Exploring the antioxidant and anti-inflammatory therapeutic potential of homoplantaginin, a flavonoid glycoside, in ameliorating gestational diabetes mellitus: in vivo study.

BackgroundGestational diabetes mellitus (GDM) is a disorder of glucose metabolism that occurs or is found for the first time during pregnancy. GDM is very harmful and urgently needs drug treatment to improve pregnancy outcome. PPARδ is involved in a variety of biological processes related to glycolipid metabolism in the body, suggesting that it may be closely related to insulin resistance and impaired glucose tolerance. The role of PPARδ agonist GW501516 in gestational diabetes has not been studied.MethodsFirstly, the rat model of GDM was established. Then, fasting blood-glucose (FGB), fasting insulin (FINS), HOMA-islet resistance index (HOMA-IR) and insulin sensitivity index (ISI) of GDM rats treated with GW501516 were measured on day 3, day 10 and day 17. Glucose tolerance test was performed on the 20th day of gestation to measure glucose tolerance in rats. The expression of PPARδ and Angptl8 in islet tissues of rats was detected by Western blot and immunohistochemistry (IHC). Histopathological changes of islet were detected by HE stain; apoptosis rate of islet cells was detected by Tunel; and expression of apoptosis-related proteins in the cells was detected by Western blot. The biochemical kits were used to detect the expression of lipid metabolism-related factors in blood of GDM rats after the PPARδ agonist GW501516 treatment. Finally, the expression of SREBP-1c and GLUT2 in islet tissues was detected by RT-qPCR and IHC.ResultsThe PPARδ agonist GW501516 decreased the expression of FGB, FINS and HOMA-IR in GDM rats, and we found that GW501516 decreased ISI in GDM rats. GW501516 increased glucose tolerance in GDM rats too. In GDM rats, the expression of PPARδ in islet decreased and the expression of Angptl8 increased, which was reversed by GW501516. In addition, we also found that GW501516 can improve the damaged islet tissue of GDM rats, reduce the apoptosis rate of islet cells and inhibit the expression of lipid metabolism-related factors in the blood. Finally, we found that GW501516 inhibited the expression of SREBP-1c and promoted the expression of GLUT2 in the islet tissue.ConclusionThe PPARδ agonist GW501516 could improve the blood glucose level, damaged islet tissue and increase the insulin content in the rats with GDM, possibly by regulating the SREBP-1c/GLUT2 pathway. Our study provided a new basis for clinical treatment of GDM in pregnant women with PPARδ agonist GW501516.

Proinflammation in maternal and fetal livers and circulating miR-122 dysregulation in a GDM rat model induced by intrauterine programming

Objective This study aimed to explore the possible mechanism of adiponectin on the insulin signaling in streptozotocin (STZ)-induced gestational diabetes mellitus (GDM) rats. Methods The GDM rats were induced by injection of 40mg/kg STZ, and then orally treated with adiponectin (5, 10, 20mg/kg) every day from gestation day (GD)7 to GD20. The body weight and fasting blood glucose (FBG) were observed every 3 days from GD9 to GD18. Meanwhile, the insulin tolerance test (ITT), homeostasis model assessment insulin resistance (HOMA-IR), and adiponectin expression were observed in rats. Moreover, the insulin signaling-related factors, sex hormone-binding globulin (SHBG), PPAR-α, phospho-AMPK alpha, glucose transporter-3 (GLUT3), and phospho-insulin receptor substrate-1 (p-IRS1) in placental tissues were measured in rats. In vitro, HTR-8-Svneo cells were induced by 30 mM glucose and then treated with adiponectin (50, 100, 200 ng/mL) to observe the changes in cell viability, SHBG expression, and the insulin signaling-related factors. Moreover, silencing or overexpression of SHBG was achieved via transfection with siRNA or pEX-4 SHBG, respectively. The effects of SHBG on the insulin signaling-related factors were observed in cells. Results Adiponectin treatment significantly improved the STZ-induced decrease in body weight, increase in the FBG, ITT, and HOMA-IR with increasing doses. Specifically, adiponectin treatment upregulated the SHBG expression and the insulin signaling-related factors (PPAR-α, p-AMPK, GLUT3, and p-IRS1) in the placental tissues of GDM rats with increasing doses. In line with the results of animal experiments, adiponectin treatment alleviated the high glucose-induced decrease in cell viability, SHBG expression, and the levels of GLUT3 and p-IRS1 in HTR-8-Svneo cells with increasing doses. Moreover, the levels of GLUT3 and p-IRS1 were regulated by the SHBG expression. SHBG silencing weakened the effect of adiponectin in improving the levels of GLUT3 and p-IRS in the high-glucose-induced cells. Conclusion The study showed that adiponectin upregulated the SHBG expression and improved the insulin signaling in STZ-induced GDM rats, as well as adiponectin upregulated the insulin signaling-related factors via SHBG in high-glucose-induced trophoblast cells. This study suggests that adiponectin may be a potential therapeutic target in GDM.

