Development of a nude mouse model to study human sebaceous gland physiology and pathophysiology.

Abstract

Study of human sebaceous gland physiology and pathophysiology is limited by lack of an adequate animal model. This study was designed to develop an animal model using human face skin grafted onto the nude mouse to study human sebaceous glands. Full-thickness human face skin was grafted onto 60 adult male nude mice. 4 wk after grafting, androgens, which are known to stimulate sebaceous glands, were administered to test the system. Androgens were administered to 21 animals by implanted catheters that were filled with testosterone (T) or dihydrotestosterone (DHT). Empty catheters were implanted in 15 control animals. Graft biopsies and blood for androgen levels were obtained at time 1 (pre-catheter) and time 2 (26 d after catheter implantation). Three assessments were made on each biopsy: sebaceous gland volume, using an image analyzing computer; sebaceous cell size; and sebaceous gland labeling index. 29 mice completed the study through time 2. In the androgen-treated group, T levels (nanogram per milliliter) five times increased to 4.92 +/- 0.35, and DHT levels (nanogram per milliliter) increased 50 times to 16.70. In the androgen-treated group, sebaceous gland volume (micron 3 X 10(-3) increased from 896 +/- 194 to 3,233 +/- 754 (P less than 0.001), sebaceous cell area (micron 2) increased from 167 +/- 12 to 243 +/- 19 (P less than 0.001), and labeling index (percentage) increased from 2.7 +/- 0.7 to 6.4 +/- 0.9 (P less than 0.01). In the control group, sebaceous gland volume fell from 1,070 +/- 393 to 417 +/- 99 (NS), sebaceous cell size remained the same, and the labeling index fell from 5.1 +/- 1.9 to 3.2 +/- 1.1. After androgen administration, Halowax N-34, a known comedogen, or its vehicle, was applied to 15 grafts for 2-6 wk. Twice as many microcomedones were seen in the Halowax-treated grafts, compared with vehicle-treated grafts at the end of this time period. No visible comedones were produced. This study demonstrated that: (a) human sebaceous glands can be successfully transplanted and studied on the nude mouse; (b) after androgen stimulation, sebaceous gland volume, cell size, and labeling index increase; (c) microcomedones can be produced in the human skin grafts by the application of a comedogenic substance. Thus, this model demonstrates significant potential for the future study of human sebaceous gland physiology and pathology.