绒山羊毛囊生长的信号传递过程,并在退行期和休止期转变过程中发挥作用;Wnt10b参与了外源MT促绒毛生长的毛囊周期性变化过程。     

The effects of thyroid hormones on the skin of beagle dogs

The effects of hypothyroidism on canine skin were determined by comparing morphologic, morphometric, and hair cycle differences in skin biopsy samples from 3 groups of age- and gender-matched Beagle dogs: (1) euthyroid dogs; (2) dogs made hypothyroid by administration of 131I; and (3) dogs made hypothyroid and maintained in a euthyroid state by treatment with synthetic thyroxine. After 10 months of observation, there was slower regrowth of hair 2 months after clipping in the untreated-hypothyroid dogs. Untreated-hypothyroid dogs had a greater number of follicles in telogen and fewer hair shafts (ie, a greater number of hairless telogen follicles) than did the control group. The control dogs had a greater number of telogen follicles but the same number of hair shafts as the treated-hypothyroid group. Treated-hypothyroid dogs had the greatest number of follicles in the growing stage of the hair cycle (anagen). This study suggests that, at least in Beagles, induced hypothyroidism does not affect the pelage as dramatically as has been described in naturally occurring disease. This is because normal Beagles retain hair shafts in follicles for long periods, and the alopecia of hypothyroidism appears to evolve slowly because of the prolongation of this haired telogen stage. The evaluation of thyroxine-treated hypothyroid dogs demonstrates that thyroid hormone supplementation of Beagle dogs with induced hypothyroidism stimulates hair growth.     

辽宁绒山羊2品系皮肤毛囊周期性变化的比较研究

皮肤切片采用HE染色方法,对辽宁绒山羊常年长绒型品系和季节长绒型品系皮肤表皮厚、真皮厚、次级毛囊和初级毛囊深度、密度,次级毛囊和初级毛囊毛球宽度,S／P值等作了详细统计观察,从形态学方面研究了辽宁绒山羊皮肤毛囊在1年内的变化规律。结果表明：两品系辽宁绒山羊毛囊的兴盛期为4～10月,退行期为11～12月,休止期为1～3月,持续时间分别为7、2、3个月。兴盛期经历时间最长,退行期最短。但在毛囊的退行期,因为大多数毛囊的活性还很高,因此在退行期绒毛仍在生长,特别是在退行前期（10、11月份）还是绒毛的快速生长期。