To study the roles of advanced glycation end products and its receptor on fetal brain injury of gestational diabetes mellitus (GDM) rats. Twenty one adult pregnant Wistar rats were administered streptozotocin (STZ) intraperitoneally to induce GDM rats model. The fourteen pregnant rats were divided into two groups according to the fasting glucose on the 3(rd) day of pregnancy:severe GDM group with the fasting glucose > 16.7 mmol/L and mild GDM group with the fasting glucose between 6.7 - 16.7 mmol/L. Another seven pregnant rats were chosen as the severe GDM and intervention with micronutrient group, receiving gavage with micronutrient during the whole pregnancy. Five control rats received the same volume of citric acid buffer. All the pregnant rats were tested fasting glucose from the tail vein and their weight on the pregnant day 3, 13 and 19. Maternal serum levels of AGE were measured by ELISA and RAGE levels in the embryonic brain tissues were tested by immunohistochemistry. (1) There was no statistically significant difference of pre-pregnancy fasting glucose level among all groups (P > 0.05). The fasting glucose levels on the 3(rd) day and the mean fasting glucouse level of pregnancy in the severe GDM group and the severe GDM and intervention with micronutrient group were higher than those of the control group (P < 0.05). And there was no significant difference between the severe GDM group and the severe GDM and intervention with micronutrient group (P > 0.05). (2) The serum AGE levels in the severe GDM group and the mild GDM group were (1037 ± 38) ng/L and (880 ± 34) ng/L respectively, with no significant difference (P > 0.05). The serum AGE levels in the control group and the severe GDM and intervention with micronutrient group were (857 ± 32) ng/L and (988 ± 37) ng/L, and the difference was statistically significant (P < 0.05). The serum AGE levels in the severe GDM and intervention with micronutrient group and in the mild GDM group had no significant difference (P > 0.05). (3) The serum AGE levels in the severe GDM group, mild GDM group and the control group were positively associated with the mean glucose level of pregnancy (r = 0.603, P < 0.05) and the grlucose on the 3(rd) day of pregnancy (r = 0.704, P < 0.05). (4) The fetal brain nerve cell number and morphology in the control group were normal. While in the mild GDM group fetal brain nerve cells decreased, the proliferation and swelling of glial cells were seen. In the severe GDM group and the severe GDM and intervention with micronutrient group, the fetal brain cells furtherly reduced, and large vacuole around the cells, deformation and debris of the cells were seen. Glial scar formation was visible in some fetal brain tissues. There was a few RAGE expression in the control fetal brain tissues. In the mild GDM group and the severe GDM group, RAGE expression increased significantly. And the RAGE expression intensity in the severe GDM and intervention with micronutrient group was between the severe and the mild GDM groups. (1) Abnormal fetal brain development of GDM rats was associated with the increase of maternal serum AGE and the enhancement of RAGE expression in fetal brain tissues, which suggested that AGE/RAGE pathway may play an important role in the fetal brain injury of GDM rats. (2) Micronutrients can reduce the brain damage of GDM fetuses.

