Mesenchymal stem cells (MSCs) are considered as promising therapeutic agents for neurodegenerative disorders because they can reduce underlying pathology and also repair damaged tissues. Regarding the delivery of MSCs into the brain, intravenous and intra-arterial routes may be less feasible than intraparenchymal and intracerebroventricular routes due to the blood–brain barrier. Compared to the intraparenchymal or intracerebroventricular routes, however, the intrathecal route may have advantages: this route can deliver MSCs throughout the entire neuraxis and it is less invasive since brain surgery is not required. The objective of this study was to investigate the distribution of human Wharton’s jelly-derived MSCs (WJ-MSCs) injected via the intrathecal route in a rat model. WJ-MSCs (1 × 106) were intrathecally injected via the L2-3 intervertebral space in 6-week-old Sprague Dawley rats. These rats were then sacrificed at varying time points: 0, 6, and 12 h following injection. At 12 h, a significant number of MSCs were detected in the brain but not in other organs. Furthermore, with a 10-fold higher dose of WJ-MSCs, there was a substantial increase in the number of cells migrating to the brain. These results suggest that the intrathecal route can be a promising route for the performance of stem cell therapy for CNS diseases.

Purpose: The purpose of this study was to elucidate whether contrast-enhanced ultrasonography (CEUS) can visualize orally administered Sonazoid leaking into the peritoneal cavity in a postoperative stomach leakage mouse model.Methods: Adult female mice (n=33, 9-10 weeks old) were used. Preoperative CEUS was performed after delivering Sonazoid via intraperitoneal injection and the per oral route. A gastric leakage model was then generated by making a surgical incision of about 0.5 cm at the stomach wall, and CEUS with per oral Sonazoid administration was performed. A region of interest was drawn on the CEUS images and the signal intensity was quantitatively measured. Statistical analysis was performed using a mixed model to compare the signal intensity sampled from the pre-contrast images with those of the post-contrast images obtained at different time points.Results: CEUS after Sonazoid intraperitoneal injection in normal mice and after oral administration in mice with gastric perforation visualized the contrast medium spreading within the liver interlobar fissures continuous to the peritoneal cavity. A quantitative analysis showed that in the mice with gastric perforation, the orally delivered Sonazoid leaking into the peritoneal cavity induced a statistically significant (P<0.05) increase in signal intensity in all CEUS images obtained 10 seconds or longer after contrast delivery. However, enhancement was not observed before gastric perforation surgery (P=0.167).Conclusion: CEUS with oral Sonazoid administration efficiently visualized the contrast medium spreading within the peritoneal cavity in a postoperative stomach leakage mouse model.

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