Nifedipine-induced gingival overgrowth in the presence or absence of gingival inflammation in rats

Nifedipine Exacerbates Lipogenesis in the Kidney via KIM-1, CD36, and SREBP Upregulation: Implications from an Animal Model for Human Study

Dysregulation of fatty acid oxidation and accumulation of fatty acids can cause kidney injury. Nifedipine modulates lipogenesis-related transcriptional factor SREBP-1/2 in proximal tubular cells by inhibiting the Adenosine 5‘-monophosphate (AMP)-activated protein kinase (AMPK) pathway in vitro. However, the mechanisms by which nifedipine (NF) modulates lipotoxicity in vivo are unclear. Here, we examined the effect of NF in a doxorubicin (DR)-induced kidney injury rat model. Twenty-four Sprague–Dawley rats were divided into control, DR, DR+NF, and high-fat diet (HFD) groups. The DR, DR+NF, and HFD groups showed hypertension and proteinuria. Western blotting and immunohistochemical analysis showed that NF significantly induced TNF-α, CD36, SREBP-1/2, and acetyl-CoA carboxylase expression and renal fibrosis, and reduced fatty acid synthase and AMPK compared to other groups (p < 0.05). Additionally, 18 patients with chronic kidney disease (CKD) who received renal transplants were enrolled to examine their graft fibrosis and lipid contents via transient elastography. Low-density lipoprotein levels in patients with CKD strongly correlated with lipid contents and fibrosis in grafted kidneys (p < 0.05). Thus, NF may initiate lipogenesis through the SREBP-1/2/AMPK pathway and lipid uptake by CD36 upregulation and aggravate renal fibrosis in vivo. Higher low-density lipoprotein levels may correlate with renal fibrosis and lipid accumulation in grafted kidneys of patients with CKD.

Amlodipine-Induced Gingival Overgrowth in a Patient With Uncontrolled Type 2 Diabetes Mellitus With Hypercholesterolemia: A Case Report

INTRODUCTION

Gingival overgrowth, with its potential cosmetic implications and for providing new niches for the growth of microorganisms, is a serious concern for both patients and clinicians. Amlodipine is a comparatively new calcium channel blocker and is being used with increasing frequency in the management of hypertension and angina. Although amlodipine is considered a safe drug, it may induce gingival overgrowth in some individuals.

CASE PRESENTATION

A rare case of amlodipine-induced gingival overgrowth in a 60-year-old Indian woman who was on amlodipine for 3 years and subsequent periodontal management of the overgrowth is reported here. The patient did not have any gingival overgrowth for 2 years despite the fact that she was taking amlodipine, but she developed the gingival overgrowth 9 months before her initial visit, coincident with uncontrolled diabetes mellitus and use of a cholesterol-lowering drug. She was treated with drug substitution for the systemic condition and surgical treatment for the overgrowth. She was followed up for 1 year, regularly.

CONCLUSION

We speculate that overgrowth could have been triggered by uncontrolled type 2 diabetes mellitus and by altered pharmacokinetics of amlodipine resulting from the drug interaction of amlodipine with a cholesterol-lowering drug.

Differences of Cell Growth and Cell Cycle Regulators Induced by Basic Fibroblast Growth Factor Between Nifedipine Responders and Non-responders

Differences of cell proliferation, cell cycle, and G(1)/S transition regulatory proteins of gingival fibroblasts derived from nifedipine-reactive patient (NIFr) and nifedipine-non-reactive patient (NIFn) in the presence of basic fibroblast growth factor (bFGF) were investigated to elucidate the mechanism of gingival overgrowth associated with nifedipine, one of the Ca(2+)-channel blockers. The proliferation rate of NIFr cells in the presence of bFGF significantly increased than NIFn cells. The proportion of NIFr cells that had undergone progression to the S and G(2)/M phases from the G(0)/G(1) phase significantly increased compared to that in NIFn cells. Increases of pRB (Ser807/811), pCDK2 (Thr160), CDK2, and cyclin E protein levels in NIFr cells were greater than those in NIFn cells. The elevations of pRB (Ser780), RB, and cyclin A protein levels in NIFr cells did not differ from those of NIFn cells. The growth of NIFr cells was greater than that of NIFn cells as a result of the active G(1)/S transition of NIFr cells, as assessed by the increments of cyclin E, pCDK2, and pRB (ser807/811) protein in NIFr cells.