The roles of gut microbiota and metabolomics in women with gestational diabetes mellitus (GDM) are not well understood. This study investigated the gut metabolomic profiling of GDM rats and GDM rats treated with probiotic supplements. Associations between gut metabolites and microbiota were also studied in GDM rats. Liquid chromatography–mass spectrometry was used to detect gut metabolites in GDM rats and GDM rats treated with probiotic supplements of 0.5 g (low-dose group) or 1 g (high-dose group) for 15 days. Each gram of probiotic supplement contained 5 × 107 colony-forming units (CFU) of Lactobacillus rhamnosus LGG and 1 × 108 CFU of Bifidobacterium animalis subspecies lactis Bb12. The association between gut metabolites and microbiota in GDM rats was investigated using Spearman’s correlation. Finally, 10 rats in the normal pregnant group, eight rats in the GDM model group, eight GDM rats in the low-dose probiotics group, and nine GDM rats in the high-dose probiotics group were further studied. Serum parameters and pancreatic and colon histology were significantly changed in GDM rats, and these were restored using probiotic supplements. In total, 999 gut metabolites were detected in the feces, and GDM rats were distinguished from normal rats. The levels of 44 metabolites were increased in GDM rats, and they were alleviated using probiotic supplements. Changes in metabolites in GDM rats were associated with amino acids and bile acids metabolism signaling pathways. Furthermore, changes in metabolites after probiotic supplementation were associated with porphyrin and chlorophyll metabolism pathways. We found that the Allobaculum genus displayed strong positive correlations, whereas the Bryobacter and Gemmatimonas genera displayed strong negative correlations with metabolisms of amino acids and bile acids in GDM rats. The Lactobacillus and Bifidobacterium genera were positively correlated with gut metabolites. Overall, our results showed that metabolism signaling pathways of amino acids and bile acids are associated with the development of GDM. Probiotic supplements alleviate the pathology of GDM through the metabolism pathways of amino acids, bile acids, porphyrin, and chlorophyll.

To reveal the effects of Oldenlandia diffusa (OD) on relieving the progression and development of gestational diabetes mellitus (GDM), and explore the underlying mechanism. A rat model of GDM was established by streptozotocin injection. The effects of OD on GDM rats were evaluated by measuring the levels of fasting blood glucose (FBG), insulin, and hemoglobin A1c (HbA1c), and exposing to oral glucose tolerance test (OGTT) and histological evaluation of the pancreas. The levels of insulin and inflammation response-related factors (tumor necrosis factor [TNF]-α, Interleukin [IL]-6 and IL-1β) were evaluated by enzyme-linked immunosorbent assay (ELISA). Additionally, immunoblot assay was performed to investigate the effects of OD on the nuclear factor-κb (NF-κB) pathway and 5' adenosine monophosphate-activated protein kinase (AMPK) pathway. OD decreased blood glucose level, pancreatic tissue damage, and insulin secretion in GDM rats. OD also reduced serum inflammatory levels (TNF-α, IL-6, and IL-1β) in GDM rats. Mechanically, OD could inhibit NF-κB pathway and activate AMPK pathway in the pancreatic tissue of GDM rats. OD affected glucose metabolism and inflammation level in rats with streptozotocin-induced GDM, and the underlying mechanism was through AMPK pathway. OD might serve as a promising and potential drug for the treatment of GDM.

