Inhibition of Experimental Gingivitis in Beagle Dogs With Topical Mercaptoalkylguanidines

Systemic use of selective iNOS inhibitor 1400W or non-selective NOS inhibitor l-NAME differently affects systemic nitric oxide formation after oral Porphyromonas gingivalis inoculation in mice

OBJECTIVE

Nitric oxide synthase (NOS) inhibitors are reported to protect against the local tissue damage in gingivitis and periodontal disease by reducing nitroxidative stress during inflammation, but their systemic effects are not well investigated.

DESIGN

NOS inhibitors systemic effects were investigated in a murine chronic oral inoculation model using live Porphyromonas gingivalis ATCC 33277 (0.3 ml; 10(9)cfu/ml) or sterile broth (0.3 ml). Organ nitric oxide (NO) and plasma nitrite/nitrate (NOx) were determined in mice treated with non-selective NOS inhibitor l-NAME (50mg/kg/24h i.p.) or selective iNOS inhibitor 1400W (10mg/kg/6h i.p.) for the last 5 days of the experiment. Differences between groups were evaluated by nonparametric Wilcoxon's rank-sum one-sided two-sample test and the results compared to those obtained from sham-treated (sterile broth) sham-inoculated animals (water for injection i.p./6h).

RESULTS

Repeated ingestion of P. gingivalis resulted in generalized production of NO in organs and NOx in plasma, the levels of both typically being reduced in P. gingivalis-inoculated-1400W-treated mice, whilst the use of l-NAME was largerly ineffective, even promoting NO/NOx formation. Application of either inhibitor to sham-inoculated animals enhanced NO/NOx formation, due only in part to the repeated i.p. injections.

CONCLUSIONS

The systemic use of 1400W or l-NAME differently affects systemic nitric oxide formation in mice orally challenged with P. gingivalis, but the sequelae of such an intervention should be evaluated further.

In vitro and in vivo suppression of cellular activity by guanidinoethyl disulfide released from hydrogel microspheres composed of partially oxidized hyaluronan and gelatin

This paper describes the preparation of oxidized hyaluronan crosslinked gelatin microspheres for drug delivery. Microspheres were prepared by a modified water-in-oil-emulsion crosslinking method, where three-dimensional crosslinked hydrogel microspheres formed in the absence of any extraneous crosslinker. SEM analyses of the microspheres showed rough surfaces in their dried state with an average diameter of 90 microm. Lyophilization of fully swollen microspheres revealed a highly porous structure. Guanidinoethyl disulfide (GED) was used as a model drug for incorporation into the microspheres; encapsulation of GED was confirmed by HPLC. There was an inverse correlation between the diameters of the microspheres with their GED loading. Macrophage was used as a model cell to evaluate the in vitro efficacy of GED release from the microspheres. The in vivo efficacy of the microspheres was further validated in a mouse full-thickness transcutaneous dermal wound model through suppression of cell infiltration.

Free radicals and antioxidants in inflammatory processes and ischemia-reperfusion injury

This article discusses the current understanding of the role of free radicals and antioxidants in inflammatory processes and in ischemia reperfusion injury. It begins by describing the manifestations of acute inflammation and outlining the cellular events that occur during inflammation. It then describes the biochemical mediators of inflammation with special attention to nitric oxide. It details the process of hypoxia reperfusion injury, the enzymes involved, its treatment, and studies involving specific hypoxia reperfusion injuries in various animal species.