Analysis of respiratory movements in a mouse model of late Parkinson's disease submitted to stress

Parkinson's disease (PD) is known to cause tremor and rigidity, but other symptoms such as respiratory and autonomic dysfunctions are a major cause of disability and mortality in patients. In this study, we examined respiratory movements by using cineradiography on a murine model of late/advanced PD. Under surgical anesthesia, C57BL/6J mice received an injection of either 6-OHDA or vehicle solution to the right striatum. Two weeks after surgery, the animals had their respiratory movements recorded by video X-ray without any restraint. During recordings the animals were submitted to a mild acute-stress challenge. Behavioral tests were performed to assess the severity of the 6-OHDA lesion. As a result, behavioral tests confirmed severe motor impairments in 6-OHDA mice as compared to controls. 6-OHDA mice showed a predominantly thoracic respiratory pattern with reduced diaphragmatic excursion, and reduced respiratory frequency after stress. These results suggest that advanced nigrostrial degeneration may cause respiratory alterations with the features of obstructive-type respiratory disorders.