Thermoresponsive polysaccharide-based composite hydrogel with antibacterial and healing-promoting activities for preventing recurrent adhesion after adhesiolysis.

Postoperative adhesions are very common complications after general abdominal surgery. Although adhesiolysis has been proven effective in eliminating the preexisting adhesions, the new trauma caused by surgical lysis can induce recurrent adhesion. The prevention of recurrent adhesion after adhesiolysis is more difficult because the injury is more severe and adhesion mechanism is more complicated compared with the primary adhesion. In this study, a thermoresponsive hydrogel contained galactose modified xyloglucan (mXG) and hydroxybutyl chitosan (HBC) was developed as a barrier device for recurrent adhesion prevention after adhesiolysis due to its injectability and spontaneous gelling behaviors at the body temperature without any chemical reactions or extra driving factors. First, mXG and HBC were synthesized via enzymatic modification and etherification reaction, respectively. Rheological measurements indicated that the mXG/HBC composite system showed excellent thermosensitivity properties, and their gelation temperature and time can be modulated via adjusting the mXG/HBC ratio. Moreover, the mXG/HBC hydrogel exhibited excellent cytocompatibility and hemocompatibility in vitro. Furthermore, the mXG/HBC hydrogel could promote wound healing in the rat skin wound model. Finally, the efficacy of the mXG/HBC composite hydrogel in the prevention of recurrent adhesion was evaluated in a more rigorous rat repeated-injury adhesion model. The results demonstrated that the composite hydrogel could not only effectively prevent recurrent adhesion after adhesiolysis, but also promote wound healing and reduce scare formation. These results suggested that the mXG/HBC composite hydrogel may be a promising candidate as an injectable anti-adhesion system for clinical applications. STATEMENT OF SIGNIFICANCE: Although adhesiolysis has been proven effective in eliminating the preexisting adhesions, the new trauma caused by surgical lysis can induce recurrent adhesion. So far, most of the existing barrier systems and pharmacological approaches were developed for primary adhesion prevention while few attention has paid on prevention of recurrent adhesion after adhesiolysis. In the present study, we developed a thermoresponsive polysaccharide-based composite hydrogel by simple mixing galactose modified xyloglucan (mXG) and hydroxybutyl chitosan (HBC). The resulting mXG/HBC composite hydrogel not only was easy to handle and highly effective in preventing the recurrent adhesion after adhesiolysis, but also could promote wound healing and reduce scare formation. Our study provide an effective anti-adhesion system for preventing recurrent adhesion after adhesiolysis.

Preventive effect of MXG hycrogel on recurrent adhesion between abdominal wall and cecum and its influence in expressions of TGF-β1 and CTGF in rats / 吉林大学学报(医学版)

Objective: To evaluate the anti-adhesion properties of xyloglucan (mXG) hydrogel in the L929 mouse fibroblasts, to establish the animal model of recurrent adhesion in the rats after adhesionlysis, and to investigate the prevention effect of mXG hydrogel in recurrent adhesion and its influence in the expressions of transforming growth factor-β1 (TGF-β1) and connective tissue growth factor (CTGF). Methods: After seeding on the surface of mXG gel, the adhesion property of L929 mouse fibroblasts was detected with fluorescence staining. The rat models of recurrent adhesion were established after adhesionlysis. Fourty-eight SD rats were randomly divided into 3 groups respectively (n=16). In adhesion group, 1 mL saline was injected into the abdominal wall and cecum of the rats; in commercial membrane group, the 2 cm × 3 cm chitosan anti-adhesion membrane was used to cover the wound of abdominal wall of the rats; in mXG hydrogel group, 1 mL 4% mXG hydrogel was injected into the abdominal wall and cecal wound of the rats, and abdominal surgery was ended after the complete formation of the hydrogel (3 min). Eight rats were killed in each group 7 and 14 d after the second operation, and the degrees of adhesion were evaluated and the histological changes were observed. Immunohistochemical staining was used to observe the expression levels of CTGF and TGF-β1. Results: A large number of L929 mouse fibroblasts proliferated well and exhibited a spherical morphology in control group; but in mXG hydrogel group, only very little L929 mouse fibroblasts were globular, showing the mXG hydrogel had good resistance to the adhesion of L929 mouse fibroblasts. Blunt separate adhesion surface formed in all of the rats after operation. 7 d after the second operation, 4-5 score adhesion with fibrous connective tissue hyperplasia formed in adhesion group; moderate adhesion formed in commercial membrane group with more connective tissue; most cecum and abdominal wall began to heal in mXG hydrogel group with less connective tissue. 14 d after the second operation, more severe peritoneal adhesions presented in adhesion group with proliferated fiber connetive tissue and collegan; severe adhesions also presented in commercial membrane group; mild adhesion was found in two rats mXG group, the other rats had no adhesion, and the defects were almost completely recovered. On days 7 and 14 after the second operation, the mean adhesion score of the rats in mXG group was significantly lower than those in adhesion group and commercial membrane group (P<0.05). The expression levels of TGF-βl and CTGF were increased with the increase of peritoneal adhesion scores and collagen deposition; the expression levels of TGF-βl and CTGF were the highest in adgesion group and the lowest in mXG group. Conclusion: mXG hydrogels have good resistance to fibroblast adhesion, and mXG hydrogel is effective in reducing the formation of recurrent adhesion in the rats after adhesionlysis and can decrease the expression levels of adhesion-related factors TGF-βl and CTGF.

