A Single Cisterna Magna Injection of AAV Leads to Binaural Transduction in Mice

Viral-mediated gene augmentation, silencing, or editing offers tremendous promise for the treatment of inherited and acquired deafness. Inner-ear gene therapies often require a safe, clinically useable and effective route of administration to target both ears, while avoiding damage to the delicate structures of the inner ear. Here, we examined the possibility of using a cisterna magna injection as a new cochlear local route for initiating binaural transduction by different serotypes of the adeno-associated virus (AAV2/8, AAV2/9, AAV2/Anc80L65). The results were compared with those following canalostomy injection, one of the existing standard inner ear local delivery routes. Our results demonstrated that a single injection of AAVs enables high-efficiency binaural transduction of almost all inner hair cells with a basal-apical pattern and of large numbers of spiral ganglion neurons of the basal portion of the cochlea, without affecting auditory function and cochlear structures. Taken together, these results reveal the potential for using a cisterna magna injection as a local route for binaural gene therapy applications, but extensive testing will be required before translation beyond mouse models.

A Non-invasive Method of Cerebrospinal fluid collection from rats for assessing the Cerebrospinal fluid drug content

The drug discovery and pharmacokinetic studies of drugs of the central nervous system depend on the successful collection of cerebrospinal fluid from lab animal models. Many a time, the treatment regime and management of diseases depends on the penetration and distribution of medicaments across the blood-brain barrier and for which a non-contaminated cerebrospinal fluid sample is essential. The present study was to simplify the cerebrospinal fluid collection from cisterna magna of rat, maximizing the quantity and minimizing the contamination. The rat is anaesthetized with Xylazine Ketamine combination intravenously and was kept on an inverted polypropylene tray with its head down at 45° angle. A depressible surface which look like a rhomb between occipital protuberances and the spine of the atlas becomes noticeable. A butterfly needle attached to a syringe was introduced into the cisterna magna, and cerebrospinal fluid is aspirated. The method is non-invasive and doesn’t require any sophisticated equipment and lessens the chance of contamination of the sample with blood. The technique is also less time consuming and easy to perform.