The effects of exogenous melatonin and prolactin on wool follicle development in ovine foetal skin grafts

1993 ◽  
Vol 44 (5) ◽  
pp. 993 ◽  
Author(s):  
CE McCloghry ◽  
DE Hollis ◽  
A Foldes ◽  
AJ Rintoul ◽  
P Baker ◽  
...  
Keyword(s):  
Nude Mice ◽  
Follicle Development ◽  
Skin Grafts ◽  
Epidermal Thickness ◽  
Exogenous Melatonin ◽  
Merino Sheep ◽  
Secondary Follicle ◽  
Wool Follicle

The fleece of the Merino sheep is composed predominantly of wool fibres grown from secondary wool follicles. This study investigates the effects of melatonin and prolactin on the development of secondarv follicles in grafted ovine foetal skin. Skin from day 85 ovine foetuses was grafted onto nude mice, developed for 40 days and then excised. Mice received either 30 8g prolactin ip mouse-1 day-1 (P), one melatonin implant (Regulin�) sc mouse -1 (M), commencing at grafting or no further treatment (C). Wool follicle density and development were assessed in grafted skin and compared with day 125 control foetal skin. Cuticle structure of graft fibres was also examined and compared with those of day 125 foetuses. Total follicle density and the rate of follicle initiation were reduced in the grafts compared with control foetal skin. Total follicle density did not vary significantly between treatments, but the number of derived secondary follicles was greater in grafts from mice receiving prolactin (group P). Follicles in grafted skin were larger, produced medullated fibres, and were not grouped, in comparison with follicles in the control foetal skin. Epidermal thickness was greater in grafts than in control foetal skin. The cuticle structure of graft fibres from all groups was similar to the control wool fibres. These findings indicate that prolactin, but not melatonin, may be involved in the regulation of derived secondary follicle development.

Perinatal wool follicle attrition coincides with elevated perinatal circulating cortisol concentration in Merino sheep

2007 ◽  
Vol 58 (7) ◽  
pp. 748 ◽  
Author(s):  
A. C. Toland Thompson ◽  
M. L. Hebart ◽  
N. M. Penno ◽  
P. I. Hynd
Keyword(s):  
Surface Area ◽  
Plasma Cortisol ◽  
Post Partum ◽  
Skin Surface ◽  
Cortisol Concentration ◽  
Primary Follicle ◽  
Merino Sheep ◽  
Secondary Follicle ◽  
Plasma Cortisol Concentration ◽  
Wool Follicle

The development of the follicle population in Merino sheep skin was studied from 30 days pre-partum to 112 days post-partum in single- and twin-born Merino lambs. The total number of primary follicles estimated from primary follicle density and skin surface area did not change over this period, while secondary follicle number increased to Day 28 post-partum in singles and Day 56 post-partum in twins. Twins had 14% fewer total follicles than singletons (P < 0.001), largely reflecting a bodyweight (hence estimated skin surface area) difference of 10%, with little difference in total follicle density (P > 0.05). Immediately post-partum there was a 36% decrease (P < 0.0001) in the secondary to primary follicle ratio (S/P) of the twin lambs, while a small non-significant decrease (7%; P > 0.05) occurred in the single lambs. This attrition coincided with a surge in plasma cortisol concentration that commenced ~12 days before birth and persisted for 6–12 days post-partum. The surge in plasma cortisol concentration occurred in both single and twin lambs, commencing on Day 138 of gestation; however, the peak cortisol concentration and the period over which cortisol remained elevated was greater in twin lambs than in singletons (P < 0.001). This study confirms a previous finding of a perinatal reduction in S/P ratio in Merino sheep. The reduction was greater in twin lambs than in singletons but the follicles of twins recovered rapidly so that there was little difference in final S/P ratio between birth types after Day 30 post-partum. The postnatal follicle reduction followed the perinatal surge in plasma cortisol concentration and appeared to reflect the magnitude of the cortisol surge in that twins, which displayed a higher peak cortisol concentration, had a greater reduction in active follicles than singletons.

scholarly journals MAINTENANCE OF SKIN XENOGRAFTS OF WIDELY DIVERGENT PHYLOGENETIC ORIGIN ON CONGENITALLY ATHYMIC (NUDE) MICE

1973 ◽  
Vol 138 (2) ◽  
pp. 488-494 ◽  
Author(s):  
Dean D. Manning ◽  
Norman D. Reed ◽  
Charles F. Shaffer
Keyword(s):  
Nude Mice ◽  
Tree Frog ◽  
Skin Grafts ◽  
Intact Skin ◽  
Athymic Nude Mice ◽  
Phylogenetic Origin ◽  
Definitive Role

Congenitally athymic (nude) mice accepted for their lifetime intact skin grafts from distantly related mammals (cat, human) and birds (chicken). They also failed to immunologically reject skin grafts from reptiles (lizards) and amphibians (tree frog), although the skin in these grafts underwent varying degrees of disorganization. A definitive role for the thymic defect in this failure to reject xenografts was established by showing that thymus implantation into nude mice enabled them to reject such foreign skin.

