Role of nitric oxide-releasing compound in soft tissue regeneration and osteogenesis

Abstract

Purpose Tissue defects of the oral cavity are relatively common; however, its management is often challenging. Nitric oxide (NO)-releasing compound was reported to enhance wound healing by promoting re-epithelialization, angiogenesis, and osteoblast differentiation. The purpose of the study was to investigate the effects of NO-releasing compound in the tissue repair using synthetic agents and through in vitro and in vivo experiments. Materials and methods Synthetic NO-releasing compound consisting of pluronic F68, branched polyethylenimine and NONOates (FBN) was administrated in Porphyromas gingivalis (P. gingivalis) to evaluate antimicrobial effect. Also, scratch analysis was used to assess the migration of human gingival fibroblast-1 (HGF-1) treated with FBN. In vivo mouse experiments with a total of 33 BALB/C mice was performed to see effects of FBN on the mucosal defects of palate. To find the role of FBN in the repair of bone defect, 80 sprague-dawley rats with artificial calvarial defect were used in this study. Radiologic findings with micro-computed tomography (micro-CT) and histopathologic examination along with immunohistochemistry (IHC) were reviewed in vivo animal experiments.

Results Although direct bactericidal effect of pluronic F68-branched polyethylenimine (FB) was not observed, growth of P. gingivalis was inhibited by FB compared to control. Bacteriostatic and bactericidal effect were observed for FBN at a lower concentration than FB. Also, higher migration rate was found in HGF-1 treated with FBN, and wound size of the palate was significantly decreased in FBN treatment (all p < 0.05). According to immunohistochemical result, re-epithelialization and wound contraction tended to increase in the FBN-treated mucosal wounds. Bone volume and bone volume/tissue volume ratio were significantly higher among experimental groups treated with collagen sponges (p < 0.05). Immunohistochemical staining for CD31 and analysis of microvessel density (MVD) showed that angiogenesis was more prominent in the FBN-treated group.

Conclusions FBN exerted an antimicrobial effects and enhanced migration of HGF-1 cells and palatal mucosal healing. In calvarial defect, FBN was demonstrated to promote osteogenesis when applied in combination with a collagen sponge. These data suggest that FBN can be applied to ulcerative mucosal lesion and can be applied with collagen sponge to bone defect that are not amenable to bone grafts.

연구 목적 구강 내의 조직 결함은 흔히 접할 수 있지만, 치료에 종종 어려움을 겪는다. 일산화질소 복합체는 재상피화, 혈관 형성 및 조골세포 분화를 촉진함으로써 상처 치유를 향상시키는 것으로 보고되었다. 이 연구의 목적은 in vitro 실험과 in vivo 실험을 통해서, 합성된 일산화질소 복합체의 효과에 대하여 알아보는 것이다.

연구 방법 플루로닉 F68, 폴리에틸레니민 및 NONOates (FBN)로 합성된 일산화질소 복합체의 항균 효과를 평가하기 위해, FBN을 Porphyromas gingivalis (P. gingivalis)에 적용하였다. 또한 FBN으로 처리된 HGF-1의 이동을 평가하기 위해 스크래치 분석을 사용하였다. 구개 창상에서 FBN의 효과를 평가하기 위해 총 33마리의 BALB/C 생쥐를 사용하였다. 골결손부에서 FBN의 골재형성에 대한 역할을 평가하기 위해서, 두개골을 결손 시킨 총 80마리의 Spraque-Dawley 백서를 실험에 사용하였다. 동물 실험에서 조직학적 분석, 마이크로 CT 분석, 면역화학분석을 시행하였다.

연구 결과 플루로닉 F68-폴리에틸레니민 (FB)의 항균 작용은 관찰되지 않았지만, P. gingivalis의 증식을 막는 효과는 관찰되었다. FBN의 항균 및 정균 효과가 FB 보다 적은 농도에서 관찰되었다. 또한 FBN으로 처리된 HGF-1 세포에서 높은 이동률이 관찰되었고, FBN으로 처리된 군에서 상처 크기가 유의하게 감소하였다 (all p < 0.05). 면역화학염색에서 FBN으로 처리된 점막 상처에서 재상피화 및 상처 수축이 증가되었다. FBN과 콜라겐 스펀지를 적용한 실험 군에서 bone volume 및 bone volume/tissue volume이 현저히 높게 측정되었다 (p < 0.05). CD31의 면역화학염색과 미세혈관 밀도 분석 (microvessel density, MVD)에서, 혈관신생은 FBN으로 처리된 군에서 더 두드러지게 관찰되었다.

결론 FBN은 P. gingivalis에 대한 항균 효과가 나타났고, HGF-1의 이동과 구개 점막 치유를 향상시켰다. 두개골 연구에서, FBN은 콜라겐 스펀지와 함께 적용하였을 때, 골 형성 촉진 효과를 나타내었다. 따라서 FBN은 궤양성 구개 점막 병소와 골이식을 할 수 없는 골 결함 부위에 콜라겐 스펀지와 함께 적용될 수 있을 것으로 사료된다.