Diltiazem did not induce gingival overgrowth in rats: a clinical, histological and histometric analysis

The administration of calcium channel blockers has been associated with gingival overgrowth. However, there are few studies in humans or animals that evaluated the effect of diltiazem on gingival tissues. The present study assessed the influence of diltiazem, at different dosages and treatment duration, on gingival tissues of rats, using clinical, histological and histometric analyses. Eighty young male rats were separated into eight groups according to the dosage and duration of treatment. Rats were treated for 20 or 40 days with a daily subcutaneous injection of 5, 20 or 50 mg/kg of body weight of diltiazem. The results confirmed that diltiazem did not induce gingival overgrowth in rats. For all animals, the evaluation did not show gingival alterations regardless of the dosages and periods of treatment. The histometric analysis showed no significant change in the area of epithelium and connective tissues, although after 40 days of treatment a decrease in the area of connective tissue was observed, without statistically significant difference from control groups. Within the limits of this study, we suggest that diltiazem did not induce gingival overgrowth.

Gingival overgrowth in children: epidemiology, pathogenesis, and complications. A literature review

Gingival overgrowth is the enlargement of the attached gingiva due to an increased number of cells. The most prevalent types of gingival overgrowth in children are drug-induced gingival overgrowth, hereditary gingival fibromatosis (HGF), and neurofibromatosis I (von Recklinghausen disease). Gingival overgrowth induced by drugs such as phenytoin, nifedipine, and cyclosporin develops due to an increase in the connective tissue extracellular matrix. According to epidemiologic studies, it is more prevalent in male children and adolescents. There is an additive effect of those drugs on the degree of gingival overgrowth. Genetic heterogeneity seems to play an important role in the development of the disease. Functional difficulties, disfigurement, increased caries, and delayed eruption of permanent teeth are the main complications of drug-induced gingival overgrowth. HGF is the most common syndromic gingival enlargement in children. This autosomal dominant disease usually appears at the time of eruption of permanent dentition. Histologically, it is characterized by highly collagenized connective tissue. The most important complications are drifting of teeth, prolonged retention of primary dentition, diastemata, and poor plaque control. Neurofibromatosis I is an autosomal dominant disease more common in mentally handicapped individuals. Gingival overgrowth is caused by the formation of plexiform neurofibromas in the connective tissue of the gingiva. Plexiform neurofibromas are pathognomonic of the disease and consist of hypertrophic nerves arranged as lobules in the connective tissue. Complications of the disease are multiple and severe due to neurofibromas and their occasional malignant transformation.

Oral and dental aspects of chronic renal failure

The present article reviews, in detail, the current knowledge of the oral and dental aspects of chronic renal failure (CRF). Worldwide, increasing numbers of persons have CRF; thus, oral health care staffs are increasingly likely to provide care for patients with such disease. Chronic renal failure can give rise to a wide spectrum of oral manifestations, affecting the hard or soft tissues of the mouth. The majority of affected individuals have disease that does not complicate oral health care; nevertheless, the dental management of such individuals does require that the clinician understand the multiple systems that can be affected. The clinician should also consider the adverse side-effects of drug therapy and appropriate prescribing, in view of compromised renal clearance.

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).

Combined effects of cyclosporin and nifedipine on gingival overgrowth in rats is not age dependent

BACKGROUND

Cyclosporin A and nifedipine cause gingival overgrowth in rat, and the combined use of these drugs increases the overgrowth severity.

OBJECTIVE

The purpose of this study was to compare gingival overgrowth of rats of differents ages treated with cyclosporin A and nifedipine alone or given concurrently.

MATERIALS AND METHODS

Rats 15, 30, 60 and 90 d old were treated with 10 mg/kg body weight of cyclosporin A and/or 50 mg/kg body weight of nifedipine in the chow.

RESULTS

Young rats showed evident gingival overgrowth with nifedipine, cyclosporin A, and cyclosporin A and nifedipine given concurrently. Adult rats did not show significant gingival alterations when treated with cyclosporin A and nifedipine alone. Nevertheless evident gingival overgrowth with alterations of the epithelium and connective tissue were observed when treated simultaneously with cyclosporin A and nifedipine.

