Effect of probiotic therapy on periodontal tissues and intestinal mucosa of rats with ligature-induced periodontitis

Introduction: As periodontitis is caused by dysbiotic biofilm, it is believed that therapy with probiotics can act to control the mechanisms of adhesion and colonization, competing with invading microorganisms. Objective: Evaluate probiotic therapy effect on periodontal tissues and intestinal mucosa of rats with ligature-induced periodontitis. Methods: 32 Wistar rats were divided into four groups (n=8): Control Group (CG); Periodontal disease (PD); Probiotic (PROB); PD + probiotic (PDPRO). PD and PDPRO received a ligature over the first lower molars and PROB and PDPRO the probiotic Lactobacillus acidophilus based were given orally for 44 days. The animals were euthanized and the blood was collected for evaluation of triglyceride and cholesterol concentrations. The hemimandibles were collected for histomorphometric and radiographic analysis. The duodenum was removed for morphological evaluation and gingival tissue around the molars was collected for analysis of IL-17. Results: The ANOVA one-way test was used followed by Tukey Test. PDPRO had a significantly lower bone loss than the PD (p<0.05) and a smaller number of osteoclasts on PDPRO when compared to the PD. As for IL-17, there was a decrease in the PDPRO when compared to the PD. The histomorphometry of the duodenum showed that there was a significant increase in the width of the villi in PROB only. Conclusion: The therapy with probiotics was effective to avoid the development of periodontitis by reducing alveolar bone loss and inflammation modulation and increasing the width of the duodenum villi, which may help to restabilize the balance of the gastrointestinal tract.

Maternal periodontal disease as a risk factor for preterm birth and low-birth-weight babies: a case-control study

Periodontal disease is considered a public health problem because of its high prevalence, while premature birth is a serious perinatal problem, persisting as one of the major causes of perinatal mortality and morbidity. Therefore, the objective of this study was to evaluate the effect of maternal periodontal disease on the occurrence of preterm birth and the birth weight of their babies. The study sample included 45 new mothers, aged 18-35 years, who presented either slight or moderate to severe localized or generalized chronic periodontitis with bleeding on probing and gingival inflammation. The women were divided into 2 groups: slight periodontal disease (SPD; n = 15) and moderate to severe periodontal disease (MSPD; n = 30). The women underwent periodontal evaluations 48 hours after delivery of their newborns. The evaluations consisted of the following parameters: Plaque Control Record, Gingival Index, probing depth, clinical attachment level, and gingival crevicular fluid analysis. In addition, pregnancy data and neonate data, such as birth weight and gestational age at birth, were collected. In the MSPD group, there were moderate, statistically significant negative correlations between the amount of maternal gingival crevicular fluid and the newborn's gestational age at birth (-0.5388; P = 0.0014); maternal Plaque Control Record and gestational age (-0.5026; P = 0.0046); and maternal Gingival Index and gestational age (-0.4562; P = 0.0112). In the SPD group, there were no statistically significant correlations between the maternal periodontal parameters and the newborn's gestational age or birth weight. The data in the present study suggest that the presence of inflammation caused by moderate to severe periodontitis may represent a risk factor for the occurrence of preterm birth.

Low-Level Laser Effect on Peripheral Sciatic Regeneration Under the Systemic Inflammatory Condition of Periodontal Disease

Introduction: Periodontal disease (PD) is an inflammatory condition, which leads to tooth loss and promotes a systemic inflammatory state that can aggravate the nerve degeneration. As laser therapy may stimulate regeneration, this study aimed to evaluate the effect of the low-level laser (LLL) on peripheral nerve regeneration under the systemic inflammatory condition of PD. Methods: Thirry-two male rats were used, distributed in 4 groups: nerve injury (NIG); periodontal disease with nerve injury (PDNI); nerve injury and treatment (TNIG); periodontal disease with nerve injury and treatment (PDNIT). On the 7th day of the experiment, the animals had ligatures placed around the lower first molars. On the 22nd day, they underwent peripheral nerve damage, and on the 25th day, the LLL treatment was initiated, performed for two weeks. The sciatic functional index (SFI) was evaluated with subsequent euthanasia of all the animals on the 37th day of the experiment. The sciatic nerve was collected for morphological and oxidative stress analysis and the hemi jaws for radiographic analysis. Results: Regarding the SFI, there was no difference among the groups in the first evaluation (EV) pre-injury; as for theEV2, after injury, all the groups presented a decrease in these values, which remained in post-treatment. For the morphology of the PDNI, nerve tissue presented larger diameter fibers, whereas, for NIT and PDNIT, fibers had smaller diameters with endoneurial organization. When it comes to the antioxidant system, there was an increase in protein concentration, higher superoxide activity, and decreased glutathione transferase activity in the treated groups. Catalase and cholinesterase did not differ between the groups, and lipoperoxidation (LPO) increased in the PD groups. For the mandible radiographic analysis, it was possible to verify the induction of PD. Conclusion: As for the used parameters, the low-level laser was not effective in increasing the nociceptive threshold, but it contributed to the regeneration of nerve fibers, although the inflammation was still present in the site. However, the treatment was effective in protecting cells against oxidative damage due to increased SOD and increased protein, although the decrease in GST demonstrates the inhibition of this stage of the antioxidant system.

