Fig. 4.

Cerebellar Purkinje cell development and Sonic hedgehog (Shh) expression in preterm (PT) and term (T) rabbit pups. A The development of Purkinje cells was evaluated by their morphology as determined by calbindin staining using a bright-field microscope as described in Material and Methods. Cell maturity over time, i.e. dendritic length and arborization, and their formation into the Purkinje cell layer were compared between the 2 groups at each postnatal time point. Representative immunosections of Purkinje cell morphology in PT and T pups are shown at each postnatal time point and also the progressive maturation from a fuciform to a stellate state. Calbindin staining (brown) was decreased in the PT group at P0 and P2 (vs. in the T group), with reduced arborization and dendritic spines. B Immunostaining for Shh was performed in sections from PT and T pups at each postnatal time point as described in Material and Methods. The pattern and intensity of staining for Shh were similar in the PT and T groups. Shh staining was scattered and present within the external granular layer, like in the internal granular layer, at early postnatal time points, and was restricted to the Purkinje cell somata (brown) at later time points. Scale bar, 50 µm. C Quantitative analysis of calbindin staining showed a decrease in the area (%) of calbindin-labeled Purkinje cells in the PT pups versus in the T pups at P0 (p = 0.003), P2 (p = 0.004), and P5 (p = 0.04).