Indigo plant improves serum lipid profiles

We investigated the effects of Polygonum tinctorium Lour (PTL), a plant commonly known as indigo, on biological parameters in an animal model of high-fat diet-induced obesity. Wistar rats fed a high-fat diet and treated with PTL showed lower serum levels of triglycerides and total cholesterol levels and a higher serum levels of HDL cholesterol than those in Wistar rats fed a high-fat diet without PTL treatment. The weight of mesenteric fat in PTL-treated rats was decreased compared to that in control rats not treated with PTL. In addition, energy metabolic rate in the dark period, but not in the light period, in PTL-treated rats was higher than that in control rats. Although a significant difference was not observed, body weight in PTL-treated rats tended to be decreased compared to that in control rats. The results show that PTL improves serum lipid profiles in Wistar rats with high-fat diet-induced obesity

Influence of Reactive Oxygen Species on Wound Healing and Tissue Regeneration in Periodontal and Peri-Implant Tissues in Diabetic Patients

Diabetes mellitus (DM) is associated with periodontal disease. Clinically, periodontal treatment is less effective for patients with DM. Oxidative stress is one of the mechanisms that link DM to periodontitis. The production of reactive oxygen species (ROS) is increased in the periodontal tissues of patients with DM and is involved in the development of insulin resistance in periodontal tissues. Insulin resistance decreases Akt activation and inhibits cell proliferation and angiogenesis. This results in the deterioration of wound healing and tissue repair in periodontal tissues. Antioxidants and insulin resistance ameliorants may inhibit ROS production and improve wound healing, which is worsened by DM. This manuscript provides a comprehensive review of the most recent basic and clinical evidence regarding the generation of ROS in periodontal tissues resulting from microbial challenge and DM. This study also delves into the impact of oxidative stress on wound healing in the context of periodontal and dental implant therapies. Furthermore, it discusses the potential benefits of administering antioxidants and anti-insulin resistance medications, which have been shown to counteract ROS production and inflammation. This approach may potentially enhance wound healing, especially in cases exacerbated by hyperglycemic conditions

Periodontal regenerative effect of enamel matrix derivative in diabetes.

The present study aimed to investigate the periodontal regenerative effect of enamel matrix derivative (EMD) in diabetes. Thirty-six rats were assigned to streptozotocin-induced diabetes or control (non-diabetic) groups. Three-wall intrabony defects were surgically generated in the bilateral maxilla molar, followed by application of EMD or saline. Primary wound closure and defect fill were evaluated via histomorphological analysis and micro-computed tomography. mRNA expression levels of inflammatory and angiogenic factors in the defects were quantified via real-time polymerase chain reaction. Gingival fibroblasts were isolated from control animals and cultured in high-glucose (HG) or control medium. The effects of EMD on insulin resistance and PI3K/Akt/VEGF signaling were evaluated. The achievement rate of primary closure and the parameters of defect fill were significantly higher at EMD-treated site than at EMD-untreated sites in both diabetic and non-diabetic rats, although defect fill in the diabetic groups was significantly lower in the control groups on two-way repeated-measures analysis of variance (for both, p<0.05). Newly formed bone and cementum were significantly increased at EMD-treated sites in diabetic rats than at EMD-untreated sites in control rats (for both, p<0.05). Vegf was significantly upregulated at EMD-treated sites in both diabetic and non-diabetic rats (for both, p<0.05). In vitro, insulin or EMD-induced Akt phosphorylation was significantly lower in cells cultured in HG medium (p<0.05). EMD-mediated Vegf upregulation was suppressed by the Akt inhibitor wortmannin, although the effect was significantly lower in HG medium (p<0.01). In conclusion, EMD might promote periodontal tissue regeneration via Akt/VEGF signaling, even in a diabetic condition

Impact of diabetes on gingival wound healing via oxidative stress

<div><p>The aim of this study is to investigate the mechanisms linking high glucose to gingival wound healing. Bilateral wounds were created in the palatal gingiva adjacent to maxillary molars of control rats and rats with streptozotocin-induced diabetes. After evaluating postsurgical wound closure by digital imaging, the maxillae including wounds were resected for histological examinations. mRNA expressions of angiogenesis, inflammation, and oxidative stress markers in the surgical sites were quantified by real-time polymerase chain reaction. Primary fibroblast culture from the gingiva of both rats was performed in high glucose and normal medium. <i>In vitro</i> wound healing and cell proliferation assays were performed. Oxidative stress marker mRNA expressions and reactive oxygen species production were measured. Insulin resistance was evaluated via PI3K/Akt and MAPK/Erk signaling following insulin stimulation using Western blotting. To clarify oxidative stress involvement in high glucose culture and cells of diabetic rats, cells underwent N-acetyl-L-cysteine treatment; subsequent Akt activity was measured. Wound healing in diabetic rats was significantly delayed compared with that in control rats. <i>Nox1</i>, <i>Nox2</i>, <i>Nox4</i>, <i>p-47</i>, and <i>tumor necrosis factor-α</i> mRNA levels were significantly higher at baseline in diabetic rats than in control rats. <i>In vitro</i> study showed that cell proliferation and migration significantly decreased in diabetic and high glucose culture groups compared with control groups. <i>Nox1</i>, <i>Nox2</i>, <i>Nox4</i>, and <i>p47</i> expressions and reactive oxygen species production were significantly higher in diabetic and high glucose culture groups than in control groups. Akt phosphorylation decreased in the high glucose groups compared with the control groups. Erk1/2 phosphorylation increased in the high glucose groups, with or without insulin treatment, compared with the control groups. Impaired Akt phosphorylation partially normalized after antioxidant N-acetyl-L-cysteine treatment. Thus, delayed gingival wound healing in diabetic rats occurred because of impaired fibroblast proliferation and migration. Fibroblast dysfunction may occur owing to high glucose-induced insulin resistance via oxidative stress.</p></div

