Assessment of Alloxan-Induced Diabetic Rats as a Periodontal Disease Model Using a Selective Cyclooxygenase (COX)-2 Inhibitor.

Several recent studies have reported that alloxan-treated rats with long-term hyperglycemia can develop naturally occurring periodontal disease (PD). Our previous studies detected dental caries in the same model. Therefore, these two lesions of different etiologies are expected to occur concurrently. In this study, we evaluated the use of diabetic rats as a PD model by employing a selective COX-2 inhibitor reported to be effective against PD. Six-week-old female F344 rats were divided into 3 groups: intact rats (control), alloxan-induced diabetic rats fed a standard diet (AL) and alloxan-induced diabetic rats fed a diet containing 0.01% etodolac (AL+Et). The animals were euthanized at 26 weeks of age, and their oral tissues were examined histopathologically. Gingivitis, marginal periodontitis and alveolar bone resorption were markedly enhanced along with dental caries in the AL group compared with the control group. However, the COX-2 inhibitor had no effect on periodontal inflammation in the AL+Et group. In addition, in the AL group, periodontitis was notably nonexistent around the normal molars, and gingivitis was scarcely worse than that in the control group. In the diabetic rats, the progression of periodontal inflammation was closely correlated with the severity of adjacent dental caries, and marginal periodontitis was frequently continuous with apical periodontitis. In conclusion, an alloxan-induced diabetic rat is not a model of PD but of dental caries. It is probable that in this model, hyperglycemia may enable crown caries to progress to apical periodontitis, while the associated inflammation may rostrally expand to surrounding periodontal tissue.

Glycemic control with insulin prevents progression of dental caries and caries-related periodontitis in diabetic WBN/KobSlc rats.

We have previously reported that dental caries progress in spontaneously and chemically induced diabetic rodent models. The aim of this study was to clarify the relationship between hyperglycemia and dental caries by evaluating the preventive effect of glycemic control with insulin on the progression of the lesions in diabetic rats. Male WBN/KobSlc rats aged 15 weeks were divided into groups of spontaneously diabetic rats (intact group), spontaneously diabetic rats with insulin treatment (INS group), alloxan-induced prolonged diabetic rats (AL group), and alloxan-induced prolonged diabetic rats with insulin treatment (AL + INS group). The animals were killed at 90 weeks of age, and their oral tissue was examined. Dental caries and periodontitis were frequently detected in the intact group, and the lesions were enhanced in the AL group (in which there was an increased duration of diabetes). Meanwhile, glycemic control with insulin reduced the incidence and severity of dental caries and periodontitis in the INS group, and the effects became more pronounced in the AL + INS group. In conclusion, glycemic control by insulin prevented the progression of dental caries and caries-related periodontitis in the diabetic rats.

Multiple respiratory complications in a patient with Charcot-Marie-Tooth disease with MFN2 mutation.

Charcot-Marie-Tooth disease (CMT) is a hereditary peripheral neuropathy characterized by progressive atrophy of distal muscles. Respiratory complications are rare. We present a case of a 49-year-old male with childhood-onset CMT bearing a genetic mutation of MFN2. He had difficulty breathing when he was 46. Imaging examination revealed complications of phrenic nerve paralysis and pneumothorax with a funnel chest. Respiratory function test demonstrated severe restrictive ventilatory impairment. Polysomnography supported the diagnosis of mild sleep apnea syndrome. Noninvasive positive pressure ventilation successfully reduced respiratory symptoms. To our knowledge, this is the first demonstration of multiple respiratory complications in a CMT patient.

Eosinophilic sialoadenitis in a patient with severe asthma: a case report.

Activated eosinophils can infiltrate various tissues and cause inflammatory tissue damage. Asthma is a typical type of eosinophilic inflammatory disease that occurs in the respiratory system. Eosinophilic sialodochitis and sialoadenitis of the salivary gland are rare diseases clinically characterized by painful swelling. In this report, we present a 68-year-old woman with asthma who presented to our hospital with mandibular swelling. Her asthma had been well controlled with an inhaled combination of a corticosteroid and a long-acting ß2 agonist, although she reported a past history of frequent asthma attacks and hospitalization. Laboratory investigation on admission revealed blood eosinophilia (2,673/µL), high levels of total immunoglobulin E (390 U/mL) and immunoglobulin G4 (183 mg/dL). Bone marrow examination showed no evidence of eosinophilic neoplasia. Histological examination of her minor salivary glands disclosed an infiltration of mixed lymphocytes and eosinophils. Chromatolytic eosinophils with Charcot-Leyden crystals were also observed within the edematous dermis and fibrous tissues surrounding the minor salivary gland. The patient was diagnosed with eosinophilic sialoadenitis. Treatment with oral corticosteroids (0.5 mg/kg/day) was initiated. Thereafter, the mandibular swelling improved. This report describes a rare case of eosinophilic sialoadenitis in a patient with severe eosinophilic asthma, for which histopathological and immunefluorescence microscopic analyses were performed.