Clinical Evaluation of Obesity In Patients with Type 2 Diabetes Mellitus after Periodontal Treatment: A Comparative Study

AIM

Periodontitis is often associated with diabetes mellitus and may be considered one of the chronic complications of this disease. Increasing evidence indicates that periodontal disease (gingivitis and periodontitis) has an adverse effect on glycemic control and participates in the pathophysiology of complications related to type 2 diabetes mellitus. Thus, this study aimed to evaluate the influence of obesity on clinical periodontal parameters of patients with type 2 diabetes mellitus with stage II or III periodontitis grade C after conventional periodontal treatment.

METHODS

For this study, 36 patients, aged 25 to 65 years, were evaluated; 20 patients with type 2 diabetes mellitus and moderate to severe periodontitis (Non-Obese Group) and 16 patients with type 2 diabetes mellitus with obesity and moderate to severe periodontitis (Obese Group). These patients underwent conventional periodontal treatment and were evaluated using plaque index, probing depth, clinical attachment level, bleeding on probing and gingival crevicular fluid analysis, as well as laboratory tests of glycated hemoglobin, fasting glycemia, total cholesterol, and fractions of triglycerides. Periodontal and laboratory parameters were evaluated at baselineand six months.

RESULTS

The results showed improvements in periodontal and clinical laboratory parameters(p less than 0.05) in the evaluated periods; however, the non-obese group presented significantly better results when compared to the obese group.

CONCLUSION

It can be concluded that the presence of obesity may hinder the improvement of periodontal clinical parameters after conventional periodontal treatment in patients with diabetes mellitus and periodontitis.

BONE TISSUE BEHAVIOR OF RATS WITH EXPERIMENTAL PERIODONTITIS SUBJECTED TO PHYSICAL EXERCISE

ABSTRACT Introduction: It is possible that physical activity protects the periodontium by mitigating excessive inflammatory response of the individual. There is some evidence from longitudinal studies and a prospective study demonstrating that physically active adults have experienced a decrease in the risk of periodontitis. To date no study has jointly explored the relationship of physical activity and periodontitis using inflammatory biomarkers. Objective: In this regard, the objective was to assess the bone tissue behavior of rats with experimental periodontitis subjected to aquatic exercise. Methods: Twenty-four male Wistar rats were divided into four groups: 1) without periodontitis and without exercise (CS); 2) without periodontitis and with exercise (CE); 3) with periodontitis and without exercise (DPS); 4) with periodontitis and with exercise (DPE). The animals from groups CE and DPE had swimming sessions for four weeks and the DPS and DPE groups were subjected to ligature-induced periodontitis. After 30 days the animals were sacrificed, and had their right and left hemimandibles removed for radiographic and histological analysis. The data obtained were analyzed and evaluated through ANOVA and Tukey tests. Results: Bone loss in the animals from the DPE group was found to be significantly lower (61.7 ± 2.2; p <0.05) than in those from the DPS group (84.5 ± 1.2; p <0.05), while in terms of the number of osteoblasts (DPS=11.0 ± 1.4; DPE=10.7 ± 5.2) and osteocytes (DPS=17.3 ± 3.1; DPE=19.0 ± 4.4), there was no significant decrease (p <0.05) in the groups subjected to experimental periodontitis, regardless of physical exercise. Conclusion: Physical exercise was found to have a protective effect in relation to bone height and did not influence bone density. Level of evidence II; Therapeutic studies - investigation of treatment results.

