Combined resveratrol and vitamin D treatment ameliorate inflammation-related liver fibrosis, ER stress, and apoptosis in a high-fructose diet/streptozotocin-induced T2DM model.

A high fructose diet is a major cause of diabetes and various metabolic disorders, including fatty liver. In this study, we investigated the effects of resveratrol and vitamin D (VitD) treatments on endoplasmic reticulum (ER) stress, oxidative stress, inflammation, apoptosis, and liver regeneration in a rat model of type 2 diabetes mellitus, namely, T2DM Sprague-Dawley rats. This T2DM rat model was created through a combination treatment of a 10% fructose diet and 40 mg/kg streptozotocin (STZ). Resveratrol (1 mg/kg/day) and VitD (170/IU/week) were administered alone and in combination to both the diabetic and control groups. Immunohistochemical staining was performed to evaluate PCNA, NF-κB, TNF-α, IL-6, IL-1ß, GRP78, and active caspase-3 in liver tissue. The TUNEL method and Sirius red staining were used to determine apoptosis and fibrosis, respectively. G6PD, 6-PGD, GR, and GST activities were measured to determine oxidative stress status. We found that the expressions of cytokines (TNF-α, IL-6, and IL-1ß) correlated with NF-κB activation and were significantly increased in the T2DM rats. Increased GRP78 expression, indicating ER stress, increased in apoptotic cells, enhanced caspase-3 activation, and collagen accumulation surrounding the central vein were observed in the T2DM group compared with the other groups. The combination VitD + resveratrol treatment improved antioxidant defense via increasing G6PD, 6-PGD, GR, and GST activities compared to the diabetic groups. We concluded that the combined administration of resveratrol with VitD ameliorates the adverse effects of T2DM by regulating blood glucose levels, increasing antioxidant defense mechanisms, controlling ER stress, enhancing tissue regeneration, improving inflammation, and reducing apoptosis in liver cells. In conclusion, this study indicates that the combination treatment of resveratrol + VitD can be a beneficial option for preventing liver damage in fructose-induced T2DM.

Synergistic Effect of Apigenin and Curcumin on Apoptosis, Paraptosis and Autophagy-related Cell Death in HeLa Cells.

BACKGROUND/AIM: We aimed to investigate the synergistic effects of apigenin and curcumin on the cross-talk between apoptosis and autophagic cell death, as well as on paraptosis in HeLa cells. MATERIALS AND METHODS: Cell viability was measured using the MTT assay. Synergistic effects were measured using the Bliss independence model. qRT-PCR was used to study the expression of genes related to apoptosis, autophagic cell death, and cross-talk. GRP78/BiP immunostaining was used to identify endoplasmic reticulum (ER) stress. RESULTS: Treatment with a combination of apigenin and curcumin increased the expression levels of genes related to cell death in HeLa cells 1.29- to 27.6-fold. The combination of curcumin and apigenin showed a synergistic anti-tumor effect via cross-talk between processes leading to apoptosis and autophagic cell death, as well as ER stress-associated paraptosis. GRP78 expression was down-regulated, and massive cytoplasmic vacuolization was observed in HeLa cells. CONCLUSION: The combination of curcumin and apigenin is an effective potential therapeutic for cervical cancers.

Transdifferentiation of both intra- and extra-islet cells into beta cells in nicotinamide treated neonatal diabetic rats: An in situ hybridization and double immunohistochemical study.

We aimed to study the effect of nicotinamide (NA) on beta (ß)-cell regeneration and apoptosis in streptozotocin induced neonatal rats (n-STZ). Three groups were performed: Control group, n2-STZ group (100 mg/kg STZ on the second day-after birth), n2-STZ + NA group (STZ;100 mg/kg + NA;500 mg/kg/day for 5 days). The pancreatic tissue sections were immunostained with insulin, glucagon, somatostatin, Pdx1, Notch1 and active caspase-3 antibodies, and double immunostained with insulin/PCNA, insulin/glucagon and insulin/somatostatin antibodies. In situ hybridization carried out with insulin probe. Apoptotic ß-cell were shown by TUNEL assay, followed by immunostaining. The number of insulin/PCNA, insulin/glucagon and insulin/somatostatin double-positive cells significantly increased in n2-STZ + NA group compared with the other groups (p < 0.001). n2- STZ group had lower number of insulin and Pdx1 positive cells in islets, compared to NA treated diabetics. The insulin and Pdx1 immun positive cells were located in the small clusters or scattered through the exocrine tissue and around to ducts in n2-STZ + NA group. Notch1 positive cell numbers were increased, whereas caspase-3 and TUNEL positive ß-cell numbers were decreased in n2-STZ + NA group. NA treatment induces the neogenic insulin positive islets orginated from the differentiation of ductal progenitor cells, transdifferentiation of acinar cells into ß cells, and transformation of potent precursor cells and centroacinar cells via the activated Notch expression into ß-cells in n-STZ rats.

