Histopathological evaluation of the effect of low level laser therapy on prevention of hair follicle necrosis in experimental cryosurgery indued wounds in rats

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.

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. 

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 21st and 28th 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).

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.