Effects of Lipopolysaccharide Immune Challenge on Microglial Activation and CD3+ T-cells in the Substantia Nigra of Female Rats (2023)
Undergraduates: Zhuo Yun Song, Mary Linares, Sean Ahaotu-Simelane, Phoebe Pak, Samanyu Kunchanapalli
Faculty Advisor: Shveta Parekh
Department: Psychology & Neuroscience
Parkinson’s Disease (PD) is a prolific and debilitating motor disorder whose mechanism is not well understood. However, immune dysfunction and neuroinflammation have been implicated in its etiology. In exploring the action of the immune system in brain regions associated with the disease, we hope to uncover more of the neuroimmunological mechanism of PD. Previous research suggests that disequilibrium in the function of microglia and T-cell infiltration are predictors of onset of PD. This can be caused by age and chronic stress as well as inflammation from functional and morphological change in microglia. Although previous evidence points to an association between T-cell, microglia, and their individual roles in the development of PD, minimal literature has analyzed how activated microglia and T-cells work in conjunction to influence PD. The current study aims to find a relationship between activated microglia and CD3+ T-cells and their combined role in PD pathology. While CD4+ and CD8+ T-cells have been analyzed in literature involving PD pathology, studies seldom examined CD3+ T-cells. By examining CD3+ cells, we can potentially offer new insight to the existing evidence of T-cells in PD pathology. Moreover, the use of female animals in neuroscience research has remained low thus far. Therefore, the central question explores the association between the presence of T-cells and activated microglia in the substantia nigra of female rat brains following lipopolysaccharide (LPS) challenge. Since activated microglia may cause T-cell infiltration into the substantia nigra, we hypothesize that there will be higher CD3+ expression colocalized near the activated microglia compared to the control. Saline injected and LPS challenged brain slices underwent Iba-1 and CD3+ immunohistochemistry staining to detect the presence of microglia and CD3+ T-cells. The substantia nigra was imaged via widefield and confocal microscopy. We found that LPS challenged rats had greater process length compared to the control. However, no difference was detected in soma size between LPS and saline rats.
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