LE3 .A278 2013

2013

Wilson, Brian

Acadia University

Bachelor of Science

Honours

Biology

Biology

Relaxins are peptides belonging to the insulin/relaxin superfamily of peptides. Aside from well-established roles in pregnancy, evidence suggests that relaxins may have other roles in the body, including the protection of tissues during periods of ischemia. During a heart attack, relaxin has been shown to have vasodilatory and anti-inflammatory actions which protect tissue from ischemic conditions. Recent evidence suggests that relaxin has neuroprotective actions in response to ischemia as it does in the myocardium. In this study, we investigated the neuroprotective potential of two relaxin peptides, H2 relaxin (the main circulating form) and H3 relaxin (found exclusively in the brain), by testing whether either of them inhibit apoptosis (programmed cell death) resulting from oxygen and glucose deprivation (OGD) in organotypic rat brain slice cultures. Apoptosis was assessed indirectly using an ELISA to measure histone content in total protein isolated from brain slices. In addition, an immunofluorescence assay was used to identify caspase-3-positive cells in slices. Cultured brain slices from day-10 neonatal rats were randomly divided among four treatment groups each lasting 1 hour (n=12/group): OGD, normoxic (normal physiological conditions), OGD with 100 nM H2 relaxin and OGD with 100 nM H3 relaxin. Eight brain slices from each treatment group were removed from culture at 8 hours and 12 hours post-treatment to be used in the cell death detection ELISA. The remaining four slices per treatment group were removed at 8 hours post-treatment and were fixed and processed for caspase-3 immunostaining. We found that there was no significant reduction in the degree of apoptosis following treatment with xi either relaxin. These findings suggest that relaxins are not inhibiting apoptosis under the conditions of this experiment. It is possible that neuroprotective effects of relaxin may occur earlier during periods of ischemia. As single doses of relaxin were used in this study, it is also possible that higher doses of either peptide may have inhibited apoptosis.

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https://scholar.acadiau.ca/islandora/object/theses:969