Evaluation of the in vivo wound healing potential of the lipid fraction from activated platelet-rich plasma.

Previous in vitro studies suggest a direct relevance for the peptide-free lipid fraction (LF) of platelet-rich plasma (PRP) in biological mechanisms related to wound healing. However, there are no scientific reports to date on the wound healing activities of this lipid component in vivo. Thus, the present study provides a scientific evaluation for the wound healing potential of the lipid portion of the activated PRP. For the wound healing activity assessment, in vivo full-thickness excisional wounds were created on the dorsal skin of Sprague-Dawley rats. Lipid extract from pooled PRP was applied topically to the wounds on 0, 3, and 7 days after injury. Histological assessment of epidermal and dermal regeneration, granulation tissue thickness and angiogenesis by Sirius red and Masson's trichrome staining, in addition to immunohistochemical staining for transforming growth factor beta-1 (TGF-ß1), collagen type I (COL I), and collagen type III (COL III) were performed on skin biopsies at 3, 7 and 14 days. The total histological scores of the LF group were significantly higher than the 25% dimethylsulfoxide-control group. According to the immunohistochemical staining, the observed expression changes for TGF-ß1, COL I and III at 3, 7, and 14 days after wounding were significantly better in the study group than the control group. Furthermore, COL I/III ratio in the lipid extract-treated group at day 14 was much higher than that of the control group. Meanwhile, analysis of the data also indicated that the LF has less positive effects on all evaluated parameters than PRP. From the present data, it could be concluded that the peptide-free LF of PRP has potent wound healing capacity in vivo for cutaneous wounds, although not as much as that of PRP. Strengthening our understanding of the wound healing potential of lipid components of PRP and platelet-derived lipid factors may provide new avenues for improving the healing process of a wound with elevated protease activity.

DPP4 inhibitor induces beta cell regeneration and DDR-1 protein expression as an endocrine progenitor cell marker in neonatal STZ-diabetic rats.

BACKGROUND: We aim to investigate the effects of dipeptidyl-peptidase-4 inhibitor (Vildagliptin-VG) on DDR-1 as a marker for endocrine progenitor cells, ß-cell regeneration, and apoptosis in neonatal streptozotocin (n2-STZ) diabetics. METHODS: Neonatal rats were divided into two main groups as short- and long-term treatment, each consisted of four groups; (1) Control, (2) n2-STZ diabetic (single dose of 100 mg/kg STZ at 2nd day of birth), (3) n2-STZ + VG (60 mg/kg/day VG orally; for 8 and 28 days), (4) VG (60 mg/kg/day orally; for 8 and 28 days). Blood glucose levels and body weights were measured, and the tissue sections were immunostained using insulin, glucagon, somatostatin, PCNA, Pdx-1 and DDR-1 antibodies. The TUNEL method was used for apoptosis. RESULTS: The number of ß cells in islets of the n2-STZ + VG group increased compared to the n2-STZ group; insulin (+) cells were observed individually or as small clusters in exocrine tissue, between pancreatic duct epithelial cells, and around the ducts. The number of Pdx-1 and DDR-1 positive cells in islet and extra-islet pancreas tissue was elevated as a result of VG application compared to the STZ diabetic group; the number of double positive cells for DDR-1 and insulin increased in n2-STZ + VG rats. CONCLUSION: We showed that vildagliptin promotes ß cell neogenesis and regeneration, stimulates DDR-1 expression as an endocrine cell progenitor marker, suppresses apoptosis, induces islet cell proliferation and rearranges islet morphology in the n2-STZ diabetes model.

