Establishment and evaluation of rat models of parastomal hernia

PURPOSE

Parastomal hernia poses a challenging problem in the field of hernia surgery. The high incidence and recurrence rates of parastomal hernia necessitate surgeons to enhance surgical techniques and repair materials. This study aimed to develop a rat model of parastomal hernia by inducing various types of defects on the abdominal wall with colostomy. This established method has potential for future studies on parastomal hernia.

METHODS

In this study, 32 male rats were included and randomly divided into four groups: the oblique abdominis excision (OE), oblique abdominis dissection (OD), rectus abdominis excision (RE), and rectus abdominis dissection (RD) groups. In each group, colostomy was performed and an abdominal wall defect was induced. The rats were observed for 28 days following surgery. The survival rate, body weight, parastomal hernia model scores, abdominal wall adhesion and inflammation, and collagen level in the hernial sac were compared.

RESULTS

No significant differences in survival rate and weight were observed among the four groups. The parastomal hernia model scores in the RE and RD groups were significantly higher than those in the OE and OD groups. The ratio of collagen I/III in the RE and RD groups was significantly lower than that in the OE and OD groups. Adhesion and inflammation levels were lower in the RE group than in the RD group.

CONCLUSION

Based on a comprehensive comparison of the findings, RE with colostomy emerged as the optimal approach for establishing parastomal hernia models in rats.

Liquid Nanoparticles for Nanocatalytic Cancer Therapy

Nanotechnology is revolutionizing cancer therapy, and catalyzes the emerging of ion-involved cancer-therapeutic modality, which unfortunately suffers from undesirable nanocarriers for efficient intracellular ion delivery. To radically extricate from this critical issue, the glutathione (GSH)-responsive organosilica network is employed to lock the liquid drops at the nanoscale via a general bottom-up strategy to achieve the systemic delivery of "ion drugs". In this work, a sulfate radical generation donor (Na2 S2 O8 ), as a paradigm "ion drug", is entrapped into this liquid nanoparticle for efficiently delivering to the tumor region. After further surface engineering with pH-responsive tannic acid-Fe2+ framework, these liquid nanoparticles achieve tumor-microenvironmental pH/GSH-dual responsive ion release (Fe2+ /Na+ /S2 O8 2- ) after reaching the tumor sites, where the Fe2+ further triggers S2 O8 2- to generate toxic •SO4 - and •OH, effectively executing cancer cell ferroptosis (Fe2+ , reactive oxygen species-ROS) and pyroptosis (Na+ , ROS). Such a tumor-responsive/specific liquid nanoplatform is highly instructive for further ion-mediated nanomedicine and disease treatment.