Comparative Clinical Evaluation between Conventional Periodontal Treatment and Full Mouth Disinfection

Periodontal disease is chronic and multifactorial, affecting protection and support tissues of the tooth. Its onset is due to the accumulation of bacterial plaque, in which are found microorganisms, mainly Gram-negative, which stimulate the host cells and the production of immune-inflammatory molecules. Thus, the objective of this research was to evaluate the effectiveness of two techniques of periodontal treatment through clinical parameters and laboratory tests. For this, 42 patients were randomly evaluated and divided into three groups of 14 patients each: Group 1 (control) - periodontally healthy patients; Group 2 - patients with moderate to severe chronic periodontitis treated with conventional periodontal treatment [quadrant scaling and root planing (Q-SRP)]; and Group 3 - patients with moderate to severe chronic periodontitis treated with full-mouth scaling and root planing (FM-SRP). All of these patients received periodontal treatment and were evaluated using the plaque and gingival indices, probing depth (PD), clinical attachment level (CAL), bleeding on probing (BOP), analysis of prostaglandin E2 (PGE2) isoform expression and analysis of gingival crevicular fluid (GCF), for a total period of 180 days. The results of the periodontal and laboratory parameters did not show significant differences statistically (p > 0.05) when comparing the treatments at 180 days. Therefore, it can be affirmed that both periodontal treatments were effective, but without differences between them. Both treatments improved periodontal and laboratorial clinical parameters significantly. Thus, the professional should evaluate the case and choose the treatment that best suits the needs of the patient and availability.

Comparing semilunar coronally positioned flap to standard coronally positioned flap using periodontal clinical parameters

This study compared the effectiveness of 2 surgical root coverage techniques--semilunar coronally positioned flap and coronally advanced flap--using the clinical parameters of periodontal tissues from patients with Miller Class I gingival recession. Twenty patients (20-50 years of age) were selected. Basic periodontal treatment was performed, and plaque index, gingival index, probing depth, clinical attachment level, and height of the attached gingiva were determined. Each patient was placed into 1 of 2 groups: Group 1 patients underwent the semilunar coronally positioned flap technique, and Group 2 patients underwent the coronally advanced flap technique. Patients were assessed for 180 days. Both groups showed significant reduction of plaque and gingival indices and an improvement in clinical attachment levels and probing depth. However, results showed the standard coronally positioned flap technique was deemed more effective due to significant clinical attachment level gains.

Evaluation of the effect of simvastatin on the progression of alveolar bone loss in experimental periodontitis--an animal study

AIM

The aim of the present study was to evaluate the effect of simvastatin, a potent antiinflammatory drug, on the progression of alveolar bone loss in an experimental model of periodontitis in rats.

MATERIAL AND METHODS

A cotton ligature was used around the lower right first molar in a submarginal position in order to induce experimental periodontitis. Sixty rats were divided into 12 groups consisting of three control groups, three simvastatin groups, three ligature groups, and three ligature plus simvastatin groups. The distance between the cemento-enamel junction and the alveolar crest was determined at the mesial root surfaces of the lower right first molars by radiographic as well as profilometric analyses.

RESULTS

In rats of the experimental periodontitis group (ligature), alveolar bone loss was higher compared to the control groups. However, simvastatin was associated with decreased alveolar bone loss in all treatment groups with experimental periodontitis (p < 0.01).

CONCLUSION

Simvastatin treatment seems to be a beneficial and supporting therapeutic that favors protection against alveolar bone loss in a model of experimental periodontitis in rats.

Lipid profiles and inflammatory markers after periodontal treatment in children with congenital heart disease and at risk for atherosclerosis

Due to the biological associations between periodontal and cardiovascular diseases, as well as the fact that atherosclerosis begins in childhood, behavior based on oral health care and metabolic control from an early age is essential for patients with cardiovascular disease. The aim of this research was to examine the effect of full-mouth scaling and root planing on the reduction of periodontal disease in children with congenital heart disease. In this study, treatments were related to clinical periodontal parameters and also to blood ones, such as lipid profile and inflammatory markers. The patients were divided into two groups: group 1 (n=17), scaling and root planing; and group 2 (n=16), full-mouth scaling and root planing. The results showed a significant improvement in clinical periodontal parameters (P<0.05) in both groups. Considering lipid parameters, total cholesterol, triglycerides, and very-low-density lipoprotein parameters showed significant improvement (P<0.05). There was also an improvement in C-reactive protein (ultrasensitive) in the group treated with scaling and root planing (P<0.05). Fibrinogen and interleukin-6 parameters improved (P<0.05) in both groups. We suggest that both periodontal treatments were effective in children with congenital heart disease, though neither demonstrated superiority.

