The biochemical effectiveness of N-acetylcysteine in experimental spinal cord injury in rats.

BACKGROUN

Therapeutic versus prophylactic plus therapeutic administration of omega-3 fatty acid on endotoxin-induced peridontitis in rats

PubMed ID: 15732866Background: The aim of the present study was 1) to evaluate the possible effects of therapeutic usage of omega-3 fatty acid on the gingival tissue levels of prostaglandin E2 (PGE2), prostaglandin F2? (PGF2?), platelet activating factor (PAF), and leukotriene B4 (LTB4) in endotoxin-induced periodontitis in rats and 2) to investigate whether prophylactic usage provides any additional benefits to therapeutic doses of omega-3 fatty acid. Methods: Experimental periodontitis was induced by repeated injection of Escherichia coli lipopolysaccharide (LPS). Thirty-six adult male Sprague-Dawley rats were divided into four study groups: 1) saline controls; 2) LPS; 3) therapeutic omega-3 fatty acid (TO3); and 4) prophylactic plus therapeutic omega-3 fatty acid (P + TO3) groups. In TO3 group, omega-3 fatty acid was given for 15 days following induction of experimental periodontitis. In P + TO3 group, omega-3 fatty acid was started 15 days before baseline, and then periodontitis was induced at baseline and omega-3 fatty acid was continued for 15 days after baseline. On day 15 after baseline, all rats were anesthetized and sacrificed. PGE2, PGF2?, and LTB4 levels in gingival tissue samples were analyzed by enzyme immunoassay and PAF levels were analyzed by radioimmonoassay. Data were evaluated statistically by using parametric tests. Results: LPS injection resulted in significant amount of bone loss (P <0.05). Neither therapeutic nor prophylactic plus therapeutic administration of omega-3 fatty acid with the doses and duration of therapy used in the present study was effective in preventing endotoxin-induced alveolar bone loss. TO3 group exhibited significant decreases in the gingival tissue levels of PGE2, PGF2?, LTB4, and PAF compared to the LPS group (P <0.05). PGE2 and PGF2? levels in TO3 group were similar to those of the saline group (P >0.05), while LTB4 and PAF levels were statistically higher than the saline group (P <0.05). Prophylactic plus therapeutic usage of omega-3 fatty acid provided similar levels of all these mediators to those of the saline controls (P >0.05). Conclusions: Therapeutic omega-3 fatty acid significantly reduced the gingival tissue levels of PGE2, PGF2?, LTB4, and PAF in experimental periodontitis. Furthermore, prophylactic usage of omega-3 fatty acid provided additional beneficial effects to the therapeutic administration by decreasing the gingival tissue levels of these mediators to levels of healthy tissue. These findings should be verified by longitudinal clinical trials investigating clinical and biochemical periodontal parameters to better define the possible role of omega-3 fatty acids in periodontal treatment

Effects of combined systemic administration of low-dose doxycycline and alendronate on endotoxin-induced periodontitis in rats

PubMed ID: 15633329Background: Doxycycline has been widely used in periodontal treatment for its antimicrobial and anti-enzymatic effects. Recently, bisphosphonates have been shown to inhibit alveolar bone resorption. The aim of the present study was to evaluate the effects of doxycycline and the bisphosphonate alendronate on the gingival tissue levels of prostaglandin E2 (PGE2), prostaglandin F2? (PGF2?), leukotriene B4 (LTB4), and platelet-activating factor (PAF) in endotoxin-induced periodontal breakdown in rats. Methods: Experimental periodontitis was induced by repeated injection of Escherichia coli endotoxin (LPS) and 44 adult male Sprague-Dawley rats were divided into five study groups as follows: LPS, doxycycline + LPS, alendronate + LPS, doxycycline + alendronate + LPS, and saline control. Doxycycline and alendronate were given either as a single agent or as a combination therapy during the 7-day study period. At the end of the 1-week protocol, the rats were sacrificed, the gingival tissues were dissected and extracted, and the extracts were analyzed for PGE2, PGF2?, LTB4, and PAF levels. The defleshed jaws were analyzed morphometrically for alveolar bone loss. Data were evaluated statistically by using parametric tests. Results: Alveolar bone loss measurements revealed significantly higher values in LPS, doxycycline + LPS, alendronate + LPS, and doxycycline + alendronate + LPS groups in comparison to the saline control group (P <0.05). Combined administration of doxycycline and alendronate exhibited the most prominent inhibition on gingival tissue levels of PGE2 and PGF2?, (P<0.05). Doxycycline + alendronate + LPS group also significantly reduced LTB4 and PAF levels, although doxycycline provided the most reduction in the levels of these mediators (P <0.05). Conclusions: Alendronate and/or doxycycline may provide significant inhibition of the major inflammatory mediators of periodontal tissue destruction, and combined administration of these agents may provide beneficial effects in periodontal treatment. However, this hypothesis must be further verified by clinical human trials before introducing its use in dental practice