CONCLUSION

These results suggest that the combined effects of cyclosporin A and nifedipine on gingival overgrowth in rat is not age dependent.

Synergistic enhancement of collagenous protein synthesis by human gingival fibroblasts exposed to nifedipine and TNF-alpha in vitro

BACKGROUND

Gingival overgrowth occurs in patients receiving nifedipine. Gingival inflammation may be an etiologic factor.

METHODS

Gingival fibroblasts were either exposed to (i) 0-500 ng/ml TNF-alpha or 10(-7) M nifedipine or (ii) 0-500 ng/ml TNF-alpha + 10(-7) M nifedipine for 7 days. 3H-proline was used to quantify collagenous protein synthesis.

RESULTS

Both TNF-alpha and 10(-7) M nifedipine significantly decreased cell proliferation, and 10(-7) M nifedipine + 500 ng/ml TNF-alpha reversed these effects. Collagenous protein synthesis was significantly reduced by TNF-alpha and was significantly enhanced by either 10(-7) M nifedipine or 5-500 ng/ml TNF-alpha + 10(-7) M nifedipine.

CONCLUSIONS

Our data report that nifedipine reverses the primary effects of TNF-alpha on collagenous protein synthesis. Patients with gingivitis could be susceptible to gingival overgrowth during nifedipine therapy as a result of synergistic effects of these agents on fibroblast metabolism, which occurs irrespective of reduced cell numbers.

An involvement of granulocyte medullasin in phenytoin-induced gingival overgrowth in rats

To investigate the relationship between histological changes and distributions of medullasin, a neutrophil elastase-like serine proteinase, in phenytoin-induced gingival overgrowth, we established a rat model of gingival overgrowth. Thirty-two, 20-day-old male Fischer 344 rats were fed a diet containing phenytoin and sacrificed at 1, 2, 4 and 8 weeks. Control rats (n = 40) were fed the same diet, but without the drug and killed at the same weeks as experimental rats (n = 32) and 0 week (n = 8). The mandible specimens were resected and sectioned bucco-lingually between the first and second molars. A marked inflammatory-cell infiltration and elongated rete pegs were seen in the phenytoin-treated group. The extent of the overgrowth assessed by computer image analysis and the density of medullasin-positive cells by immunohistochemistry in the approximal gingiva showed a significant increase in the phenytoin-treated group compared to the control group. A marked infiltration of the positive cells in experimental rats was observed as early as 2 weeks when gingival overgrowth was not fully established. Medullasin-positive cells were mostly neutrophils and partly macrophage-like cells. These findings suggest that medullasin may be involved in mainly host defense and secondarily collagen metabolism in the phenytoin-induced rat model of gingival overgrowth.

The gingival inflammatory infiltrate in cardiac patients treated with calcium antagonists

OBJECTIVES

To analyse the periodontal inflammatory infiltrates in patients with cardiac disease, some of these patients were treated with calcium antagonists (nifedipine and diltiazem) and some were not, to compare them with a healthy control group, and to evaluate the changes in the inflammatory infiltrate after periodontal treatment.

MATERIAL AND METHODS

A "healthy group" (HG, n=12), a "cardiac group" (CG, n=12) without treatment with calcium antagonists, a "nifedipine group" (NG, n=18) and a "diltiazem group" (DG, n=13) were analysed. Biopsies were taken from a zone 2-3 mm below the upper part of the interproximal papillae 12-13 and 33-32 before causal periodontal treatment and after 1 year. Using haematoxylin-eosin staining, the plasma cells (P), lymphocytes (L), histiocytes (H) and polymorphonuclear cells (PMN) were counted. T and B lymphocytes were evaluated using the monoclonal antibodies anti-CD20 and anti-CD45RO. Statistical tests used: chi2 for study of the sample composition; ANOVA for comparison between groups; Student t-test and Wilcoxon test for comparison between visits; post-hoc test Bonferroni.

RESULTS

When the cells were compared statistically, differences were established for L at the first visit (p<0.00001) and at the last visit (p<0.02), for the B lymphocytes (first visit p<0.0021, last visit p<0.022) and for the T lymphocytes (first visit p<0.0042, last visit p<0.0021). Between the 2 visits, HG showed significant reductions for P (p<0.01), L (p<0.045) and H (p<0.033); and the NG for L (p<0.0001). Lymphocytes showed differences in the NG with respect to the B lymphocytes (p<0.008).