Radiographic evaluation of the effect of obesity on alveolar bone in rats with ligature-induced periodontal disease

There is evidence that the lack of metabolic control of obese patients may accelerate periodontitis. The aim of this study was to evaluate radiographically the effect of cafeteria-diet-induced obesity on alveolar bone loss in rats subjected to periodontal disease. Twenty male Wistar rats were randomly divided into four groups: 1) control group, 2) control and ligature group; 3) cafeteria group; and 4) cafeteria and ligature group. The animals were evaluated for obesity and euthanized, and the mandible of each rat was removed to perform a radiographic evaluation of alveolar bone loss and its effect on diet-induced obesity. The results showed greater alveolar bone loss in the mice in Group 4 (P<0.01). Thus, we concluded that obese mice, on average, showed greater radiographic evidence of alveolar bone loss than mice undergoing induction of obesity.

Periodontal evaluation of different toothbrushing techniques in patients with fixed orthodontic appliances

INTRODUCTION: Plaque control is the major consensus during orthodontic treatment to prevent the occurrence of cavities and periodontal inflammation. The mechanic resource of greater effectiveness and frequent use in this control is the oral hygiene. The tooth brushing techniques most used in orthodontic patients are: Ramfjord's method, Modified Stillman technique and Bass method. OBJECTIVE: Since control studies evaluating the effectiveness of usual tooth brushing techniques do not show clear advantage, the objective of this study was to evaluate the effectiveness of three brushing methods, through periodontal clinical parameters of patients with fixed orthodontic appliances. METHODS: Thirty patients were selected, with ages between 14 and 22 years old, with fixed orthodontic appliances. After basic periodontal treatment the following factors were evaluated: 1 - Plaque index and 2 - Gingival index and each patient was randomly included in one of the three selected groups according to the brushing technique: Group 1 - Scrubbing technique; Group 2 - Modified Stillman technique and Group 3 - Bass technique. Patients were evaluated for 9 months. RESULTS: The results showed a significant reduction of clinical parameters by the end of this period, however there was a very significant reduction of Gingival index on group 3 (13.6%) when compared to the other groups. CONCLUSION: Thus, it can be suggested that the Bass technique can be effective on the reduction of periodontal clinical parameters of Plaque index and Gingival index in patients with fixed orthodontic appliances.

Lipid profile of people with diabetes mellitus type 2 and periodontal disease

The objective of this study was to evaluate improvement of lipids and periodontal disease in patients with type 2 Diabetes mellitus, by means of the relationship between blood levels of total cholesterol and its fractions, triglycerides and clinical periodontal parameters. Twenty patients, in age-range 18-70 years, were selected and divided into 2 groups: (1) conventional periodontal scaling and root planing+controlled mechanic; (2) conventional periodontal scaling and root planing+controlled mechanical+maintenance therapy. The analyses were performed on day 0, 180 and 720 days, including plaque index, gingival index, probing depth and clinical attachment level, and evaluation of total cholesterol and its fractions, and triglycerides. The 2 groups presented significant reduction in clinical periodontal parameters, however, probing depth did not diminish significantly only in Group 1. There was significant improvement in all blood parameters in both groups. It was concluded that after 720 days of the experiment, there were significant improvements in clinical and blood parameters, in general. The group that received maintenance therapy also showed a more expressive improvement in clinical periodontal parameters, in general, suggesting that this therapy is important and necessary in patients with type 2 Diabetes mellitus and periodontal disease.

Effect of maintenance therapy with or without the use of chlorhexidine in teeth restored with composite resin in patients with diabetes mellitus

The objective of this study was to evaluate the effects of maintenance therapy with or without the use of 0.12% chlorhexidine in the periodontal tissues of patients with diabetes mellitus who had carious lesions restored with composed resin. Twenty patients were selected, all of whom had diabetes mellitus in addition to carious cervical lesions in previously treated teeth. After 90 days, improvement in plaque and gingival indices and probing depth were noticed among patients in the group that received 0.12% chlorhexidine.

Simvastatin therapy in cyclosporine A-induced alveolar bone loss in rats

BACKGROUND AND OBJECTIVE

Cyclosporine A treatment is important in the therapy of a number of medical conditions; however, alveolar bone loss is an important negative side-effect of this drug. As such, we evaluated whether concomitant administration of simvastatin would minimize cyclosporine A-associated alveolar bone loss in rats subjected, or not, to experimental periodontal disease.

