An experimental study on preventive effect of continuous irrigation from peridural adhesion after laminectomy

Objective To observe the preventive effect of continuous irrigation with sodium hyaluronate injection from peridural adhesionaminectomy.Methods Larninectomies were performed in L1,L4,L7 of 25 New Zealand rabbits respectively with 3

Prevention strategies of postoperative adhesion in soft tissues by applying biomaterials:Based on the mechanisms of occurrence and development of adhesions

Postoperative adhesion(POA)widely occurs in soft tissues and usually leads to chronic pain,dysfunction of adjacent organs and some acute complications,seriously reducing patients’quality of life and even being life-threatening.Except for adhesiolysis,there are few effective methods to release existing adhesion.However,it requires a second operation and inpatient care and usually triggers recurrent adhesion in a great incidence.Hence,preventing POA formation has been regarded as the most effective clinical strategy.Biomaterials have attracted great attention in preventing POA because they can act as both barriers and drug carriers.Nevertheless,even though much reported research has been demonstrated their efficacy on POA inhibition to a certain extent,thoroughly preventing POA formation is still challenging.Meanwhile,most biomaterials for POA prevention were designed based on limited experiences,not a solid theoretical basis,showing blindness.Hence,we aimed to provide guidance for designing anti-adhesion materials applied in different soft tissues based on the mechanisms of POA occurrence and development.We first classified the postoperative adhesions into four categories according to the different components of diverse adhesion tissues,and named them as“membranous adhesion”,“vascular adhesion”,“adhesive adhesion”and“scarred adhesion”,respectively.Then,the process of the occurrence and development of POA were analyzed,and the main influencing factors in different stages were clarified.Further,we proposed seven strategies for POA prevention by using biomaterials according to these influencing factors.Meanwhile,the relevant practices were summarized according to the corresponding strategies and the future perspectives were analyzed.

A sandwiched patch toward leakage-free and anti-postoperative tissue adhesion sealing of intestinal injuries

Ideal repair of intestinal injury requires a combination of leakage-free sealing and postoperative antiadhesion.However,neither conventional hand-sewn closures nor existing bioglues/patches can achieve such a combination.To this end,we develop a sandwiched patch composed of an inner adhesive and an outer antiadhesive layer that are topologically linked together through a reinforced interlayer.The inner adhesive layer tightly and instantly adheres to the wound sites via-NHS chemistry;the outer antiadhesive layer can inhibit cell and protein fouling based on the zwitterion structure;and the interlayer enhances the bulk resilience of the patch under excessive deformation.This complementary trilayer patch(TLP)possesses a unique combination of instant wet adhesion,high mechanical strength,and biological inertness.Both rat and pig models demonstrate that the sandwiched TLP can effectively seal intestinal injuries and inhibit undesired postoperative tissue adhesion.The study provides valuable insight into the design of multifunctional bioadhesives to enhance the treatment efficacy of intestinal injuries.

CATase-immobilized hydrogel platform molded by photo-enzyme coupling polymerization for effectively preventing postoperative abdominal adhesion

Redox homeostasis,which is regulated by enzymes acting as regulatory valves,is crucial for maintaining the proper functioning of biomolecules and a stable microenvironment for physiological processes by modulating the homeostasis of reactive oxygen species(ROS).Antioxidant enzymes in biocatalysis are used in the prevention or treatment of oxidative stress-related disease by counteracting the harmful effects of ROS.However,designing a system that can efficiently immobilize antioxidant enzymes with high catalytic activity and stability is still challenging.Bioinspired by photo-biocatalysis,a novel and effective catalase(CATase)-immobilized hydrogel platform has been developed by the proposed photo-enzymatic coupled radical polymerization strategy of the visible light coupling with the porphyrin-centered CATase.The higher catalytic stability and activity can therefore be achieved due to the preferential polymerization of CATase-immobilized hydrogel platform with a favorable three-dimensional network of enhanced coupling efficacy between light and enzymes.The mechanisms of free radical-initiated polymerization as well as the antioxidant cycle in the photo-CATase coupling system have been explored.Intriguingly,the CATase-immobilized hydrogel platform affords an unprecedented antioxidant ability to scavenge ROS and provide an effective cellular protection mechanism against external oxidative stress.Additionally,the CATase-immobilized hydrogel platform can effectively prevent peritoneal adhesion by reducing the expression of inflammatory cytokines.Therefore,the novel CATase-immobilized hydrogel platform is a potential candidate for physical barriers that effectively prevent postoperative adhesion formation,offering a new anti-adhesion strategy for clinical applications.