Gestational diabetes mellitus is a type of diabetes that arises during pregnancy. Around 15–25% of pregnancies are affected by gestational diabetes mellitus, which involves hyperglycemia, insulin resistance, and abnormal fetal development. The present work was conducted to reveal the therapeutic potentials of dictamnine against streptozotocin-induced gestational diabetes mellitus in rats. To induce gestational diabetes mellitus, pregnant rats were administered the streptozotocin, and subsequently, the gestational diabetes mellitus rats were given dictamnine for 14 days. Following the end of treatments, the body weight, blood glucose, and fetus and placental weights were measured. The concentrations of biochemical markers, including fasting insulin, HbA1c, and hepatic glycogen, were analyzed. The lipid profiles, antioxidant levels, apoptotic proteins, and inflammatory cytokine levels were measured using the test kits. A histopathological investigation was conducted on the pancreatic tissues obtained from the experimental rats. Dictamnine treatment at concentrations of 15 and 30 mg/kg successfully reduced glucose levels, increased body weight, and regulated insulin and other biochemical marker levels in rats with gestational diabetes mellitus. The treatment of dictamnine resulted in an increase in the antioxidant levels, successfully lowered the lipid markers in the rats with gestational diabetes mellitus. The treatment with dictamnine also reduced the inflammatory cytokines, apoptotic proteins, and other molecular markers in the gestational diabetes mellitus rats. The histological study of pancreatic tissues likewise confirmed the therapeutic capabilities of dictamnine. The results of the current study emphasize that dictamnine has a positive effect on reducing gestational diabetes mellitus in rats.Graphical

Eupatilin mitigates Gestational diabetes in streptozotocin-induced diabetic pregnant rats through the Regulation of inflammation and oxidative stress

Gestational diabetes mellitus (GDM) is a serious life-threatening disease that affects the mother and fetus. However, the pathogenesis of GDM is still unclear. microRNAs (miRs) play vital roles in the regulation of various cell functions. The present study aimed to investigate the effects of miR-875-5p and thioredoxin reductase 1 cytoplasmic (TXNRD1) in GDM rats and analyze the associated underlying mechanism. A GDM rat model was induced using an intraperitoneal injection of streptozotocin. miR-875-5p knockdown plasmids or TXNRD1 knockdown plasmids were injected into the rats via the caudal vein. miR-875-5p and TXNRD1 expression in the serum were detected using reverse transcription-quantitative PCR (RT-qPCR) or western blot (WB) analyses. The fasting blood-glucose (FBG), fasting serum insulin, triglyceride and high density lipoprotein levels were detected by specific commercial kits. The inflammatory response and the induction of oxidative stress were analyzed by assessing the expression of associated markers via WB, RT-qPCR or commercial kits. The pancreatic and placental injuries were detected by hematoxylin and eosin staining. The results indicated that miR-875-5p expression levels were downregulated, whereas TXNRD1 levels were upregulated in GDM rats compared with normal pregnancy rats. miR-875-5p significantly regulated TXNRD1 expression in GDM rats. miR-875-5p silencing notably reduced FBG and insulin resistance, which was accompanied by reduced expression levels of blood lipid and pro-inflammatory markers as well as reduced oxidative stress. However, the effects of miR-875-5p could be reversed by TXNRD1 silencing. Therefore, the present study indicated that miR-875-5p regulated IR and inflammation by targeting TXNRD1 in GDM rats. miR-875-5p and TXNRD1 may be considered as potential targets for treating GDM.

