Mesoporous Se@SiO₂ Nanoparticles-coated Catheter Promotes Prostatic Urethra Wound Healing And Suppresses Fibrosis By Modulating Reactive Oxygen Species（ROS）-P38 MAPK Pathway

Objective:The purpose of this study is to prepare m Se@SiO₂NPs,a new type of nanoparticles with SiO₂ as a carrier and antioxidant Selenium,and coat it on the catheter after prostate surgery,so as to promote postoperative wound repair and reduce fibrosis.Methods:Part I:m Se@SiO₂ NPs is prepared using the"thermal injection method"and"one-pot method"with chitosan/acetic acid as the solvent,and its structure,morphology,particle size,and in vitro release characteristics were tested.Then,it is applied to the specially treated urinary catheter.Part II:Establish a TURP model of beagle dogs and randomly divide them into 3 groups.After operation,catheters coated with physiological saline,SiO₂ nanospheres,and m Se@SiO₂ NPs were indwelled.Cystoscopy and H&E staining of the prostate wound tissue were applied to observe the repair of the urethral wound of the prostate through each postoperative time point.Masson’s staining was performed to observe the fibrosis degree of wound repair at each time point,and the proliferation and activation status of stromal fibroblasts at different time points were detected by immunofluorescence staining.Part III:verify the safety and oxidation resistance of the nanoparticles in the wound tissues and cell lines.The safe concentration range of m Se@SiO₂ NPs was detected by CCK-8 experiment,the distribution of sustained-release Selenium on the wound and major organs was analyzed by ICP-AES,and the blood samples of Beagle dogs of the experimental group were collected for liver and kidney function detection to verify its safety,DCFH-DA was used to detect the oxidative stress level.Part IV:PBS,SiO₂,Se@SiO₂,H₂O₂,H₂O₂+Se@SiO₂ was incubated with the prostate fibroblasts respectively,and then we checked the oxidative stress levels and fibrosis markers of each group by q PCR and Western bolt.Various functional experiments were conducted to verify the proliferation and migration capabilities.Finally,Western blot and immunofluorescence were used to detect the activation of the p38 MAPK signaling pathway in each group.Results:Part I:m Se@SiO₂ NPs were successfully prepared.TEM detection showed spherical appearance,uniform size and dispersion,suitable particle size,and XRD detection showed consistent phase.The nanoparticle has a good sustained-release effect and is coated on a specially treated urinary catheter to obtain the coating material for the experiment.Part II:the TURP model of beagle dog and postoperative indwelling catheter model were successfully established.At each time point after the operation,the wound repair rate and re-epithelialization in the prostatic urethra of the m Se@SiO₂ NPs group were both better than other groups,and the number of myofibroblasts expressingα-SMA was significantly reduced.Part III:No Selenium distribution was detected in other major organs of the beagles in the m Se@SiO₂ NPs group at each time point,while the Selenium content in the wound tissues remained stable and within the range of biosafety concentration,and there was no difference in liver and kidney function and histology of the major organs in the beagles in each group.ROS levels in the m Se@SiO₂ NPs group were reduced in both the Beagle wound tissue and the fibroblast oxidative stress model.Part IV:Previous studies have shown that ROS is one of the influencing factors of fibroblast activation.The experimental results showed that while the m Se@SiO₂ NPs inhibited oxidative stress,the expression levels of markers of activation and related proteins of prostate fibroblasts were also decreased.However,the m Se@SiO₂ NPs could still promote the proliferation and migration of prostate matrix fibroblasts.Further experimental results showed that the m Se@SiO₂NPs could inhibit the activation of the P38 MAPK signaling pathway induced by oxidative stress.Conclusion:In this study,m Se@SiO₂ NPs with chitosan/acetic acid as a coated carrier were successfully prepared.Indwelling a catheter coated with porous Se@SiO₂nanospheres after TURP can promote postoperative wound repair of prostatic urethra,accelerate the process of wound re-epithelialization,and significantly reduce the degree of fibrosis in the wound tissue.By inhibiting the oxidative stress-induced P38 MAPK signaling pathway,m Se@SiO₂ NPs promoted the proliferation and migration of stromal fibroblasts,thus promoting the postoperative wound repair of prostate.The m Se@SiO₂ NPs coated catheter provides a new idea and strategy for improving the effect of prostate surgery which is expected to replace the common urethral catheter after prostate surgery to promote anti-fibrotic wound repair in the prostatic urethra and the incidence of postoperative complications.