Effect of Interleukin-1Beta (IL-1<i>β</i>) on the Cortical Neurons Survival and Neurites Outgrowth

Insults to the brain are known to cause a myriad of downstream effects, including the release of cytokines by astrocytes and resultant reactive gliosis. The author has examined effect of cytokine IL-1β on the survival of cortical neurons using mouse astrocyte-neuron co-culture. Five groups were used. These were neurons alone (Group 1), neurons with added IL-1β (Group 2), neurons co-cultured with astrocytes (Group 3), neurons co-cultured with astrocytes that was pre-treated with IL-1β before co-culture (Group 4) and neurons co-cultured with astrocytes and IL-1β added (post-treated) (Group 5). In Group 1 only a few neurons grew and survived only for 5-6 days. In Group 2, it was observed that more neurons survived up to 11 days. Moreover, in Group 3, more neurons grew and survived up to 16-18 days. They had large cell bodies and many long neurites that formed anastomosing networks. In Group 4, few neurons survived up to 13 days, whereas in Group 5, the growth of neurons were affected but to a much lesser extent than Group 4 and survived up to 15 days. In addition, it was found that IL-1β stimulated the expression of glial fibrillary acidic protein (GFAP) by astrocytes. This study indicates that IL-1β affects the survival of cortical neurons and modulates the astrocytic support to neuronal survival and neurites outgrowth by acting directly on the astrocytes.