Gestational diabetes mellitus (GDM), a severe pregnancy disorder, is a temporary form of diabetes that occurs during gestation. Astragaloside IV (AS IV), a natural and effective composition of Astragalus membranaceus, shows pharmacological effects against diabetes. On the contrary, the effects of AS IV on GDM development are still not clear. This study aims to investigate the role of AS IV in alleviating GDM in rats and determine whether AS IV exerts its anti-GDM properties through the regulation of gut microbiota and metabolite modulation. There were six pregnant SD rats in each of the four groups. First, the GDM model was induced by the streptozotocin (STZ, 45mg/kg) injection on gestational days (GDs) 1-4, and AS IV intervention (10mg/kg/d) was administered from 6days before pregnancy until delivery. The measurements of relevant indicators pertaining to GDM symptoms and reproductive outcomes, along with the 16S rRNA sequencing data and LC-MS-based metabolomic profiles, were assessed across all groups. After the 25-day intervention, the GDM model + AS IV group showed significantly decreased fasting blood glucose levels (p = 0.0003), mean insulin levels (p = 0.0001), and insulin resistance index (p = 0.0001). AS IV treatment also decreased the malformation rate (p = 0.0373) and increased the average fetal weight (p = 0.0020) of GDM rats. Compared to the control rats, GDM rats showed a significantly higher abundance of Blautia and Anaerobiospirillum. However, the dramatically elevated abundance of these microorganisms was markedly decreased by AS IV treatment. In contrast, compared to GDM rats without treatment, GDM rats treated with AS IV showed a significantly higher abundance of bacteria (p < 0.05), such as Methanobrevibacter, Dubosiella, and Romboutsia, which are beneficial to the rats. Additionally, we observed dramatically elevated production of metabolites, such as N-acetyl-l-leucine and lithocholic acid, after AS IV treatment through metabolomics analysis (p < 0.05). Furthermore, significant associations between most genera of gut bacteria and the altered levels of the metabolites connected to gut microbiota were also discovered. Our study demonstrated that AS IV could be an effective nutritional intervention strategy for targeting gut microbiota and metabolome profiles in GDM and provided experimental evidence supporting the use of AS IV to treat GDM.

We previously reported that glycation induces insulin resistance in the hearts of newborn pups from a gestational diabetes mellitus (GDM) rat model. Administration of n-3 unsaturated fatty acids suppressed glycation and improved signaling in GDM rat pups. In this study, we investigated their effects on cranial neurons using the GDM rat model and PC12 cells derived from rat adrenal pheochromocytomas. Additionally, we examined whether n-3 and n-7 unsaturated fatty acids (cis-palmitoleic acid [CPA] and trans-palmitoleic acid [TPA]) ameliorate the detrimental effects of high glucose exposure on rats. In the neonatal cerebrum of GDM rats, increased levels of advanced glycation end products (AGEs) inhibited Akt phosphorylation; however, CPA and TPA intake during pregnancy ameliorated these abnormalities. Furthermore, exposure to high-glucose-induced apoptosis in PC12 cells compared to the cells cultured in control glucose. PC12 cells exposed to high-glucose with fatty acids exhibited reduced AGE production and apoptosis induction compared to the high-glucose group. These findings suggest that a hyperglycemic environment during pregnancy promotes AGE formation in brain neuronal proteins and induces apoptosis. Both TPA and CPA mitigated these abnormalities; however, CPA is cytotoxic, highlighting its safety in pregnant women.

A selenium (Se)-containing polysaccharide, lotus leaf selenium (Se)-polysaccharide (LLP), was isolated from a lotus leaf. The effects of LLP on antioxidant enzyme activities and insulin resistance in pregnant rats with gestational diabetes mellitus (GDM) were investigated. LLP administered orally at two doses (50 and 100mg/kg) could significantly reverse the weight loss of pregnant rats before the delivery, fetal rats, and placentas in GDM rats (P<0.05). Furthermore, LLP treatment induced a decrease of fasting blood glucose (FBG) and fasting blood insulin (FINS) levels in GDM rats, but an increase of hepatic glycogen content, when compared with those in GDM rats (P<0.05). Also, oral administrations of LLP markedly improved the lipid profile of GDM rats, as evidenced by a reduction of total cholesterol (TC), triglyceride (TG), and low-density lipoprotein (LDL) cholesterol levels except for the high-density lipoprotein (HDL) cholesterol level. Additionally, antioxidant enzyme levels, such as superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx), and glutathione (GSH), in liver tissues of the GDM group were lower than those of the other groups, and following treatment of LLP, these indexes in liver tissues were equivalent to those of the control group (P>0.05). All the data indicated that LLP may be a promising drug candidate or a healthcare food for GDM therapy or protection.

