Supplementation with l -glutathione improves oxidative status and reduces protein nitration in myenteric neurons in the jejunum in diabetic Rattus norvegicus

Key elements determining the intestinal region-specific environment of enteric neurons in type 1 diabetes

Diabetes, as a metabolic disorder, is accompanied with several gastrointestinal (GI) symptoms, like abdominal pain, gastroparesis, diarrhoea or constipation. Serious and complex enteric nervous system damage is confirmed in the background of these diabetic motility complaints. The anatomical length of the GI tract, as well as genetic, developmental, structural and functional differences between its segments contribute to the distinct, intestinal region-specific effects of hyperglycemia. These observations support and highlight the importance of a regional approach in diabetes-related enteric neuropathy. Intestinal large and microvessels are essential for the blood supply of enteric ganglia. Bidirectional morpho-functional linkage exists between enteric neurons and enteroglia, however, there is also a reciprocal communication between enteric neurons and immune cells on which intestinal microbial composition has crucial influence. From this point of view, it is more appropriate to say that enteric neurons partake in multidirectional communication and interact with these key players of the intestinal wall. These interplays may differ from segment to segment, thus, the microenvironment of enteric neurons could be considered strictly regional. The goal of this review is to summarize the main tissue components and molecular factors, such as enteric glia cells, interstitial cells of Cajal, gut vasculature, intestinal epithelium, gut microbiota, immune cells, enteroendocrine cells, pro-oxidants, antioxidant molecules and extracellular matrix, which create and determine a gut region-dependent neuronal environment in diabetes.

The Role of Reduced Glutathione on the Activity of Adenosine Deaminase, Antioxidative System, and Aluminum and Zinc Levels in Experimental Aluminum Toxicity

Aluminum (Al) is one of the most abundant element in the world. But aluminum exposure and accumulation causes serious diseases, related with free radicals. Reduced glutathione (GSH) is a tripeptide with intracellular antioxidant effects. This study aimed to investigate the role of GSH on adenosine deaminase (ADA), antioxidant system, and aluminum and zinc (Zn) levels in acute aluminum toxicity. In this study, Sprague-Dawley rats (n = 32) were used. The rats were divided into four equal groups (n = 8). Group I received 0.5 mL intraperitoneal injection of 0.9% saline solution (NaCI), Group II received single-dose AlCI₃, Group III was given GSH for seven days, and Group IV was given AlCI₃ single dose, and at the same time, 100 mg/kg GSH was given for seven days. At the end of the trial, blood samples were collected by cardiac puncture. Serum total antioxidant status (TAS) and Zn levels were lower in the aluminum-administered group than the control group. In contrast, plasma total oxidant status (TOS) and aluminum concentrations and ADA activity were found higher in the aluminum-administered group than in the control group. Unlike the other groups, group GSH administrated with aluminum was similar to the control group. As a result, GSH administration has a regulatory effect on ADA activity, antioxidant system, and Zn levels in experimental aluminum toxicity. In addition, GSH may reduce the oxidant capacity increased by Al administration and may have a tolerant role on the accumulated serum Al levels. But long-term experimental Al toxicity studies are needed to reach a firm conclusion.

The potential mechanism of Liu-Wei-Di-Huang Pills in treatment of type 2 diabetic mellitus: from gut microbiota to short-chain fatty acids metabolism

BACKGROUND

Type 2 diabetes mellitus (T2DM) has already become a global pandemic. Recently, reports showed its pathogenesis was closely related to a disorder of gut microbiota. In China, the Liu-Wei-Di-Huang Pills (LWDH) have treated T2DM for thousands of years. However, its therapeutic mechanism associated with gut microbiota is worthy of further study.

AIMS

This study aims to investigate the effects of LWDH on T2DM by regulating gut microbiota and short-chain fatty acids (SCFAs) in Goto-Kakizaki (GK) rats.

METHODS

T2DM models were successfully established based on GK rats and administrated with LWDH. The changes in fasting blood glucose (FBG), oral glucose tolerance test (OGTT), and serum insulin (INS) were determined, and the immunohistochemical (IHC) method was used to test INS expression in pancreas. The 16S-ribosomal DNA (16S rDNA) sequencing analysis assessed gut microbiota structural changes; a gas chromatography-mass spectrometer (GC-MS)-based metabolomics method was adopted to detect SCFA levels. The pathological morphology of jejunum was detected by hematoxylin-eosin (H&E) staining, and the expression of GPR43, GPR41, GLP-1, and GLP-1R was evaluated by qRT-PCR and ELISA, respectively.

RESULTS

We observed that GK rats treated with LWDH: (a) has altered the microbial structure and promoted the abundance of bacteria in Firmicutes, including Lactobacillus, Allobaculum, and Ruminococcus_2, (b) increased SCFAs levels involving acetic acid, propionic acid, and butyric acid and (c) alleviated T2DM and jejunum injuries potentially based on SCFAs-GPR43/41-GLP-1 pathway.

CONCLUSION

LWDH could improve T2DM by regulating gut microbiota and SCFAs, and the therapeutic mechanism might be related to the SCFAs-GPR43/41-GLP-1 pathway.