Use of N,O-carboxymethyl chitosan to prevent postsurgical adhesions in a rabbit double uterine horn model： a randomized controlled design

In previous studies, N,O-carboxymethyl chitosan has been shown to decrease the incidence and intensity of abdominal adhesions. In the present study, adhesions were induced in 220 rabbits using a double uterine horn model. Rabbits were randomized to receive an operation only or an operation+medical chitosan intraperitoneally. Twenty-two rabbits from each group were euthanized at one of five different times(Day 3, 7, 14, 28, or 42), and adhesion formation was given gross and histopathological scores. Reductions were observed in adhesion extent(P=0.0337) and tenacity(P=0.0271) as well as inflammation(P<0.0001) on Day 3 when medical chitosan was applied. Prior to Day 14, fibrosis was less obvious in the medical chitosan group(P<0.0005). The tenacity scores were significantly lower in the medical chitosan group following Day 14(P<0.05), while the type scores were lower in the medical chitosan group following Day 28(P<0.03). Thus, medical chitosan decreased both the gross and the histopathological scores of the induced adhesions.

Bottlebrush inspired injectable hydrogel for rapid prevention of postoperative and recurrent adhesion

Postsurgical adhesion is a common clinic disease induced by surgical trauma,accompanying serious subsequent complications.Current non-surgical approaches of drugs treatment and biomaterial barrier administration only show limited prevention effects and couldn’t effectively promote peritoneum repair.Herein,inspired by bottlebrush,a novel self-fused,antifouling,and injectable hydrogel is fabricated by the free-radical polymerization in aqueous solution between the methacrylate hyaluronic acid(HA-GMA)and N-(2-hydroxypropyl)methacrylamide(HPMA)monomer without any chemical crosslinkers,termed as H-HPMA hydrogel.The H-HPMA hydrogel can be tuned to perform excellent self-fused properties and suitable abdominal metabolism time.Intriguingly,the introduction of the ultra-hydrophilic HPMA chains to the H-HPMA hydrogel affords an unprecedented antifouling capability.The HPMA chains establish a dense hydrated layer that rapidly prevents the postsurgical adhesions and recurrent adhesions after adhesiolysis in vivo.The H-HPMA hydrogel can repair the peritoneal wound of the rat model within 5 days.Furthermore,an underlying mechanism study reveals that the H-HPMA hydrogel significantly regulated the mesothelial-to-mesenchymal transition(MMT)process dominated by the TGF-β-Smad2/3 signal pathway.Thus,we developed a simple,effective,and available approach to rapidly promote peritoneum regeneration and prevent peritoneal adhesion and adhesion recurrence after adhesiolysis,offering novel design ideas for developing biomaterials to prevent peritoneal adhesion.

Biomimetic hybrid hydrogel for hemostasis,adhesion prevention and promoting regeneration after partial liver resection

Partial liver resection is an established treatment for hepatic disorders.However,surgical bleeding,intra-abdominal adhesion and rapid liver regeneration are still major challenges after partial liver resection,associated with morbidity and mortality.Herein,a biomimetic hybrid hydrogel,composed of oxidized hyaluronic acid,glycol chitosan and MenSCs-derived conditioned medium(CM),is presented to address these issues.The hybrid hydrogel is formed through reversible Schiff base,and possesses injectability and self-healing capability.Moreover,hybrid hydrogel exhibits the capabilities of hemostasis,anti-infection,tissue adhesion and controllable release of cargoes.Based on in vivo studies of the multifunctional hybrid hydrogel,it is demonstrated that acute bleeding in partial liver resection can be ceased immediately by virtue of the hemostasis features of hybrid hydrogel.Also,a significant reduction of intra-abdominal adhesion is confirmed in hybrid hydrogel-treated resection surface.Furthermore,upon the treatment of hybrid hydrogel,hepatic cell proliferation and tissue regeneration can be significantly improved due to the controllably released cytokines from MenSCs-derived CM,exerting the effects of mitogenesis and anti-inflammation in vivo.Thus,the biomimetic hybrid hydrogel can be a promising candidate with great potential for application in partial liver resection.