Resveratrol can prevent CCl4-induced liver injury by inhibiting Notch signaling pathway.

We investigated whether Notch signaling was increased in an experimental liver fibrosis model and examined the effects of resveratrol on Notch expression. Rats were divided into four groups: the control group, injected with physiological saline; the CCl4 group; the CCl4 plus resveratrol group; and the resveratrol group. After treatment, immunostaining was performed to detect Notch1, Notch3, Notch4, transforming growth factor (TGF)-beta, alpha-smooth muscle actin (SMA), glial fibrillary acidic protein (GFAP), and proliferating cell nuclear antigen (PCNA), and TUNEL assays were performed to evaluate apoptosis. Sirius red staining was used to detect fibrosis. Samples were also biochemically evaluated for glutathione (GSH), glutathione peroxidase (GPx), catalase (CAT), lipid peroxidation, and protein oxidation. GSH, GPx, and catalase activities were significantly decreased (p⟨0.001) in the CCl4 group. Distinct collagen accumulation was detected around the central vein and portal areas, and numbers of Notch1-, Notch3-, and Notch4-positive cells were significantly increased (p⟨0.001) in fibrotic areas in the CCl4 group. Increased expression of Notch proteins in fibrotic areas may support the role of Notch in mediating signaling associated with liver fibrosis through activation of hepatic stellate and progenitor cells. In contrast, resveratrol prevented liver fibrosis by decreasing lipid peroxidation and may be effective for inhibiting Notch signaling.

The severity of internal carotid artery stenosis is associated with the cyclin-dependent kinase inhibitor 2A gene expression.

AIM: The INK4b-ARF-INK4a locus in the chromosome 9p21 region is known to play an important role in the development of atherosclerosis. The INK4/ARF transcript p16(INK4a) inhibits the activity of the cyclin-dependent kinases CDK4/CDK6 and arrests cell-cycle progression. CDK inhibitors also regulate G1/S phase progression in vascular smooth muscle cells(VSMCs) and may modulate the early stages of atherosclerosis. Therefore, we aimed to study the expression of the INK4/ARF locus genes CDKN2A and CDKN2BAS in order to examine the p16(INK4a) protein expression and the level of cell proliferation in carotid plaques and saphenous tissue samples. METHODS: A total of 50 patients(33 symptomatic subjects and 17 asymptomatic subjects) with carotid atherosclerosis CA) were studied. The CDKN2A and CDKN2BAS gene expression levels were determined using quantitative real-time polymerase chain reaction(qRT-PCR). All tissue sections were also analyzed for the p16(INK4a) and proliferating cell nuclear antigen(PCNA) protein expression using immunohistochemistry(IHC). RESULTS: The CDKN2A gene expression was significantly higher in the carotid plaques than in the saphenous tissues(p=0.009), whereas no such differences were observed in the CDKN2BAS transcripts(p=0.157). The carotid plaque CDKN2A mRNA levels were higher in the symptomatic patients than in the asymptomatic patients(p=0.050); this finding was also associated with the severity of internal carotid artery(ICA) stenosis(p=0.034). The p16(INK4a) immune(＋) cell counts in the carotid plaques were higher in the symptomatic patients than in the asymptomatic patients (p=0.056), as was the cell proliferation index(p=0.001). CONCLUSIONS: An increased CDKN2A gene expression in carotid plaques may increase the severity of ICA stenosis, thus raising the risk of atherosclerosis and contributing to the development of symptoms. In addition, the p16(INK4a) expression is associated with carotid atherosclerosis in various patient subgroups.

The role of clusterin on pancreatic beta cell regeneration after exendin-4 treatment in neonatal streptozotocin administrated rats.