CONCLUSIONS

Nifedipine affects the inflammatory infiltrate with a greater number of lymphocytes (especially B) and these cells fell significantly in number after periodontal treatment.

Amlodipine-induced gingival overgrowth: periodontal responses to stopping and restarting the drug

A case history of a woman with gingival overgrowth (GO) induced by amlodipine is presented. A 49-year-old Japanese woman, who was taking amlodipine, had gingival overgrowth and swelling on examination. No specific periodontal treatment was provided to the patient for the GO; however, the amlodipine was replaced with an ACE inhibitor after consultation with her medical practitioner. Within two months, the suspension of amlodipine resulted in a significant improvement in her periodontal condition. Failure to control the hypertension caused the physician to re-prescribe amlodipine. After three months, the gingival overgrowth returned; however, its severity was less when compared with the original periodontal condition, due to reduction in drug dose and periodontal therapy. This experience suggests that temporary suspension of a drug which can induce GO can improve the periodontal condition without the aid of surgical treatment.

Effects of combined oral treatments with cyclosporine A and nifedipine or diltiazem on drug-induced gingival overgrowth in rats

BACKGROUND

Cyclosporine A (CsA) and calcium channel blockers induce gingival overgrowth in humans and animals. Recently, nifedipine and diltiazem have often been used to control CsA-related hypertension in organ transplant patients. The purpose of this study was to examine the effects of a combined oral treatment of CsA and nifedipine or diltiazem on the severity of gingival overgrowth in rats.

METHODS

Fifteen-day-old Fischer rats were treated orally with single or combined applications of CsA, nifedipine, and/or diltiazem for 40 days; and induced gingival overgrowth, rat growth, and blood drug levels were compared among the different experimental groups. The experiment consisted of 6 groups: one control group (group A) and 5 test groups treated with CsA (group B), nifedipine (group C), and diltiazem (group D), as well as those concurrently treated with CsA and nifedipine (group E), and CsA and diltiazem (group F). Gingival overgrowth was determined by measuring the depth of the gingival sulcus.

RESULTS

The mandibular buccal gingival sulcus depth of group A was 365 +/- 41.2 microm. Among the test groups, the most remarkable gingival overgrowth was seen in group E (1,020 +/- 63.3 microm), followed by group F (895 +/- 43.8 microm), group B (870 +/- 48.3 microm), group C (525 +/- 116 microm), and then group D (505 +/- 83.2 microm). Rat body weight gain was reduced significantly by oral CsA treatment. Neither nifedipine nor diltiazem suppressed rat growth when used independently; however, rat growth reduced by CsA was further suppressed by a combined use of diltiazem, but not nifedipine. CsA blood levels were reduced by concurrent oral treatment with nifedipine or diltiazem along with the blood levels of those calcium channel blockers when treatment was in combination with CsA.

CONCLUSIONS

These results suggest that gingival overgrowth is induced in rats as a side effect of CsA, nifedipine, or diltiazem, and the combined use of these drugs influences rat growth, blood drug levels, and the severity of gingival overgrowth.

Role of medullasin in nifedipine-induced gingival overgrowth in rats

To clarify the possible pathophysiological role of medullasin, a neutrophil elastase-like proteinase, in nifedipine (NF)-induced gingival overgrowth, a rat model of gingival overgrowth was first established using a diet containing NF. The relation between histopathological changes and the distribution of the proteinase was then investigated. Thirty-two, specific pathogen-free 20 day-old, male, Fisher 344 rats were fed a diet containing NF and killed at 2, 8, 16 and 32 weeks. Control rats (n = 32) were fed the same diet but without the drug. The mandible of each rat was resected and sectioned at 4-microm thickness buccolingually between the first and second molars. Computer image analysis was used to evaluate the extent of overgrowth in the approximal gingiva of each sample. To examine medullasin activity, the mean percentage of medullasin-positive cells per total cells counted in the pocket epithelium and the connective tissue adjacent to the epithelium of approximal gingiva was determined immunohistochemically. The height of the mid-portion and the area in NF-treated group increased significantly with time (with the exception of area at 2 weeks) compared with the corresponding regions in the control group. A marked inflammatory-cell infiltration and elongated rete pegs, especially in the mid-portion of approximal gingiva, were seen in the NF-treated group. The mean percentages of medullasin-positive cells in the NF-treated group at 8, 16 and 32 weeks were significantly higher than those of the control. Although medullasin-positive cells were mainly neutrophils, in several samples of the NF-treated group they were recognized as macrophage-like. These findings suggest that medullasin may be involved in host defence and immunoregulation in a NF-induced rat model of gingival overgrowth.

