[Effects of different parts of the follicle-unit grafts subjected to controlled injury].

Objective: To study the shaft elongation and morphological changes of follicle-unit (FUs) grafts subjected to controlled injury in different parts.
Methods: Human FUs were isolated by microdissection under a dissecting microscope. The single hair of anagen FUs were randomly divided into A, B and C groups, and A and B groups were subjected to controlled injury with microsurgery imposed to the dermal papilla and the bulge of FUs, respectively, with C as the control group without any treatment. HE staining was used to detect the histological changes of the cells, and organ culture for 10 days was conducted to observe the morphological changes and elongation of FUs.
Results: There were no histological or morphological changes in A, B and C groups. The average elongation of hair shaft was 1.293-/+0.245, 2.116-/+0.423 and 2.235-/+0.379 mm, respectively. There were significant differences between groups A and B (P<0.05) and between groups A and C (P<0.05). No significant difference was found between groups B and C (P>0.05).
Conclusion: Damage of the dermal papilla should be avoided in hair transplantation surgery.