Background: Recently, the number of studies investigating the molecular genetic mechanisms underlying nervous system function in both normal and pathological states has increased significantly. Despite the identification of numerous proteins involved in neural metabolic processes, interest in key regulatory proteins continues to grow. In particular, annexin A2 (ANXA2), previously known for its role in cancer, is gaining attention for its potential role in the development of neurodegenerative diseases. 
 
Methods: This study was conducted on Danio rerio of the AB line. Knockdown of the Anxa2a was achieved by microinjection of translation-blocking morpholino oligonucleotides (MOs). The control group was injected with a standard control MO. Phenotypic analysis was performed at 2 days post-fertilization (dpf). Knockdown efficiency was assessed by Western blotting. Relative mRNA levels of target genes (ahnak, egf, egfra, ptena, ptenb, gfap, psen1, psen2) were determined by real-time PCR. 
 
Result: Phenotypic analysis of the Mo-Anxa2a group across several experimental replicates revealed hydrocephalus (enlargement of the hindbrain ventricle, HBV), as well as eye and olfactory pit deformities. These effects were absent in the control group. Analysis of hydrocephalus severity in morphants identified two subgroups: those with severe and those with mild enlargement of the hindbrain ventricle. Western blotting confirmed a 2-fold reduction in Anxa2a protein levels without a change in its mRNA levels, confirming successful knockdown at the translational level. Furthermore, all groups with Anxa2a knockdown exhibited a statistically significant downregulation of ptena, ptenb, gfap, psen1 and psen2. Notably, in D. rerio with severe hydrocephalus, decreased expression of egf and egfra was also observed, suggesting the involvement of these genes in the pathogenesis of severe hydrocephalus.

Knockdown of Anxa2a Expression Causes Hydrocephalus in Danio rerio

<div>Background: A Jersey Cross bred heifer (3 years) was presented to Large Animal Obstetrical Unit of Veterinary College and Research Institute, Orathanadu with a bilaterally distended abdomen suffering from dystocia. The present work was aimed to study the diagnosis and effect of therapeutic intervention for dropsy of fetal membranes and fetus.&nbsp; 
 
Methods: The animal was observed for general examination and subjected to clinical investigation. Vaginal examination revealed patent vaginal passage with dilated cervix. Fetal head could be palpable on further deep vaginal examination. In addition, a uterine tear was also palpable on the lateral side of the birth canal at 5&rsquo; O&rdquo; clock position. 
 
Result: Based on the clinical observations, the case was diagnosed as dystocia due to dropsy of fetal membranes with uterine tear. The animal was restrained and stabilized with 3 L of Inj. Normal saline intravenously. Under paravertebral nerve block cesarean section was performed and a dead male fetus with hydrocephalus was removed. Approximately about 280 L of mixed fetal fluids were drained. Postoperatively the animal was treated for seven days and the animal had uneventful recovery after 2 weeks of suture removal.</div>

Knockdown of Anxa2a Expression Causes Hydrocephalus in Danio rerio

Dropsy of Fetal Membranes Combined with Hydrocephalus in a Jersey Crossbred Heifer