Journal of

Emergence and spread of various diseases in the past century have been associated with many problems for the health care providers. Now a days, with advancement of technology, new methods such as cell therapy, are available, efficient and successful in some clinical areas. To use any cell, it is necessary to identify its source, so herein, we reviewed the literature of a new source of adult stem cells in the bulge of hair follicle.

Hair is composed of two parts: root and shaft. Proximal two-thirds of the hair root, called hair follicle that is surrounded by two dermal and epidermal sheaths. Epidermal sheath included inner and outer root sheath. Outer root sheath at the junction of the errector pilli muscle and sebaceous glands make the bulge that includes stem cells.

In this review we described anatomy of the hair follicle, hair growth cycle, hair follicle bulge, embryonic source of hair follicle, isolation of bulge stem cells using cell surface markers, gene expression and differentiation in bulge stem cells directing differentiation of bulge stem cells in normal skin repair, and practical advantages of bulge stem cells over other stem cells.

Background and Aim: Alopecia by reduction of hair follicles at the wound healing site is a complication of cryosurgery that creates an unpleasant appearance in the scar of healed tissue. The aim of this study was to evaluate the effect of low level laser on preventing necrosis of hair follicles and increasing hair follicles in cryosurgery induced wounds.

Methods: Fifty male Wistar rats were randomly divided into 2 main experimental and control groups (with and without low power laser) and 5 subgroups. Histopathological examination of the amount of hair follicle count and angiogenesis at intervals of 3, 7, 14, 21 and 28 days was performed in the laboratory. SPSS software was used for statistical analysis. 

Results: There was no significant difference in the  angiogenesis had significantly index between the main groups on days 14 and 21 (P>0.05), but on days 3, 7 and 28, the experimental group had significantly higher angiogenesis than the control group. Throughout the days, both groups showed a significant increase in angiogenesis (P<0.05), except for the third and seventh days in the control group, and in both groups between the 21^st and 28^th days (P>0.05). In the comparison of hair follicle index, there was an increase on all days, which was significantly higher in the experimental group than the control group (P<0.05). However, no statistical difference was observed between the third and seventh days (P>0.05).

Conclusion: The use of low-power lasers on cryosurgery induced wounds with scars and alopecia can prevent hair follicles necrosis and subsequent increase in their numbers in rats.