Cell proliferation analysis (EdU).

<p>Cell proliferation measured by the EdU assay was significantly less in the diabetes mellitus (DM) groups than in the control groups. (A) Representative immunofluorescence images of EdU incorporated into mitochondrial DNA, Hoechst 33342, and merged images. EdU activation was decreased in the DM groups. (B) Among the control and DM groups, cells incubated at a high glucose concentration had a significantly lower cell proliferation than those incubated at the control glucose concentration. Data are presented as mean ± SD; *<i>p</i> < 0.05 (Tukey–Kramer test). This finding was confirmed in four independent experiments.</p

<i>In vitro</i> mRNA expression.

<p>mRNA expression of the oxidative stress markers <i>Nox1</i>, <i>Nox2</i>, <i>Nox4</i>, and <i>p47</i> in cells from control and diabetes mellitus (DM) rats was quantified by real-time quantitative polymerase chain reaction (PCR). Oxidative stress markers were significantly increased in the DM and high glucose groups. Data are presented as means ± SD. *<i>p</i> < 0.05 (Tukey-Kramer test). This finding was confirmed in four independent experiments.</p

Morphometric measurements.

<p>(A) Study design. Diabetes was induced by intraperitoneal injection of streptozotocin (STZ). Seventy-two hours after injection, rats with fasting glucose levels above 350 mg/dL were used as diabetic rats. In total, 36 animals (6 per group per time point) and 72 wound sites (2 per animal) were evaluated. (B) Illustration of a palatal wound. Bilateral standardized wounds were created in the palatal gingiva adjacent to maxillary molars. M1: first molar. M2: second molar. M3: third molar. (C) Standardized photographs of wound sites at 0, 3, 7, and 21 days in control and diabetes mellitus (DM) groups. On days 7 and 21, delay of wound healing was observed in the DM group. On day 21, the wound sites were completely closed in the control group but they were still not closed in the DM group. (D) Normalized closed wound areas in control and DM groups. The area of wound closure was measured. Measurements were independently made by two blinded examiners (K.M. and K.T.), and the data were analyzed. Wound closing was delayed on days 7, 14, and 21 in the DM group. Data are presented as means ± SD (n = 6). *<i>p</i> < 0.05 (<i>t</i>-test).</p

Body weight, fasting blood glucose level, plasma insulin level, and urine 8-OHdG level in rats changed due to streptozotocin medication (60 mg/kg).

<p>Body weight, fasting blood glucose level, plasma insulin level, and urine 8-OHdG level in rats changed due to streptozotocin medication (60 mg/kg).</p

Verification of the effect of various glucose concentrations on cytotoxicity and <i>in vitro</i> wound healing assay in primary cultured rat gingival fibroblasts.

<p>Cytotoxicity and cell migration after incubation at various glucose concentrations were assessed in gingival fibroblasts from control rats. (A) Cytotoxicity was measured by lactate dehydrogenase (LDH) release in the supernatant. The results revealed a significant cytotoxicity with incubation at 100 mM glucose concentration. There was a tendency of increased cytotoxicity dose-dependent manner, although the difference was not statistically significant. (B) Effects of various glucose concentrations on <i>in vitro</i> wound healing assay. The relative cell migration area in the 75 mM group significantly decreased from 9 to 36 h compared with that in the 15 mM group. (C) The area under the curve (AUC) was calculated from the line graph. The AUC was the largest in the 15 mM group. The AUC of the 75 mM group was significantly smaller than that of the 15 mM group. Data are presented as mean ± SD. *<i>p</i> < 0.05 (Tukey–Kramer test). This finding was confirmed in three independent experiments.</p

Fluorescence determination of oxidative stress.

<p>CM-H₂DCFDA staining showed that high glucose concentration induced oxidative stress. Oxidative stress measured by CM-H₂DCFDA assay was significantly higher in the diabetes mellitus (DM) groups than in the control groups. (A) Representative immunofluorescence images. Immunofluorescence by ROS was assessed by digital fluorescence microscopy. ROS activation was increased in the DM groups. (B) Among the control and DM groups, cells incubated at a high glucose concentration had showed a significantly higher ROS production than those incubated at the control glucose concentration. Data are presented as mean ± SD; *<i>p</i> < 0.05 (Tukey–Kramer test). This finding was confirmed in four independent experiments.</p