Optogenetics is a modern technique in neuroscience to control excitable cells with light and has recently been used on electrically non-excitable cells like astrocytes. This procedure involves introduction of a viral vector with a light sensitive protein which facilitates cationic influx into the astrocyte upon activation. The viral construct of interest is AAV-GFAP-hChR2 (H134R)-mCherry. However, to perform transduction in astrocytes, an evaluation of the serotypes of the Optogenetic vector is necessary. This research is focused on finding the ideal serotype of the optogenetics virus in an in vivo rat model. The plausible serotypes for the study were narrowed down to serotypes 1, 5 and 8, based on previous studies in the spinal cord and the rat brain targeting neurons. This evaluation would help us understand the expression of the gene conferring light sensitivity to the astrocytes, and thereby allowing us to control them using light. The validation of viral expression has been performed by post mortem histological analysis. From the preliminary data, serotype 8 shows promising transduction patterns in astrocytes in the cerebral cortex in terms of the highest spread as well as the largest area of expression in the brain tissue. This approach would help gain control of astrocytes, which can be used to study various pathological conditions in the mammalian brain. The optogenetics methodology will be employed to delve into the response of astrocytes to light stimulation allowing the study of neuroinflammatory and functional changes associated with glioreactivity.