Morphological study on dental caries induced in WBN/KobSlc rats (Rattus norvegicus) fed a standard laboratory diet.

In our previous studies, WBN/KobSlc was characterized as a rat strain in which only males began to develop pancreatitis, and then presented with diabetic symptoms. In the course of studying their pancreatic inflammation, we detected molar caries in prediabetic males feeding on a standard diet (CRF-1) widely used for experimental animals. The purpose of this study is to confirm whether the WBN/KobSlc strain is caries-susceptible to the diet reported to be non-cariogenic, and to examine the effect of a prediabetic condition on their dental caries. For a morphological study, 25 male WBN/KobSlc rats aged 3.2-7.8 months and 24 females of the same strain aged 3.3-6.6 months were used, along with 10 males and 10 females of 8.2-month-old F344 rats. Marked dental caries were detected in the mandibular molars of male and female WBN/KobSlc rats regardless of pancreatitis, although no similar changes were observed in any teeth of the F344 strain fed the same diet. Soft X-ray examination revealed that the caries began in the crown and progressed horizontally and vertically, and that a severe radiolucent lesion extensively expanded to the entire crown, corresponding to a macroscopically deleted molar. The caries had gradually developed mainly in the second mandibular molar from more than 3.5 months of age, while none were seen in any rats before that time. The WBN/KobSlc rats were caries-susceptible even to the standard laboratory diet, and pancreatitis was not directly associated with the onset of dental caries in this strain.

The effect of food hardness on the development of dental caries in alloxan-induced diabetic rats.

We have previously shown that dental caries may be produced in diabetic rodent models fed with noncariogenic standard diets; however, many studies usually add large amounts of sugar to the diet to induce dental caries. Moreover, the physical properties of cariogenic diets have been reported as an important factor in the formation of caries. The aim of this study was to clarify the effect of the hardness of non-cariogenic diets on the development of dental caries in diabetic rodents. Seven-week-old female F344 rats were divided into 4 groups: intact rats fed with a standard pelletized or powdered diet and alloxan-induced diabetic rats fed with a standard pelletized or powdered diet. All of the rats were sacrificed at 52 weeks of age for morphological examinations on their dental tissue. Dental caries had developed and extended to all the molars in the diabetic rats that were fed with both the pelletized and powdered diets. Moreover, the lesion was significantly enhanced in the powdered diet group compared to that in the pelletized diet group. In conclusion, food hardness is an important factor influencing the development of dental caries in diabetic rats.

Alloxan-induced hyperglycemia causes rapid-onset and progressive dental caries and periodontitis in F344 rats.

We have previously shown that diabetes increases dental caries, and periodontitis might be a secondary change resulting from dental caries in spontaneous diabetic rodent models. However, the lesions in these models were slow to manifest, and the intensity and frequency were mild and varied among individuals. The goal of this study was to confirm the reproducibility of caries development in chemically induced diabetic rats and investigate whether alloxan, which induces immediate and severe hyperglycemia in experimental animals, increases the lesions. Female F344 rats were examined 13 and 26 weeks after dosing of alloxan. Alloxan injection induced severe hyperglycemia in two-thirds of the rats. Progressive molar caries and periodontitis were already induced in all diabetic rats 13 weeks after dosing of alloxan, although the lesions were not observed in nondiabetic rats. Histopathologically, dental caries initially developed in the crown, then spread into the dental root, entered the periodontal connective tissue via the apical foramen, and progressed to periodontitis. In conclusion, alloxan-induced severe hyperglycemia is capable of causing rapid-onset and progressive dental caries and periodontitis in rats.

Diabetes enhances dental caries and apical periodontitis in caries-susceptible WBN/KobSlc rats.

Many epidemiologic studies have suggested that diabetes may be an important risk factor for periodontal disease. To determine whether diabetes induces or enhances periodontal disease or dental caries, dental tissue from diabetic male and nondiabetic female WBN/KobSlc rats and male and female age-matched nondiabetic F344 rats was analyzed morphologically and morphometrically for these 2 types of lesions. Soft X-ray examination revealed that the incidence and severity of both molar caries and alveolar bone resorption were much higher in male WBN/KobSlc rats with chronic diabetes than in nondiabetic female rats of the same strain. Histopathologic examination showed that dental caries progressed from acute to subacute inflammation due to bacterial infections and necrosis in the pulp when the caries penetrated the dentin. In the most advanced stage of dental caries, inflammatory changes caused root abscess and subsequent apical periodontitis, with the formation of granulation tissue around the dental root. Inflammatory changes resulted in resorption of alveolar bone and correlated well with the severity of molar caries. Our results suggest that diabetic conditions enhance dental caries in WBN/KobSlc rats and that periodontal lesions may result from the apical periodontitis that is secondary to dental caries.