The Effects of Umbilical Cord Mesenchymal Stem Cells on Traumatic Pancreatitis in Rats

OBJECTIVE

This study explored the therapeutic and protective effects of umbilical cord mesenchymal stem cells (ucMSCs) on traumatic pancreatitis (TP) to provide a theoretical basis for TP treatment with MCSs by establishing a TP rat model.

METHODS

We used 60 healthy adult male Sprague Dawley (SD) rats to create four experimental groups: sham, ucMSC control, TP, and ucMSC treatment. We observed ucMSC homing in the rats by fluorescence microscopy and assessed the degree of pancreatic tissue injury by hematoxylin and eosin (HE) staining on days 1, 3, and 7 after transplantation. Furthermore, we used an in vivo imaging system to evaluate the localization of cell membrane-stained ucMSCs in rats with TP. Finally, we measured the serum levels of amylase, lipase, pro-and anti-inflammatory factors, and oxidative stress factors by enzyme-linked immunosorbent assay (ELISA).

RESULTS

The pancreatic histopathological score and the serum amylase and lipase levels were lower in the ucMSC treatment group than in the TP group (P < 0.05). Interleukin (IL)-6, tumor necrosis factor-α (TNF-α), and oxidase malondialdehyde (MOD) levels were significantly higher in the ucMSC treatment group than in the TP group. However, IL-10, transforming growth factor-β, and superoxide dismutase (an antioxidant enzyme, SOD) levels were significantly higher in the ucMSC treatment group than in the TP group (P < 0.05).

CONCLUSION

ucMSCs can migrate and implant in injured areas of the pancreas in rats. Furthermore, they participate in pancreatic tissue repair and regulate immunity by inhibiting the systemic inflammatory response and oxidative stress.

Human umbilical cord mesenchymal stem cells-derived exosomes for treating traumatic pancreatitis in rats

Background

The therapeutic and protective effects of human umbilical cord mesenchymal stem cells-exosomes (hucMSC-Exs) on traumatic pancreatitis (TP) remain unknown. Here, we established a rat model of TP and evaluated and compared the therapeutic effects of hUC-MSCs and hucMSC-Exs.

Methods

HucMSC-Exs were obtained by ultracentrifugation and identified using transmission electron microscopy and western blot analysis. TP rats were treated by tail vein injection of hUC-MSCs and hucMSC-Exs. Their homing in rats was observed by performing fluorescence microscopy. The degree of pancreatic tissue damage was assessed by HE staining, the expression levels of amylase, lipase, and inflammatory cytokines were detected by ELISA, apoptosis was detected by TUNEL assay, and the expression levels of various apoptosis-related proteins were detected by western-blot. The expression levels of apoptosis-related molecular markers were detected by RT-qPCR.

Results

The colonization of exosomes was observed in pancreatic tissue. Compared to TP group, the histopathological score of pancreas was significantly decreased in the TP + hUC-MSCs group and TP + hucMSC-Exs group (P < 0.05). Compared to TP group, the activity of serum amylase and lipase was significantly decreased (P < 0.05). The expression levels of IL-6 and TNF-α were significantly decreased, while those of IL-10 and TGF-β were significantly increased (P < 0.05). The apoptosis index of the TP group was significantly increased (P < 0.05), whereas that of the TP + hUC-MSCs and TP + hucMSC-Exs groups was significantly decreased (P < 0.05). Compared to TP group, the expression levels of Bax, Bcl-2, and Caspase-3 were significantly decreased in the TP + hUC-MSCs group and TP + hucMSC-Exs group (P < 0.05).

Conclusion

HucMSC-Exs can colonize injured pancreatic tissue, inhibit the apoptosis of acinar cells, and control the systemic inflammatory response to facilitate the repair of pancreatic tissue.

Enhancing or inhibiting apoptosis? The effects of ucMSC-Ex in the treatment of different degrees of traumatic pancreatitis

The animal models of traumatic pancreatitis (TP) were established to evaluate the specific mechanisms by which umbilical cord mesenchymal stem cell-derived exosomes (ucMSC-Ex) exert therapeutic effects. Sixty four rats were randomly divided into eight groups, including TP groups with three different degrees and relevant groups with ucMSC-Ex treated. The degrees of pancreatic tissue injury were evaluated by Histological Examination. Furthermore, enzyme-linked immunosorbent assay were applied to evaluate the activity of pancreatic enzymes and levels of inflammatory factors in serum. Finally, the apoptotic effects of each group were evaluated by TUNEL, western blot (WB), and real time fluorescence quantitative polymerase chain reaction (RT-qPCR). The pancreatic histopathological score and serum amylase and lipase levels gradually increased in various degrees of TP and the levels in the treatment group were all significantly decreased. The apoptosis index gradually increased in each TP group and significantly decreased in the treatment group in TUNEL results. WB and RT-qPCR showed the same trend, that bax and caspase-3 gradually increased and bcl-2 gradually decreased in TP groups. Compared with TP groups, the expression of bax and caspase-3 were lower while bcl-2 expression was higher in the treatment group. ucMSC-Ex suppressed the inflammatory response and inhibited pancreatic acinar cell apoptosis to promote repair of injured pancreatic tissue.

Traumatic pancreatitis

Post-traumatic pancreatitis can develop secondary to blunt or penetrating abdominal trauma, post-endoscopic retrograde cholangiopancreatography, or following pancreatic surgery. Clinical findings are often nonspecific, and imaging findings can be subtle on presentation. Early diagnosis of pancreatic duct injury is critical and informs management strategy; imaging plays important role in diagnosis of ductal injury and identification of delayed complications such as retroperitoneal fluid collections, pancreatic fistula, ductal strictures, and recurrent pancreatitis. Delayed diagnosis of pancreatic injury is associated with high mortality and morbidity, and therefore, heightened clinical suspicion is important in order for the radiologist to effectively impact patient care. There are accepted scoring systems for classification of post-traumatic pancreatic injuries and these should be included in radiology reports. Pancreatitis following ERCP appears similar on imaging to other causes of acute pancreatitis unless concomitant perforation occurs. Postoperative pancreatitis may be difficult to diagnose given associated or overlapping expected postoperative findings. Postoperative pancreatic fistulas typically arise from either a leaking pancreatic resection surface or the pancreatoenteric anastomosis and are more common in patients with a "soft" pancreas. Preoperative imaging biomarkers like duct diameter, pancreatic glandular steatosis and parenchymal fibrosis can help predict risk of development of postoperative pancreatic fistula. This review will illustrate the imaging features and the most important imaging findings in patients with post-traumatic pancreatitis.