Sympathetic Reinnervation of Intact and Upper Follicle Xenografts into BALB/c-nu/nu Mice

The study "Sympathetic Reinnervation of Intact and Upper Follicle Xenografts into BALB/c-nu/nu Mice" investigated the role of sympathetic nerves in hair growth after transplantation. Rat vibrissa follicles were transplanted into BALB/c-nu/nu mice, with two types of follicles used: intact follicles and upper follicles. At 37 days post-implantation, both types of follicles had entered the anagen phase (growth phase) and showed significant growth of long hair shafts. The study also found that tyrosine-hydroxylase-positive nerves, a marker for sympathetic nerves, were innervating the follicles (1.45-fold increase) and norepinephrine concentrations, a neurotransmitter involved in hair growth, were significantly increased (2.03-fold) compared to 5 days post-implantation. However, these levels did not return to normal. The study concluded that both intact and upper follicle xenografts survived and showed partial restoration of sympathetic reinnervations, which are crucial for hair growth. The number of mice used for each condition ranged from 3 to 10.