Nifedipine-induced gingival overgrowth in rats: brief review and experimental study

The first case report of gingival overgrowth induced by nifedipine (NIF), a calcium-beta blocker, was in 1984. However, the association between gingival alterations and the drug therapy of sodium diphenyl hydantoinate was initially described in 1939. The purpose of the experimental study was to examine the effect of NIF on gingival morphology in an animal model. Forty-five male Sprague-Dawley rats were randomly divided into 3 groups. Animals in each group daily received NIF in dimethyl sulfoxide by gastric feeding at a dosage of 0 (control), 30, or 50 mg/kg body weight for 9 weeks. Gingival gross morphology was assessed tri-weekly from stone models obtained from the mandibular incisal region. Animals were sacrificed at the end of study and tissue blocks were processed for histopathologic and histometric evaluation. Histometric analysis was performed at 5 selected tissue levels. Macro- and microscopic significantly increased gingival dimensions were demonstrated in NIF-treated animals compared to control. Although a fibrovascular tissue was observed in the tooth-gingiva interface for both NIF-treated and control animals, it was thicker and appeared earlier in NIF-treated animals. The results of the present study suggest that gingival overgrowth can be induced by NIF in rats and that the gingival overgrowth appears dose dependent.

Medication induced gingival overgrowth

A number of idiopathic, pathological and pharmacological reactions may result in an overgrowth of the gingiva. This review concentrates on those overgrowths associated with various pharmacological agents. The pharmaco-kinetics and side effects of each drug associated with gingival overgrowth are discussed along with the clinical and histological features and treatment. By examining the possible pathogeneses for these overgrowths we propose a unifying hypothesis for the causation based around inhibition of apoptosis and decreased collagenase activity modulated by cytoplasmic calcium.

The clinical effects of nifedipine on periodontal status

The present study was conducted to determine the clinical effects of nifedipine on the gingiva of 97 patients. Patients were examined for changes in periodontal status and divided into subgroups, based on their age, gender, duration of drug intake, presence/absence of plaque and gingival inflammation, and according to the presence and severity of gingival overgrowth. Gingival overgrowth was noticed in 29% of the patients. Among the recorded parameters, duration of drug intake, presence/severity of gingival inflammation, and gender seemed to have the greatest effect on the development of gingival overgrowth. Patients with higher gingival inflammation scores, those on nifedipine medication for more than 4 years, and males were likely to have an increased tendency for higher incidence and severity of gingival overgrowth. The findings of the present study suggest that nifedipine medication induces gingival overgrowth and that certain local factors are involved in the pathogenesis of drug-induced gingival overgrowth. However, individual ability and sensitivity to metabolize the drug and its metabolites also seem to be important etiological factors.

Positive correlation between blood cyclosporin A level and severity of gingival overgrowth in rats

Cyclosporin a is a drug used to control rejection of organ transplantation and autoimmune diseases; however, it has also been implicated in gingival overgrowth. The present study investigates the relationship between severity of gingival overgrowth and blood cyclosporin A (CsA) levels in Fischer rats treated orally with CsA. Thirty-six 15-day-old male rats were divided into six experimental groups and given powdered rat chow containing 0, 50, 100, 200, 300, and 400 micrograms CsA/g diet ad libitum for 40 days. At the end of the 40-day treatment period, whole blood samples were collected from each rat for assessment of CsA levels. The rats were then sacrificed and the gingival sulcus depth (pseudopocket) around mandibular molars measured to estimate gingival overgrowth. The blood levels of CsA in rats increased with increasing amounts of CsA provided in their food. A 100% incidence in gingival overgrowth was induced in all the rats treated orally with CsA. The overgrowth was more severe in buccal than in lingual gingiva. A significantly positive correlation was found between gingival sulcus depth and the blood CsA level (rs = 0.914, P < 0.0001; Spearman's correlation coefficient by rank). On histological examination, the overgrown gingiva consisted of a thickened epithelial layer and an accumulation of subepithelial fibrous connective tissue components without marked distortion of their proportion.