Preventive effect of MXG hycrogel on recurrent adhesion between abdominal wall and cecum and its influence in expressions of TGF-β1 and CTGF in rats / 吉林大学学报(医学版)

Objective:To evaluate the anti-adhesion properties of xyloglucan(mXG)hydrogel in the L929 mouse fibroblasts,to establish the animal model of recurrent adhesion in the rats after adhesionlysis,and to investigate the prevention effect of mXG hydrogel in recurrent adhesion and its influence in the expressions of transforming growth factor-β1(TGF-β1)and connective tissue growth factor(CTGF).Methods:After seeding on the surface of mXG gel,the adhesion property of L929 mouse fibroblasts was detected with fluorescence staining.The rat models of recurrent adhesion were established after adhesionlysis.Fourty-eight SD rats were randomly divided into 3 groups respectively(n=16).In adhesion group,1 mL saline was injected into the abdominal wall and cecum of the rats;in commercial membrane group,the 2 cm×3 cm chitosan anti-adhesion membrane was used to cover the wound of abdominal wall of the rats;in mXG hydrogel group,1 mL 4% mXG hydrogel was injected into the abdominal wall and cecal wound of the rats,and abdominal surgery was ended after the complete formation of the hydrogel(3 min).Eight rats were killed in each group 7 and 14 d after the second operation,and the degrees of adhesion were evaluated and the histological changes were observed. Immunohistochemical staining was used to observe the expression levels of CTGF and TGF-β1.Results:A large number of L929 mouse fibroblasts proliferated well and exhibited a spherical morphology in control group;but in mXG hydrogel group,only very little L929 mouse fibroblasts were globular,showing the mXG hydrogel had good resistance to the adhesion of L929 mouse fibroblasts.Blunt separate adhesion surface formed in all of the rats after operation.7 d after the second operation,4-5 score adhesion with fibrous connective tissue hyperplasia formed in adhesion group;moderate adhesion formed in commercial membrane group with more connective tissue;most cecum and abdominal wall began to heal in mXG hydrogel group with less connective tissue.14 d after the second operation,more severe peritoneal adhesions presented in adhesion group with proliferated fiber connetive tissue and collegan;severe adhesions also presented in commercial membrane group;mild adhesion was found in two rats mXG group,the other rats had no adhesion,and the defects were almost completely recovered.On days 7 and 14 after the second operation,the mean adhesion score of the rats in mXG group was significantly lower than those in adhesion group and commercial membrane group(P<0.05).The expression levels of TGF-β1 and CTGF were increased with the increase of peritoneal adhesion scores and collagen deposition;the expression levels of TGF-β1 and CTGF were the highest in adgesion group and the lowest in mXG group.Conclusion:mXG hydrogels have good resistance to fibroblast adhesion,and mXG hydrogel is effective in reducing the formation of recurrent adhesion in the rats after adhesionlysis and can decrease the expression levels of adhesion-related factors TGF-β1 and CTGF.