Histological and molecular analysis of cerebellar regeneration in zebrafish (Danio rerio): Correlation of inflammatory response with activation of developmental pathways

Objective(s): This study aimed to characterize the temporal relationship among inflammatory responses, developmental gene reactivation, and structural restoration during cerebellar regeneration after mechanical injury in adult zebrafish.Materials and Methods: A focal cerebellar lesion was induced in ۳۰۰ adult zebrafish using a stereotaxic approach with a ۳۰-gauge needle. Histological analyses were performed at ۱, ۷, ۱۴, ۲۱, and ۲۸ days post-injury (dpi) using hematoxylin and eosin staining. Quantitative RT-PCR was used to assess the expression of inflammatory genes (tnf-α, il-۱β, and il-۱۰) and regeneration-associated genes (shha, pax۵, neurod, slc۱۷a۷a, ca۸, and aldoca) at defined post-injury intervals.Results: Histological examination revealed severe tissue disruption and inflammatory cell infiltration at ۱ dpi, followed by progressive reorganization of cerebellar architecture by ۲۸ dpi. Expression of tnf-α and il-۱β increased transiently during the acute phase, peaking at ۱۸-۲۴ hr post-injury before returning to basal levels. In contrast, il-۱۰ showed a delayed but robust induction, reaching maximal expression at ۱۸ hr and remaining elevated during the resolution phase. Developmental and neurogenic genes displayed distinct temporal profiles: shha and neurod peaked at ۷ dpi; pax۵ and slc۱۷a۷a reached maximal expression at ۱۴ dpi; whereas aldoca showed the strongest early induction. Quantitative analysis further confirmed a significant reduction in lesion size throughout the regeneration period.Conclusion: Zebrafish cerebellar regeneration involves a coordinated sequence of inflammatory, developmental, and neurogenic events. The temporal integration of immune modulation with reactivation of developmental pathways appears to be essential for successful restoration and provides insights into strategies for neural repair in vertebrates.

کلیدواژه ها:

Cerebellum ، Gene expression ، Inflammation ، Neural Stem Cell ، Neurogenesis ، Regeneration ، Zebrafish