Chronic systemic administration of tumor necrosis factor alpha and HIV gp120: Effects on adult rodent brain and blood-brain barrier

Since tumor necrosis factor alpha (TNF-α) and HIV gp120 glycoprotein are both neurotoxic, the possibility that systemic sources of these two agents mediate AIDS-associated blood-brain barrier (BBB) breakdown and brain damage was tested in two murine models: (1) intramuscular implantation of a TNF-α-transfected tumor in nu/nu mice and (2) daily subcutaneous injections of HIV gp120 in BALB/c mice. The BBB remained intact; brain damage was not found, and apoptotic cell numbers did not increase. These results show that normal adult brain and BBB is unaffected by exposure to TNF-α or HIV gp120 and suggest that severity of brain disease is not directly affected by systemic levels of these compounds.