MATERIAL AND METHODS

Groups of 10 rats each were treated with cyclosporine A (10 mg/kg/day), simvastatin (20 mg/kg/day), cyclosporine A and simvastatin concurrently (cyclosporine A/simvastatin) or vehicle for 30 days. Four other groups of 10 rats each received a cotton ligature around the lower first molar and were treated similarly with cyclosporine A, simvastatin, cyclosporine A/simvastatin or vehicle. Calcium (Ca(2+)), phosphorus and alkaline phosphatase levels were evaluated in serum. Expression levels of interleukin-1beta, prostaglandin E(2) and inducible nitric oxide synthase were evaluated in the gingivomucosal tissues. Bone volume and numbers of osteoblasts and osteoclasts were also analyzed.

RESULTS

Treatment with cyclosporine A in rats, with or without ligature, was associated with bone loss, represented by a lower bone volume and an increase in the number of osteoclasts. Treatment with cyclosporine A was associated with bone resorption, whereas simvastatin treatment improved cyclosporine A-associated alveolar bone loss in all parameters studied. In addition, simvastatin, in the presence of inflammation, can act as an anti-inflammatory agent.

CONCLUSION

This study shows that simvastatin therapy leads to a reversal of the cyclosporine A-induced bone loss, which may be mediated by downregulation of interleukin-1beta and prostaglandin E(2) production.

Treatment with tacrolimus enhances alveolar bone formation and decreases osteoclast number in the maxillae: a histomorphometric and ultrastructural study in rats

Recent studies have suggested that tacrolimus monotherapy is a beneficial therapeutic alternative for the normalization of cyclosporin-induced bone loss in animal models and humans. The mechanism accounting for this action is unclear at present. In the present study, we attempted to determine the effect of tacrolimus monotherapy on alveolar bone using histological, histomorphometric and transmission electron microscopy (TEM). Groups of rats (n=10 each) were treated with either tacrolimus (1mg/kg/day, s.c.) or drug vehicle for 60 days. Fragments containing maxillary molars were processed for light microscopy to investigate the alveolar bone volume, trabecular separation, number of osteoclasts and osteoblasts, and transmission electron microscopy to investigate their ultrastructural basic phenotype. Treatment with tacrolimus monotherapy during 60 days may induce increases in alveolar bone volume (BV/TV,%; P<0.05) and a non-significant decrease in trabecular separation (Tb.Sp,mm; P>0.05), represented by a decrease in osteoclast number (N.Oc/BS; P<0.05) and maintenance of osteoblast number (N.Ob/BS; P>0.05). Osteoblasts were often observed as a continuous layer of active cells on the bone surface. Osteoclasts appeared to be detached from the resorbed bone surface, which was often filled by active osteoblasts and collagen-rich matrix. Moreover, osteoclasts in the treated group were frequently observed as inactive cells (without ruffled border, clear zone and detached from the bone surface). Within the limits of the present study, we conclude that tacrolimus leads to an increase in alveolar bone formation, which probably exerts action on osteoclasts. Tacrolimus could, therefore, play a crucial role in the control of both early osteoclast differentiations from precursors, as well as in functional activation.

Biochemical evaluation of glycemic levels of long-term tacrolimus therapy in rats

One of the more serious complications following transplantation is the development of post-transplantation diabetes mellitus (PTDM), which has a major impact on the quality of life, with effects ranging from the control of glycemia times to increased susceptibility to infections and cardiovascular complications. It has been suggested that immunosuppressive therapy, mainly tacrolimus therapy, may be an important factor in the development of PTDM. There is a lack of studies that explore the effects of long-term tacrolimus on PTDM in animal protocols. The objective of this study was therefore to evaluate the effects of long-term therapy with tacrolimus in rats. One group was treated with tacrolimus, injected subcutaneously, in a daily dose of 1 mg/kg of body weight. The chosen dose was sufficient to achieve therapeutic tacrolimus serum levels. The experimental periods were 60, 120, 180 and 240 days. One group was used as control and received daily subcutaneous injections of saline solution during all periods. A tendency towards increased glycemia levels during the initial periods (60 and 120 days) was observed. However, at 180 and 240 days, the glycemia levels were not statistically different from that of the control group of the same period. It may thus be concluded that the deleterious effects of tacrolimus therapy on glycemia may be a time-related side effect.

