Figure 1.

Tyrosine hydroxylase (TH) expression in the substantia nigra of rats (immunohistochemical staining, light microscope, scale bars: 500 μm).

A large number of TH-positive cells with deeply colored cell bodies and abundant processes were observed in the substantia nigra of normal rats (A).

Compared with normal rats (A), the numbers of TH-positive cells and processes in model rats at 4 days (B) were clearly decreased, and lighter colored cell bodies were seen.

The loss of TH-positive cells was aggravated in model rats at 14 days (C) and 28 days (D).

Gastrodin at 14 days increased the numbers of TH-positive cells and processes (E) compared with the model group at 14 days (C).

The numbers of TH-positive cells and processes of Madopar-treated rats also tended towards a decrease at 14 days (F).