Full-Thickness Skin Grafts from Flaky Skin Mice to Nude Mice: Maintenance of the Psoriasiform Phenotype

1994 ◽  
Vol 102 (5) ◽  
pp. 781-788 ◽  
Author(s):  
John P Sundberg ◽  
Robert W Dunstan ◽  
Wesley G Beamer ◽  
Dennis R Roop
Keyword(s):  
Nude Mice ◽  
Skin Grafts ◽  
Full Thickness ◽  
Full Thickness Skin ◽  
Thickness Skin

scholarly journals Factors Mediating the Interactions Between Epidermal and Dermal Cells in Skin Grafts that Might Be Important for Hair Follicle Development

1995 ◽  
Vol 104 (5) ◽  
pp. 21-22 ◽  
Author(s):  
Tonja Kartasova ◽  
Aline B. Scandurro ◽  
Mitchell F. Denning ◽  
Stuart H. Yuspa ◽  
Ulrike Lichti ◽  
...  
Keyword(s):  
Hair Follicle ◽  
Follicle Development ◽  
Skin Grafts ◽  
Hair Follicle Development ◽  
Dermal Cells

Is epidermal cell proliferation in psoriatic skin grafts on nude mice driven by T-cell derived cytokines?

1992 ◽  
Vol 126 (2) ◽  
pp. 105-110 ◽  
Author(s):  
B.S. BAKER ◽  
L. BRENT ◽  
H. VALDIMARSSON ◽  
A.V. POWLES ◽  
L. AL-IMARA ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
T Cell ◽  
Epidermal Cell ◽  
Nude Mice ◽  
Psoriatic Skin ◽  
Skin Grafts ◽  
Epidermal Cell Proliferation

Wool follicle development in the New Zealand Romney and N type sheep. II. Follicle population density during foetal development

1958 ◽  
Vol 9 (1) ◽  
pp. 138 ◽  
Author(s):  
SK Stephenson
Keyword(s):  
New Zealand ◽  
Population Density ◽  
Subsequent Development ◽  
The Body ◽  
Limiting Factor ◽  
Follicle Development ◽  
Primary Follicle ◽  
Foetal Development ◽  
Secondary Follicle ◽  
The Face

Quantitative aspects of follicle initiation and development have been studied in a series of N-type and New Zealand Romney foetuses. Density of the follicle population and ratios of secondary to primary follicles were examined on 13 positions of the body which covered the main wool-bearing areas, the face and head, and the limbs. Primary follicle development is initiated first on the head and limbs and throughout subsequent development these regions are most advanced. Primary follicle density reaches a maximum between 75 and 90 days of foetal age, after which it decreases as a result of skin growth. Secondary follicle initiation is more rapid on the wool-bearing areas of the body, and higher ratios of secondary to primary follicles are recorded from these regions. No real differences have been found between N-type and New Zealand Romney foetuses in population density of the different follicle types at any age or in the number of secondary follicles developed per primary follicle. The growth of larger primary fibres and follicles in N-type foetuses is not accompanied by, and does not result from, a lower density of primary follicles. There does not appear to be any marked relation between the decreasing density of primary follicles after 90 days of foetal age and the initiation of secondary follicle anlagen. This fact, and the absence of any differences in the number of secondary anlagen formed per primary follicle in N-types, suggest that crowding in N-types is not a limiting factor in the formation of secondary follicle anlagen.

scholarly journals Identification and characterization of circRNAs in the skin during wool follicle development in Aohan fine wool sheep

BMC Genomics ◽  
2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Ranran Zhao ◽  
Nan Liu ◽  
Fuhui Han ◽  
Hegang Li ◽  
Jifeng Liu ◽  
...  
Keyword(s):  
Follicle Development ◽  
Wool Follicle ◽  
Identification And Characterization
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