Alendronate therapy in cyclosporine-induced alveolar bone loss in rats

BACKGROUND AND OBJECTIVE

Cyclosporine A is an immunosuppressive drug that is widely used in organ transplant patients as well as to treat a number of autoimmune conditions. Bone loss is reported as a significant side-effect of cyclosporine A use because this can result in serious morbidity of the patients. As we have shown that cyclosporine A-associated bone loss can also affect the alveolar bone, the purpose of this study was to evaluate the effect of the concomitant administration of alendronate on alveolar bone loss in a rat model.

MATERIAL AND METHODS

Forty Wistar rats (10 per group) were given cyclosporine A (10 mg/kg, daily), alendronate (0.3 mg/kg, weekly), or both cyclosporine A and alendronate, for 60 d. The control group received daily injections of sterile saline. The expression of proteins associated with bone turnover, including osteocalcin, alkaline phosphatase and tartrate-resistant acid phosphatase (TRAP), and also the calcium levels, were evaluated in the serum. Analysis of the bone volume, alveolar bone surface, the number of osteoblasts per bone surface and the number of osteoclasts per bone surface around the lower first molars was also performed.

RESULTS

The results indicate that cyclosporine A treatment was associated with bone resorption, represented by a decrease in the bone volume, alveolar bone surface and the number of osteoblasts per bone surface and by an increase in the number of osteoclasts per bone surface and TRAP-5b. These effects were effectively counteracted by concomitant alendronate administration.

CONCLUSION

It is concluded that concomitant administration of alendronate can prevent cyclosporine A-associated alveolar bone loss.

Cyclosporin A-induced new cementum formation: a morphometric evaluation in the periapical region of rats

Cyclosporin A (CsA) is a potent immunosuppressor used in organ transplantation and in the management of various autoimmune diseases. Recent studies have shown that CsA stimulates deposition of cementum on root surfaces. The aim of this study was to evaluate the periapical cementum thickness and the apical foramen width in CsA-treated rats. Rats weighing 50 g were treated with a daily injection of 10 mg/kg body weight of CsA in the chow for 60 days. The cementum of the mandibular 1st molars was histologically and morphometricaly examined by analysis of 5-microm-thick serial buccolingual paraffin sections stained with hematoxylin and eosin. Histometric and stereologic analyses revealed the presence of large amounts of cementum in all root surfaces, particularly abundant in the periapical region and obliterating the foramen. The volume density of cementoblasts did not increase. Five to 90 days after the termination of CsA therapy, there was no reduction of cementum thickness. These results suggest that cementum deposition is not reversible after cessation of CsA treatment.

Protective effects of Tacrolimus, a calcineurin inhibitor, in experimental periodontitis in rats

OBJECTIVE

Periodontitis is a well-appreciated example of leukocyte-mediated bone loss and inflammation with pathogenic features similar to those observed in other inflammatory diseases, such as arthritis. Since Tacrolimus, is an immunomodulatory drug used for the treatment of some cases of arthritis, we hypothesized that it may modulate periodontal disease.

DESIGN

Using a murine model of ligature-induced periodontal disease, we assessed the effects of daily administrations of Tacrolimus (1mg/kg body weight) on bone loss, enzymatic (myeloperoxidase) analysis, differential white blood cells counts, airpouch exudate and cytokine expression for 5-30 days.

RESULTS

Radiographic, enzymatic (myeloperoxidase) and histological analysis revealed that Tacrolimus reduced the severity of periodontitis. More specifically, Tacrolimus suppressed the expression of serum interleukin (IL-1beta), tumour necrosis factor (TNF-alpha), IL-6, airpouch exudate PGE(2) and leukocytosis usually observed after the induction of periodontitis. Tacrolimus treatment in periodontitis-induced rats conferred protection against the inflammation-induced tissue and bone loss associated with periodontitis, through a mechanism involving IL-1beta, TNF-alpha and IL-6.

CONCLUSIONS

The effects of Tacrolimus on periodontal disease pathogenesis may provide clues to a novel approach to host modulation therapy in destructive periodontal disease.

