HAMr: A Mechanical Impactor for Repeated Dynamic Loading of In vitro Neuronal Networks

A new tool for exploring the effects of repeated low-amplitude mechanical impacts onto in vitro neuronal networks is presented. The experimental setup, HAMr, is specifically designed to allow variability in impact conditions while ensuring a highly repeatable result. HAMr’s functionality to induce inflammation related to mild traumatic brain injuries has been validated by assessing its capability to induce elevated expression of the inflammatory protein IL-1 β in in vitro neuronal cell cultures. The two main results obtained for the inflammatory response in dissociated cortical networks, presented for a range of impact force amplitude and total number of impacts, can be summarized as follows. First, the results demonstrate a strong correlation between ensuing inflammation level and numbers of impact. Second, the results indicate a possible existence of a safe threshold of number of impacts that does not initiate an inflammatory response.