Related Experiment Video
Updated: Aug 6, 2026
Flat Mount Imaging of Mouse Skin and Its Application to the Analysis of Hair Follicle Patterning and Sensory Axon Morphology
Published on: June 25, 2014
Age-related changes in the dorsal skin histology in Mini and Wistar rats
1Department of Veterinary Pathology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Japan.
Abstract:
Mini rats (Jcl: WistarTGN(ARGHGEN)1Nts (MRs) are Wistar rat (WR)-derived transgenic rats in which the expression of growth hormone (GH) gene is suppressed by the presence of antisense transgene. The plasma GH level of MRs is reduced to 40 to 60% of that of WRs. In this study, to evaluate the influence of GH deficiency on the skin nature, age-related changes in the dorsal skin histology were compared between male MRs and WRs. Although there were no essential differences in the skin structures between the two strains, MRs had thinner skin with less collagens, more abundant subcutaneous adipose tissues and small-sized sebaceous glands compared with WRs. On the other hand, the hair cycle evaluated by the morphology and the depth of hair follicles was greatly different between them. Namely, two cycles of 4 weeks each were observed in both strains during the first 8 weeks after birth, but the cycle entered a long-lasting quiescence (telogen phase) in MRs while the 3rd cycle started in WRs afterwards. The lower level of serum insulin-like growth factor (IGF)-1 in MRs may be related to such a difference in hair cycle pattern, although the levels of IGF-1 and IGF-1 receptor mRNAs in the dorsal skin tissues were similar between MRs and WRs. MRs are considered to be a useful animal model for dermatopathy in patients suffering from GH deficiency and for grasping a clue to elucidate the exact effects of GH on the skin nature, especially on hair follicle development.
Insights
Mini rats with suppressed growth hormone (GH) exhibit thinner skin and altered hair cycles compared to Wistar rats. This suggests GH deficiency impacts skin structure and hair follicle development, offering insights into dermatological conditions.
Area of Science:
- Dermatology
- Endocrinology
- Animal Models
Background:
- Transgenic mini rats (MRs) exhibit suppressed growth hormone (GH) expression, reducing plasma GH levels to 40-60% of Wistar rats (WRs).
- Understanding the influence of GH deficiency on skin characteristics and hair follicle development is crucial for dermatological research.
Purpose of the Study:
- To investigate the age-related changes in dorsal skin histology and hair cycle patterns in GH-deficient mini rats compared to normal Wistar rats.
- To evaluate the potential of mini rats as an animal model for studying GH deficiency-related dermatopathies.
Main Methods:
- Comparative histological analysis of dorsal skin from male mini rats and Wistar rats.
- Evaluation of skin structure, collagen content, adipose tissue, sebaceous glands, and hair follicle morphology.
- Assessment of hair cycle phases and duration.
Main Results:
- Mini rats displayed thinner skin with reduced collagen, increased subcutaneous adipose tissue, and smaller sebaceous glands compared to Wistar rats.
- Significant differences in hair cycle patterns were observed, with mini rats entering a prolonged telogen (quiescence) phase, unlike Wistar rats.
- Lower serum insulin-like growth factor (IGF)-1 levels in mini rats may correlate with altered hair cycle dynamics, despite similar IGF-1 mRNA levels in skin tissue.
Conclusions:
- GH deficiency in mini rats leads to distinct skin phenotypes, including thinner skin and disrupted hair follicle cycling.
- Mini rats serve as a valuable model for investigating the dermatological effects of GH deficiency and understanding GH's role in skin and hair biology.
- Further research using this model can elucidate the mechanisms underlying GH's influence on skin aging and hair follicle development.