Effects of long-term cyclosporin therapy on gingiva of rats: analysis by stereological and biochemical estimation

Cyclosporin A (CsA) is used as an immunosuppressive agent and its prominent side effect is the induction of gingival overgrowth, which remains a significant problem. The risk factors appraised include the duration of treatment. However, there are no stereological and biochemical studies exploring the effects of long-term CsA therapy on gingival tissue. The purpose of the present study was to investigate the level of TGF-beta1 in saliva and describe the densities of fibroblasts and collagen fibers in the gingival tissue of rats treated with CsA for long periods. Rats were treated for 60, 120, 180 and 240 days with a daily subcutaneous injection of 10 mg/kg of body weight of CsA. At the end of the experimental periods, saliva was collected for the determination of TGF-beta1 levels. After histological processing, the oral epithelium and the connective tissue area were measured as well as the volume densities of fibroblasts (Vf) and collagen fibers (Vcf). After 60 and 120 days of CsA treatment, there was a significant increase in Vf and Vcf as well as a significant increase in TGF-beta1 levels. After 180 and 240 days, reduction in the gingival overgrowth associated with significant decreases in the level of TGF-beta1, and also decreased Vf and Vcf, were observed. The data presented here suggest that after long-term therapy, a decrease in TGF-beta1 levels occurs, which might contribute to an increase in the proteolytic activity of fibroblasts in the gingiva, favoring the normality of extracellular matrix synthesis.

Effect of cyclosporin A on alveolar bone homeostasis in a rat periodontitis model

OBJECTIVES

The administration of cyclosporin A has been associated with significant bone loss and increased bone remodeling. The present investigation was designed to evaluate the effects of cyclosporin A on alveolar bone of rats subjected to experimental periodontitis, using serum, stereometric and radiographic analysis.

METHODS

Twenty-four rats were divided into one of the following groups with six animals each: group I, control rats; group II, in which the animals received a cotton ligature around the lower first molars; group III, in which the rats received a cotton ligature around the lower first molars and were treated with 10 mg/(kg body weight day) of cyclosporin A; group IV, in which the rats were treated with 10 mg/(kg body weight day) of cyclosporin A. At the end of experimental period, at 30 days, animals were killed and the serum calcium and alkaline phosphatase levels were measured in all groups. The distance from the alveolar bone crest to the cemento-enamel junction was measured radiographically for each mesial surface of the lower first molars of each rat. After histological processing, the stereological parameters: volume densities of multinucleated osteoclasts (V(o)), alveolar bone (V(b)), marrow (V(m)), and relation of eroded surface/bone surface (Es/Bs) were assessed at the mesial region of the alveolar bone.

RESULTS

Significant decreases in serum calcium were observed in those groups that received cyclosporin A therapy. No significant changes in serum alkaline phosphatase were observed. The therapy with cyclosporin A combined with the ligature placement decreased the V(b) and increased the V(o), V(m) and Es/Bs at the mesial surface of lower first molars. On the other hand, the radiographic data showed that cyclosporin A therapy diminished the alveolar bone loss at the mesial surface of the lower first molars.

CONCLUSIONS

Therefore, within the limits of this study, we suggest that cyclosporin A at immunosuppressive levels can bring about an imbalance in the alveolar bone homeostasis in rats. However, in the presence of inflammatory stimulation, the inhibition of the immune system by cyclosporin A may decrease the initial periodontal breakdown.

Influence of Age on Combined Effects of Cyclosporin and Nifedipine on Rat Alveolar Bone

BACKGROUND

There is some evidence showing that cyclosporin A (CsA) and nifedipine (NIF) affect bone metabolism. The purpose of this work was to study the effects of CsA and NIF, given alone or concurrently, on alveolar bone of rats of different ages.

METHODS

Rats 15, 30, 60, and 90 days old were treated daily with 10 mg/kg body weight of CsA subcutaneously injected and/or 50 mg/kg body weight of NIF/day given orally for 60 days. Alveolar bone of the first lower molars was morphologically and stereologically evaluated in serial 5 microm bucco-lingual paraffin sections, stained with hematoxylin and eosin. Serum calcium and alkaline phosphatase levels were measured in all animals at the end of the experimental period.

RESULTS

Rats treated with CsA or NIF alone or CsA and NIF concurrently showed decreased alveolar bone density. CsA was more effective than NIF. A significant decrease in serum calcium was found only in animals treated with CsA or CsA/NIF. The results were similar regardless of age.

CONCLUSIONS

These results indicate that the decrease in the alveolar bone volume in rats caused by CsA and NIF alone or concurrently is not age dependent. Furthermore, NIF (50 mg/kg) did not further increase the loss of alveolar bone volume induced by CsA (10 mg/kg).