We investigated the effects of exendin-4 (Ex4) treatment on expression of clusterin and ß cell regeneration in the endocrine pancreas in neonatal streptozotocin (nSTZ) diabetic rats. Three groups were used: (1) n2-STZ group; on the second day after birth 100mg/kg STZ was given i.p. to two groups of newborn rats, (2) n2-STZ+Ex4 group; 3µg/kg/day Ex4 was given for 5 days starting on the third day, and (3) control group. In situ hybridization for mRNAs of insulin and clusterin, double immunostaining for insulin/clusterin and insulin/BrdU were carried out. Immunostaining for insulin, glucagon, somatostatin, clusterin, synaptophysin and pdx-1 was performed. In the n2-STZ+Ex4 group, BrdU/insulin and insulin/clusterin immunopositive cells were significantly increased in the islets of Langerhans in comparison to the other groups. The areas occupied by the insulin mRNA and peptide positive cells and also pdx-1 immunopositive cells were decreased in the n2-STZ diabetic group compared with the other groups. The clusterin mRNA and protein positive cells, and also the glucagon and somatostatin cells, were significantly increased in the islets of the n2-STZ and the n2-STZ+Ex4 groups compared with the control group. The results show that Ex4 treatment induces new beta cell clusters via up-regulation of clusterin, which might be effective on beta-cell proliferation and neogenesis.

The effects of alpha lipoic acid on liver cells damages and apoptosis induced by polyunsaturated fatty acids.

We studied the effect of alpha-lipoic acid (ALA) on the liver cell damages and apoptosis by n-6 polyunsaturated fatty acids (PUFA) rich diet in young rats. 24 Wistar rats were divided into four groups. During the study, 12 of them (control) were fed with standard chow and other 12 (n-6) were fed with the food containing high-fat n-6 for 8 weeks. At the end of the fourth week, control and n-6 groups were randomly divided into two groups and then, 4 weeks, 35 mg/kg ALA are injected. Groups; control, control+ALA, n-6, n-6+ALA. The liver tissue glutathione (GSH) activity was determined. Immunohistochemistry for caspase-3 and TUNEL method for apoptosis were performed. The GSH levels have significantly decreased (p<0,001), and vacuolization in the hepatocytes, infiltration and the collagen accumulation around the central vein, hepatic stellate cells in the sinusoids have increased in n-6 group compared with the other groups. TUNEL (p<0,001) and caspase-3 (p<0,001) positive cells increased in n-6 group whereas all degenerative observations decreased in n-6+ALA group. Our results demonstrate that the feeding with n-6 PUFA causes fatty liver, fibrosis development, inflammations and apoptosis in the liver of young rats. ALA has a beneficial effects on these degenerative effects.

Protective effects of a calcium channel blocker on apoptosis in thymus of neonatal STZ-diabetic rats.

Streptozotocin (STZ) is known to induce insulin-dependent diabetes in experimental animals. In STZ-induced diabetes, atrophy of the thymus is caused by elevated intracellular calcium levels leading to apoptosis. Hyperglycemia is known to result in a decrease in numbers of T cells in the thymus and circulation. Intracellular calcium levels increase in diabetic animals after induction by STZ. Hyperglycemia inhibits Ca2+-ATPase and increases intracellular calcium levels. We have investigated apoptosis in thymus tissue of neonatal STZ (n-STZ)-diabetic rats and the effects of isradipine as a calcium channel blocker (CCB) on apoptosis. Five groups of newborn Wistar rats were used. On the second day after birth, 100 mg/kg STZ was given i.p. to the first two groups. The first group was n-STZ diabetic. To the second group, starting from the 12th week, 5 mg/kg/day isradipine (i.p) was given for 6 weeks. To the third group, the same dose of isradipine was given on the second day, followed by STZ treatment. The fourth group was non-diabetic and treated with 5 mg/kg/day isradipine for six weeks. The fifth group consisted of non-diabetic rats. To the sixth group, dexamethasone (5 mg/kg i.p.) was given to adult rats. For detection of apoptotic cells in paraffin-embedded thymus sections, the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labelling (TUNEL) assay was used. The DNA ladder method was performed for analysis of DNA fragmentation. In the isradipine-treated non-diabetic group, typical apoptotic banding patterns were found, whereas thick bands between 123 and 246 bp length were found in the n-STZ- and n-STZ+isradipine-treated groups. More apoptotic cells were observed in the thymus of isradipine-treated, n-STZ-treated and n-STZ+isradipine-treated groups when compared with the non-diabetic control and isradipine+n-STZ-treated groups. In conclusion, we observed that long-term STZ diabetes results in apoptosis in the thymus. We also found that isradipine administered before STZ has protective effects against apoptosis, whereas isradipine alone induces apoptosis.