Effects of Substance P on the Hair Growth in Human Hair Follicle Organ Culture

Sohn, In Bum; Lee, Won Soo

Abstract

BACKGROUND: In vitro, some neuropeptides, including substance P(SP), act as a growth factor. The cyclic growth of the richly innervated hair follicle offers a model for probing such functions in a complex, developmentally regulated tissue interaction system under the physiologic condition. Dissecting the role of neuropeptides in this system may also reveal as yet obscure neural mechanisms of hair growth control.
OBJECTIVE
The purpose of this study was to investigate the effect of SP on human hair growth using a recently described model in which isolated hair follicles are grown in vitro.
METHODS
After the healthy human hair follicles without any visible damage were collected, they were cultured in DMEM with several combination of supplements including insulin, hydrocortisone, sodium selenite, human transferrin, fetal bovine serum at 37 degrees C in an atmosphere of 5% CO2 /95% air incubator, and SP was added to the media. The culture media were supplemented with final concentration of 10(-6),10(-7),10(-8) M SP dissolved in DMEM. The results were evaluated by measuring linear hair fiber growth and hair follicle morphology on light microscopy and electron microscopy and by measuring radioisotope uptake of [methyl-3H] thymidine and [U-14C] leucine of hair follicle.
RESULTS
The following results were obtained from this study. 1. SP did not have an statistically significant effect on the rate of linear hair growth in cultured hair follicles. However, it prolonged the anagen stage of hair cycle. 2. We could not find morphological differences of hair follicles cultured in SP groups compared with those cultured in control group. 3. DNA and protein synthesis in hair follicles increased steadily for 5 days of culture.
CONCLUSION
From the results, we can conclude that SP has growth-stimulatory effect and especially prolongs the duration of anagen phase without affecting the rate of linear hair growth.