Is mad cow disease related to gliosis?

No: Mad cow disease is believed to be a disease caused by the build up (and transmission) of a certain protein in the nerves of our brain. The resultant damage can cause gliosis, but gliosis can also occur in a variety of conditions other than mad cow disease. Gliosis is a term to explain "scarring" in the brain that could be caused by trauma, infections, tumors, radiation therapy, etc.