Pathogenesis of drug-induced gingival overgrowth. A review of studies in the rat model

Drug-induced gingival overgrowth is a side effect associated principally with 3 types of drugs: anticonvulsant (phenytoin), immunosuppressant (cyclosporine A), and various calcium channel blockers (nifedipine, verapamil, diltiazem). In this review, we describe the features of phenytoin-, cyclosporine A- and nifedipine-induced gingival overgrowth in rats and discuss factors influencing the onset and severity of these disorders. There are several features common to the gingival overgrowth induced by these drugs: 1) gingival overgrowth is more conspicuous in the buccal than in the lingual gingiva and less severe in the maxilla than in the mandible; 2) once the blood concentration of the drug reaches a certain level as a result of increasing the dose, the incidence of gingival overgrowth is 100% and its severity is dependent on the blood level, the most severe overgrowth being induced by cyclosporine A; 3) the duration of drug administration for maximal gingival overgrowth to develop is about 40 days; 4) the gingival overgrowth regresses spontaneously after discontinuing the drug; 5) accumulation of dental plaque is not essential for the onset of overgrowth, but plays a role in its severity; and 6) more severe overgrowth is induced in young than in old rats. Furthermore, male rats are more susceptible than females to nifedipine-induced gingival overgrowth. These results suggest that drug-induced gingival overgrowth in rats is dependent on the oral drug dose, blood drug level, age, and sex and that preexisting gingival inflammation is a factor relevant to its severity. Since these factors have also been suggested to be important determinants for human drug-induced gingival overgrowth, the rat model may prove valuable in the future for elucidating the molecular pathogenesis of the disorder.

Cyclosporin- and nifedipine-induced gingival overgrowth in renal transplant patients: correlations with periodontal and pharmacological parameters, and HLA-antigens

The factors associated with cyclosporin A (CsA)- and nifedipine (Nif)-induced gingival overgrowth were investigated in 113 renal transplant recipients receiving CsA alone (Group 1) [n = 61], CsA and Nif (Group 2) [n = 28], or azathioprine (Aza) (Control Group) [n = 24]. Periodontal and pharmacological parameters were assessed for each patient. The patients with a gingival overgrowth index (GOI) score >1 were considered responders (R); those with a score </= 1 were non-responders (NR). Gingival overgrowth occurred in 33.7% of the patients in Groups 1 and 2; 60% of the responders were receiving CsA+Nif. In R, no relationship was found between the GOI and the periodontal and pharmacological parameters, and although there was a trend towards an increased presence of HLA-A19 antigen (chi-square=4.40; P=0.04; RR=2.86), no significant difference was found between R and NR (Pc>0.05). It is concluded that the prevalence and severity of gingival overgrowth are greater in patients receiving CsA+Nif. As overgrowth appeared to be unrelated to local irritants, gingival inflammation or pharmacological parameters, it may be related to individual susceptibility.

Factors influencing nifedipine-induced gingival overgrowth in rats

Factors such as age, the dose of nifedipine administered in the diet, serum drug level, duration of drug administration, and sex which may influence nifedipine-induced gingival overgrowth were examined in a rat model using 20-, 50-, and 90-days-old male and female rats. Oral administration of nifedipine (50 to 250 mg/kg diet) increased the serum level of the drug in a dose-dependent manner in both males and females. However, a higher serum level was required in females than males to attain the same degree of gingival overgrowth. The minimum dietary concentrations of the drug required to elicit gingival overgrowth in males and females were 150 and 100 mg/kg, respectively, which gave respective minimum serum levels of 800 and 1100 ng/ml. The degree of overgrowth depended on the serum concentration of the drug after it had reached the required minimum in male and female animals. Administration of nifedipine (250 mg/kg diet) for 20 days was enough to induce maximal overgrowth, but this induction occurred only in rats that started to receive the drug when they were 20 days old, not in those that started at 50 and 90 days of age for the same administration period of 55 days, and the overgrowth regressed and the gingiva were normal 40 days after ceasing drug administration. These results suggest that gingival overgrowth occurred in accordance with the drug concentration in the diet, as well as that in the serum, and was more likely to occur in males and younger individuals.