Diabetic Gastroenteropathy: Soothe the Symptoms or Unravel a Cure?

Autonomic neuropathy in patients with diabetes mellitus, and especially complications related to gastrointestinal neuropathy, are often overlooked in the clinic. Diabetic gastroenteropathy affects every segment of the gastrointestinal tract and generates symptoms that may include nausea, early satiety, vomiting, abdominal pain, constipation, and diarrhea. Severe cases can be complicated by weight loss, dehydration, and electrolyte disturbances. The pathophysiology is complex, the diagnostics and treatment options are multidisciplinary, and there is generally a lack of evidence for the treatment options. The aims for this review are first to summarize the pathophysiology and describe possible and expected symptoms and complications.Further, we will try to supply the clinician with a straightforward tool for diagnostics, and then, we shall summarize established treatment options, including diet recommendations, pharmacological and non-pharmacological options. Finally, we will explore the multiple possibilities of novel treatment, looking at medications related to the pathophysiology of neuropathy, other manifestations of autonomic neuropathies, and symptomatic treatment for other gastrointestinal disorders, also including new knowledge of endosurgical and neuromodulatory treatment. The overall goal is to increase awareness and knowledge on this frequent diabetic complication and to provide better tools for diagnosis and treatment. Ultimately, we hope to encourage further research in this field, as there are clear shortcomings in terms of biomarkers, pathophysiology, as well as treatment possibilities. In conclusion, diagnosis and management of diabetic gastroenteropathy are challenging and often require multidisciplinary teams and multimodal therapies. Treatment options are sparse, but new pharmacological, endoscopic, and neuromodulatory techniques have shown promising results in initial studies.

Anticoccidial and Antioxidant Activities of Moringa oleifera Leaf Extract on Murine Intestinal Eimeriosis

BACKGROUND

Coccidiosis is an intestinal disease caused by protozoan parasites of the genus Eimeria and responsible for considerable economic loss in the livestock and poultry industries. Resistance to the current anticoccidial drugs is now a major challenge to efforts to control the disease, and this has stimulated the search for new compounds as alternative treatments. In this context, plant extracts have emerged as an alternative and complementary approach to control coccidiosis. In the present study, an ethanol extract of Moringa oleifera leaves was screened for its anticoccidial activity against Eimeria papillata infection in mice.

METHODS

To this end, albino mice were allocated into three groups: the first group was the non-infected control; the second and third groups were infected with 10³ E. papillata oocysts. Of these, the second group was kept as an infected control; while the third group was gavaged with 100 μl of moringa leaf extract (MLE) at a dose of 400 mg MLE/kg, once daily, for five days.

RESULTS

MLE significantly suppressed oocyst excretion in faeces, and histological study of the jejunum showed a significant decrease in the number of parasitic stages, with significant improvement in the numbers of goblet cells. Furthermore, the expression of MUC2 gene was upregulated in the treated mice compared with infected, which further supports the anticoccidial potential of MLE. Moreover, our study evidenced that MLE reduced oxidative damage by decreasing TBARS and iNOS expression, and increasing the GSH and GPX levels. Also, treatment with MLE promoted the expression of Bcl-2 and ultimately, inhibited the apoptosis of host cells in the treated mice.

CONCLUSION

Our data indicate that MLE has anticoccidial, anti-oxidant and anti-apoptotic activities in mice infected with Eimeria papillata.

Quercetin increases bioavailability of nitric oxide in the jejunum of euglycemic and diabetic rats and induces neuronal plasticity in the myenteric plexus

Considering the antioxidant, neuroprotective, inflammatory and nitric oxide modulatory actions of quercetin, the aim of this study was to test the effect of quercetin administration in drinking water (40 mg/day/rat) on neuronal nitric oxide synthase (nNOS), vasoactive intestinal peptide (VIP), overall population of myenteric neurons (HuC/D) and nitric oxide (NO) levels in the jejunal samples from diabetic rats. Male Wistar rats were distributed into four groups (8 rats per group): euglycemic (E), euglycemic administered with quercetin (E+Q), diabetic (D) and diabetic administered with quercetin (D+Q). Rats were induced to diabetes with streptozotocin (35mg/kg/iv) and, after 120 days, the proximal jejunum were collected and processed for immunohistochemical (VIP, nNOS and HuC/D) and chemiluminescence (quantification of tissue NO levels) techniques. Diabetes mellitus reduced the number of nNOS-IR (immunoreactive) (p <0.05) and HuC/D-IR (p <0.001) neurons, however, promoted an increased morphometric area of nNOS-IR neurons (p <0.001) and VIP-IR varicosities (p <0.05). In D+Q group, neuroplasticity effects were observed on HuC/D-IR neurons, accompanied by a reduction of cell body area of neurons nNOS- and VIP-IR varicosities (p <0.05). The NO levels were increased in the E+Q (p <0.05) and D+Q group (p <0.001) compared to the control group. In conclusion, the results showed that quercetin supplementation increased the bioavailability of NO in the jejunum in euglycemic and mitigate the effects of diabetes on nNOS-IR neurons and VIP-IR varicosities in the myenteric plexus of diabetic rats.