Cisterna magna double-injection model of hemorrhagic stroke in experimental rats for the study of communicating hydrocephalus

Abstract

Objectives. The cisterna magna double-injection model of hemorrhagic stroke (CMDIM) was tested in this research to see its validity in provoking communicative hydrocephalus. Background. Subarachnoid hemorrhage (SAH) is a devastating disease resulting in high mortality and is a common cause of chronic post-hemorrhagic hydrocephalus (PHH), which affects up to 20% of the survivors. The occurrence of hydro- cephalus after SAH is a crucial factor in predicting a poor prognosis, including damage to the brain parenchyma, a prominent cause of disability that, if sufficiently severe, may also lead to patient mortality. In the case of PHH, the mechanisms leading to pathogenesis are poorly understood. Small animal models in basic and preclinical sciences constitute an integral part of testing new hypotheses before translation to clinical practice. Methods. Experimental animals were divided into two groups. The first group (control group – CG) was without surgery. In the second group, a 0.15 ml blood injection into cistern magna was followed by a 0.15 ml blood injection 48 hours later. The surgery was performed in sterile condi- tions under general anesthesia; experimental animals in the surgical group were positioned supine, and blood was taken from the lower third on the ventral aspect of the tail. After this, the rat was turned prone, and the head was fixed in a stereotactic frame. Under magnification of surgical loups, an incision was made in the suboccipal region followed by dissection of neck region muscles. Gentle flexion of the rat head allowed by not rigid head fixation gave the possibility to widen the space between the occipital bone and C1 lamina for better cisterna magna visualization. After meticulous hemostasis, the incision was closed using a stapling device. The second surgery was performed with the same steps, except for more proximal puncturing (above the lower third on the ventral aspect of the tail) of the tail artery. We defined hydrocephalus as ventricular vol- ume on histological evaluation, which was > +3 SDs above the mean in control animals. Results. Thirty-seven operations were done on 20 rats with 20% posthemorrhagic postoperative mortality. Hydrocephalus in the surgical group occurred in 45% of rats, according to the histological investigations. Conclusion. Based on the findings, CMDIM is effective in generating posthemorrhagic hydrocephalus with acceptable mortality.