An immunohistochemical study of enteric nervous system in the chick model

The chick model is a useful research tool to investigate the development of the enteric nervous system (ENS). Recognition of appropriate markers for detection of chick enteric ganglia will allow better utilization of this model to study abnormalities of the ENS. This study aimed to validate a set of antibodies for avian ENS studies on wax sections. The specimens were taken from jejunum and colorectum of early post-hatching chicks, fixed in 4% buffered formaldehyde and stained using haematoxylin and eosin (H &E). Glial fibrillary acidic protein (GFAP), neuron specific enolase (NSE), synaptophysin and S-100 immunohistochemical biomarkers were employed on paraffin-embedded blocks to identify enteric ganglia. The immuno-reactivity scoring was recorded using a semi-quantitative fourtiered system (0, 1+, 2+, and 3+). In jejunum specimens, the immune-reactivity of GFAP was significantly higher than both synaptophysin (p=0.001) and S-100 (p=0.001). There was also a significant difference (p=0.03) between the immune-reactivity induced by NSE and S-100 in the jejunum samples. Significant differences were observed between GFAP immuno-reactivity and both synaptophysin and S-100 (p=0.013; and p =0.005, respectively) in the samples collected from colorectum. The level of immuno-reactivity between NSE and both synaptophysin and S-100 biomarkers in the colorectal specimens were also different significantly (p=0.02 and 0.007,respectively). The results of the present work showed that GFAP and NSE biomarkers can be used with high immuno-reactivities to examine the chick enteric ganglia as an appropriate animal model in ENS developmental disorders.