title: The histopathological and morphometric investigation of the effects of systemically administered humic acid on alveolar bone loss in ligature-induced periodontitis in rats.
abstract: BACKGROUND
  Humic acid is a soil extract found widely around the world. This product includes some trace elements important for human's health. The purpose of this study was to evaluate the morphometric and histopathological changes associated with an experimental periodontitis model in rats in response to systemic administration of humic acid.
  
  
  METHODS
  Thirty-eight male Wistar rats were divided into five experimental groups: non-ligated (NL, n = 6) group; ligature-only (LO, n = 8) group; ligature + systemic administration of humic acid (20, 80 and 150 mg/kg body weight per day for 15 d respectively) (S-20, S-80 and S-150) groups. 4/0 silk ligatures were placed at the gingival margin of lower first molars of the mandibular quadrant. The animals were killed at the end of 15 d. Changes in alveolar bone levels were clinically measured, using a stereomicroscope (× 25), as the distance from the cementoenamel junction to the alveolar bone crest. Tissues were histopathologically examined to assess the differences of osteoclast numbers, osteoblastic activity and inflammatory cell infiltration among the study groups. Enzyme-linked immunosorbent assay interleukin (IL)-1β and IL-10 levels in serum and gingival homogenates were evaluated.
  
  
  RESULTS
  At the end of 15 d, the alveolar bone loss was significantly higher in the LO group compared to the NL, S-80 and S-150 groups (p < 0.05). In addition, the alveolar bone loss in the S-80 group was significantly lower than the LO and S-20 groups (p < 0.05). The osteoblastic activity in the S-80 and S-150 groups was significantly higher than the other groups (p < 0.05). The osteoclast number in the LO group was significantly higher than the NL, S-80 and S-150 groups (p < 0.05). Inflammatory cell infiltration was significantly higher in LO and S-20 groups than the other groups (p < 0.05). The highest serum and gingival homogenate IL-10 levels were determined in the S-80 group (p < 0.05). The serum and gingival homogenate IL-1β levels in the LO group were significantly higher than the other groups (p < 0.05). Both 80 and 150 mg/kg dosages of humic acid significantly reduced the periodontitis-related bone loss and inflammation, but the differences between these two groups were not statistically significant (p > 0.05).
  
  
  CONCLUSIONS
  Within the limits of this study, it can be suggested that humic acid, when administered systemically as an 80 mg/kg dose, may prevent alveolar bone loss and reduce inflammation in the rat model.
authors.affiliation: Department of Periodontology, Faculty of Dentistry, Adıyaman University, Adıyaman, Turkey.
authors.forename: M
authors.initials: M
authors.lastname: Çalışır
authors.affiliation: Department of Periodontology, Faculty of Dentistry, Cumhuriyet University, Sivas, Turkey.
authors.forename: A
authors.initials: A
authors.lastname: Akpınar
authors.affiliation: Department of Microbiology, Faculty of Medicine, Cumhuriyet University, Sivas, Turkey.
authors.forename: Ö
authors.initials: Ö
authors.lastname: Poyraz
authors.affiliation: Department of Pathology, Faculty of Medicine, Cumhuriyet University, Sivas, Turkey.
authors.forename: F
authors.initials: F
authors.lastname: Göze
authors.affiliation: Department of Biostatistics, Faculty of Medicine, Cumhuriyet University, Sivas, Turkey.
authors.forename: Z
authors.initials: Z
authors.lastname: Çınar
mesh_terms: D016301:Alveolar Bone Loss / Q000473:pathology / Q000517:prevention & control*; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use*; D004195:Disease Models, Animal; D005881:Gingiva / Q000737:chemistry; D006812:Humic Substances; D007249:Inflammation / Q000188:drug therapy; D016753:Interleukin-10 / Q000032:analysis / Q000097:blood; D053583:Interleukin-1beta / Q000032:analysis / Q000097:blood; D008026:Ligation; D008297:Male; D008963:Molar / Q000473:pathology; D010518:Periodontitis / Q000150:complications / Q000188:drug therapy* / Q000473:pathology; D051381:Rats; D017208:Rats, Wistar
chemical_list: D000893:Anti-Inflammatory Agents; D006812:Humic Substances; C000594089:IL1B protein, rat; D053583:Interleukin-1beta; D016753:Interleukin-10
keywords: alveolar bone loss; experimental periodontitis; humic acid; inflammatory cytokines