Danzhi Jiangtang Capsule Mediates NIT-1 Insulinoma Cell Proliferation and Apoptosis by GLP-1/Akt Signaling Pathway.

OBJECTIVE: This study aimed to investigate the effects of Danzhi Jiangtang Capsule (DJC) on the proliferation and apoptosis functions of NIT-1 pancreatic ß-cells exposed to high-glucose load through GLP-1 activated Akt/ FoxO1 signaling pathway. METHODS: Cellular apoptosis of NIT-1 pancreatic ß-cells was induced by culturing in medium with 33.3mmol/L high glucose (HG). Then low-dose DJC (HG +LD), high-dose DJC (HG +HD), high-dose DJC+ GLP-1 inhibition (HG +HD +GI), and high-dose DJC+AKT inhibition (HG +HD+AI) were added, respectively. Cellular proliferation was accessed by cell counting kit (CCK-8) and cellular apoptosis was measured by Annexin V-FITC/PI staining. The protein levels of phosphorylated phosphatidylinositol-3-kinase (p-PI3K), phosphorylated AKT (p-AKT), phosphorylated Forkhead box protein O1 (p-FoxO1), and cleaved caspase-3 were detected by Western blotting. The mRNA expression of pancreatic duodenal homeobox-1 (PDX-1), CyclinD1, Bcl-2, and insulin was tested by Q-PCR. RESULTS: Comparing to HG group, (HG+HD) group showed a significantly increased cellular proliferation. The apoptosis of NIT-1 cells also was obviously reduced, with downregulated cleaved caspase-3 protein level and upregulated PDX-1, CyclinD1, and Bcl-2 mRNA levels (P<0.05). Additionally, (HG+HD) group manifested increased insulin mRNA expression; the protein levels of p-PI3K and p-AKT were markedly increased and p-FoxO1 was decreased. All of the above therapeutic effects by DJC intervention had been reversed by GLP-1 inhibition in (HG+HD+GI) group or AKT inhibition in (HG+HD+AI) group. CONCLUSION: DJC was able to attenuate the toxicity of high-glucose load in NIT-1 pancreatic ß-cells, ascribed to the improvement of cellular proliferation and apoptosis by GLP-1/Akt signaling pathway. This study could supply a new mechanism of DJC effects on type 2 diabetes mellitus (T2DM) treatment.

Detection of melatonin and homocysteine simultaneously in ulcerative colitis.

BACKGROUND: Oxidative stress could be a major contributing factor to the tissue injury that characterize inflammatory bowel disease (IBD). Homocysteine (HCY) could cause oxidative damage to the colon tissue in ulcerative colitis (UC) patients, melatonin (MLT) supplementation could reduce oxidative damage that caused by HCY in vitro and in vivo. In this study, we aimed to determine the levels of plasma HCY and MLT simultaneously in UC patients. METHODS: Collected the clinical data of 112 UC patients and 110 healthy controls (HC). The levels of plasma HCY and MLT were detected by HPLC-FD method. The levels of plasma folate, vitamin B(12) (VitB(12)) were detected by ELISA method. RESULTS: The levels of plasma HCY in UC patients were significantly higher than that in HC (11.27±7.26 µmol/L vs. 8.19±4.81 µmol/L, P=0.000). The levels of plasma MLT in UC patients were significantly lower than that in HC (49.06±31.40 pg/ml vs. 64.28±41.16 pg/ml, P=0.008). The levels of plasma folate and VitB(12) in UC patients were lower than that in HC (7.64±1.95 nmol/L vs. 9.14±1.23 nmol/L, 108.64±32.22 pmol/L vs. 112.64±33.33 pmol/L, P<0.05). The levels of plasma HCY and MLT in UC patients were not correlated with either the erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) or the disease activity, localization and duration of UC (P>0.05). The change of increasing levels of plasma MLT but decreasing levels of plasma HCY was shown in UC patients, however, the association between the levels of plasma MLT and HCY were not statistically significant (P>0.05). CONCLUSIONS: The levels of plasma HCY were increased whereas the levels of plasma MLT were decreased in UC patients.

Effects of melatonin on the expression of iNOS and COX-2 in rat models of colitis.

AIM: To investigate the effects of melatonin (MT) on the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in rat models of colitis. METHODS: Healthy adult Sprague-Dawlay (SD) rats of both sexes, weighing 280+/-30 g, were employed in the present study. The rat models of colitis were induced by either acetic acid or 2,4,6-trinitrobenzene sulfonic acid (TNBS) enemas. The experimental animals were randomly divided into melatonin treatment and model control group that were intracolicly treated daily with melatonin at doses of 2.5, 5.0, 10.0 mg/kg(-1) and equal amount of saline respectively from 24 h following induction of colitis in rats inflicted with acetic acid enema and the seventh day in rats with TNBS to the end of study. A normal control group of rats treated with neither acetic acid nor TNBS but saline enema was also included in the study. On the 28(th) day of the experiment, the rat colon mucosal damage index (CDMI) was calculated, and the colonic prostaglandin E(2) (PGE(2)), nitric oxide (NO), as well as the iNOS and COX-2 expression were also determined biochemically or immunohistochemically. RESULTS: CDMI increased to 2.87+/-0.64 and 3.12+/-1.12 respectively in rats treated with acetic acid and TNBS enema, which was in accordance with the significantly elevated colonic NO and PGE(2) contents, as well as the up-regulated colonic iNOS and COX-2 expression in both of the two rat models of colitis. With treatment by melatonin at the doses of 5.0 and 10.0 mg/kg(-1), CDMI in both models of rat colitis was significantly decreased (P<0.05-0.01), which accorded synchronously and unanimously with the reduced colonic NO and PGE(2) content, as well as the down-regulated expression of colonic iNOS and COX-2. CONCLUSION: Melatonin has a protective effect on colonic injury induced by both acetic acid and TNBS enemas, which is probably via a mechanism of local inhibition of iNOS and COX-2 expression in colonic mucosa.