Hypertensive (HTN) disorders of pregnancy increase risks for gestational diabetes mellitus (GDM) in pregnant women. GDM is characterized by hyperglycemia and β-cell dysfunction associated with increased inflammatory cytokines, oxidative stress, and activated CD4+ T cells. Streptozotocin (STZ) is used in nonpregnant rats to induce β-cell destruction causing features of diabetes. However, STZ is not ideal for pregnancy and leads to unsuccessful pregnancy outcomes, therefore other ways to establish animal models of GDM must be pursued. Previously, we showed CD4+T cells from a rat model of preeclampsia causes HTN and mitochondrial (mt) dysfunction/ROS compared to normal pregnant (NP) rats. Therefore, we hypothesize CD4+ T cells from a diabetic rat model could cause mt dysfunction/ROS and pancreatic β-islet cell destruction and lead to increased glucose and HTN during pregnancy. To examine our hypothesis, we adoptively transferred CD4+ T cells from STZ Dahl diabetic rats into pregnant Sprague Dawley (SD) rats and measured GDM features. Circulating CD4+ T cells were isolated from STZ induced diabetic Dahl virgin female rats and injected into pregnant SD rats on gestational day (GD) 12. On GD19, blood pressure (MAP) and tissues were collected and glucose levels were measured after 2h fasting in STZ CD4+ T cell recipients (GDM) and NP controls. Mt respiration and mtROS was measured in isolated mitochondria. On GD19, MAP increased to 105±0.5 mmHg (n=4, p&lt;0.05) in GMD pregnant rats compared to control NP rats 91±2.1 mmHg (n=3). Blood glucose levels were elevated in GDM rats (139 ± 7 mg/dl, n=4, p&lt;0.05) compared to NP controls (94 ± 1 mg/dl, n=3). Placental state 3 (26.4±5.9 vs 53.9±1.7 pmol/sec/mg, p&lt;0.05) respiration rates, indicative of ATP production, was reduced in GDM rats (n=4) compared to NP controls (n=3). Placental mtROS was significantly increased in GDM rats (190 ± 27.1 % gated, n=3, p&lt;0.05) compared to NP rats (100 ± 2.7 % gated, n=3). Collectively, the data indicate adoptive transfer of STZ CD4+ T cells causes increased circulating glucose, placental mt dysfunction and mtROS and HTN during pregnancy. These data demonstrate the importance of CD4+T cells in mechanisms causing the pathophysiology of GDM, and also introduces a potential novel animal model of GDM.

Sex-dependent changes in lipid metabolism, PPAR pathways and microRNAs that target PPARs in the fetal liver of rats with gestational diabetes

To investigate the role of micro-ribonucleic acid-29b (miR-29b) in rats with gestational diabetes mellitus (GDM) through the phosphatidylinositol 3-kinase (PI3K)/serine/threonine kinase (Akt) signal and its mechanism by establishing rat models of GDM. Rat models of GDM were constructed, and then the expression levels of miR-29b, total PI3K, phosphorylated PI3K (p-PI3K), total Akt and phosphorylated Akt (p-Akt) in the model group and control group were measured via Reverse Transcription-Polymerase Chain Reaction (RT-PCR) and Western blotting assays, and the association between miR-29b expression and total PI3K expression was analyzed. In addition, miR-29b mimics and inhibitors were used to further explore the regulatory pathway, and the influences of miR-29b mimics and inhibitors on PI3K and Akt phosphorylation in GDM rats, characteristic indicators of oxidative stress such as superoxide dismutase (SOD), catalase (CAT) and malondialdehyde (MDA) in liver tissues of GDM rats, and fasting blood glucose in GDM rats were studied. Compared with those in the control group, miR-29b expression was lowered in rat models of GDM, while PI3K/Akt signal expression was increased. In rats with GDM, miR-29b expression was prominently negatively correlated with total PI3K expression (r=-0.777, p=0.007, p<0.01). MiR-29b mimics could reduce PI3K and Akt phosphorylation, increase SOD and CAT expression levels and decrease MDA content (p<0.05). Moreover, miR-29b mimics significantly lowered the blood glucose level in rats with GDM (p<0.05). MiR-29b mimics can alleviate oxidative stress and reduce blood glucose by inhibiting the PI3K/Akt signal transduction.