Effects of Thymoquinone on STZ-induced Diabetic Nephropathy: An Immunohistochemical Study

The role of high mobility group box-1 on the development of diabetes complications: A plausible pharmacological target

BACKGROUND

Diabetes mellitus has emerged as a pressing global concern, with a notable increase in recent years. Despite advancements in treatment, existing medications struggle to halt the progression of diabetes and its associated complications. Increasing evidence underscores inflammation as a significant driver in the onset of diabetes mellitus. Therefore, perspectives on new therapies must consider shifting focus from metabolic stress to inflammation. High mobility group box (HMGB-1), a nuclear protein regulating gene expression, gained attention as an endogenous danger signal capable of sparking inflammatory responses upon release into the extracellular environment in the late 1990s.

PURPOSE

Given the parallels between inflammatory responses and type 2 diabetes (T2D) development, this review paper explores HMGB-1's potential involvement in onset and progression of diabetes complications. Specifically, we will review and update the understanding of HMGB-1 and its inflammatory pathways in insulin resistance, diabetic nephropathy, diabetic neuropathy, and diabetic retinopathy.

CONCLUSIONS

HMGB-1 and its receptors i.e. receptor for advanced glycation end-products (RAGE) and toll-like receptors (TLRs) present promising targets for antidiabetic interventions. Ongoing and future projects in this realm hold promise for innovative approaches targeting HMGB-1-mediated inflammation to ameliorate diabetes and its complications.

Roles of Matrix Metalloproteinases and Their Natural Inhibitors in Metabolism: Insights into Health and Disease

Matrix metalloproteinases (MMPs) are a family of zinc-activated peptidases that can be classified into six major classes, including gelatinases, collagenases, stromelysins, matrilysins, membrane type metalloproteinases, and other unclassified MMPs. The activity of MMPs is regulated by natural inhibitors called tissue inhibitors of metalloproteinases (TIMPs). MMPs are involved in a wide range of biological processes, both in normal physiological conditions and pathological states. While some of these functions occur during development, others occur in postnatal life. Although the roles of several MMPs have been extensively studied in cancer and inflammation, their function in metabolism and metabolic diseases have only recently begun to be uncovered, particularly over the last two decades. This review aims to summarize the current knowledge regarding the metabolic roles of metalloproteinases in physiology, with a strong emphasis on adipose tissue homeostasis, and to highlight the consequences of impaired or exacerbated MMP actions in the development of metabolic disorders such as obesity, fatty liver disease, and type 2 diabetes.

Effect of Nigella sativa and its bioactive compound on type 2 epithelial to mesenchymal transition: a systematic review

BACKGROUND

Nigella sativa or commonly known as black seed or black cumin is one of the most ubiquitous complementary medicine. Epithelial to mesenchymal transition (EMT) of type 2 is defined by the balance between wound healing and tissue fibrosis, which is dependent to the state of inflammation. This systematic review is conducted to provide an overview regarding the reported effect of Nigella sativa and its bioactive compound on the type 2 EMT.

METHODS

A search was done in EBSCOHOST, OVID and SCOPUS database to obtain potentially relevant articles that were published between 1823 and August 2019. This review includes studies that focus on the effect of Nigella sativa and its bioactive compound on the events related to type 2 EMT.

RESULTS

A total of 1393 research articles were found to be potentially related to the effect of Nigella sativa and its bioactive compound, thymoquinone on Type 2 EMT. After screening was done, 22 research articles met inclusion criteria and were included in this review. Majority of the studies, reported better wound healing rate or significant prevention of tissue inflammation and organ fibrosis following Nigella sativa or thymoquinone treatments. In terms of wound healing, studies included reported progression of EMT related pathological changes after treatment with Nigella sativa or thymoquinone. Alternatively, in terms of fibrosis and inflammation, studies included reported reversal of pathological changes related to EMT after treatment with Nigella sativa or thymoquinone.

CONCLUSION

Through this review, Nigella sativa and thymoquinone have been associated with events in Type 2 EMT. They have been shown to promote wound healing, attenuate tissue inflammation, and prevent organ fibrosis via regulation of the EMT process.

Nigella sativa stimulates insulin secretion from isolated rat islets and inhibits the digestion and absorption of (CH2O)n in the gut

Nigella sativa seeds are traditionally reputed as possessing anti-diabetic properties. As a result, we aim to explore the mechanism of its anti-hyperglycemic activity. The present study uses various experimental designs including gastrointestinal (GI) motility, intestinal disaccharidase activity and inhibition of carbohydrate digestion and absorption in the gut. The animals used as type 2 diabetic models were induced with streptozotocin to make them as such. Oral glucose tolerance test was performed to confirm that the animals were indeed diabetic. The extract reduced postprandial glucose, suggesting it interfered with glucose absorption in the gut. It also improved glucose (2.5g/kg, b/w) tolerance in rats. Furthermore, treatment with N. sativa produced a significant improvement in GI motility, while reduced disaccharidase enzyme activity in fasted rats. The extract produced a similar effect within an acute oral sucrose (2.5g/kg, b/w) load assay. Following sucrose administration, a substantial amount of unabsorbed sucrose was found in six different parts of the GI tract. This indicates that N. sativa has the potentiality to liberate GI content and reduce or delay glucose absorption. A potential hypoglycemic activity of the extract found in insulin release assay, where the extract significantly improved insulin secretion from isolated rat islets. These concluded present findings give rise to the implication that N. sativa seeds are generating postprandial anti-hyperglycemic activity within type 2 diabetic animal models via reducing or delaying carbohydrate digestion and absorption in the gut as well as improving insulin secretion in response to the plasma glucose.

Impact of thymoquinone on cyclosporine A pharmacokinetics and toxicity in rodents

Objectives

Cyclosporine A (CsA) is an immunosupprsant drug used to prevent graft rejection and in the treatment of several autoimmune diseases. Thyomquinone (TQ), a bioactive component of Nigella sativa, has strong antioxidant properties and has been used in prevention of many toxicities, hence its protective effect and pharmacokinetic interactions with CsA was investigated in this study.

Methods

For bioavailability study, the rats were divided into four groups: TQ (PO, 10 mg/kg) was given alone for 7 days, then TQ plus CsA for another 5 days, CsA was given by two routes (po) and (IP) in a dose of 10 mg/kg 1 h after administration of TQ. Blood samples were taken at the 12th day at specified times, CsA level was determined by immune assays. The protective effect of TQ was studied. Blood samples for lab investigations and histopathology were taken at the 28th day.

Key findings

Thyomquinone reduced the bioavailability of oral CsA by around 32% (P > 0.05). However, bioavailability of IP administered CsA was not affected. Chronic administration of CsA increased concentrations of fasting glucose and Cystatin C and produced marked s kidney alteration of parenchyma which was reversed by concomitant administration of TQ.

Conclusions

A potential drug interaction between TQ and CsA, which may reduced its oral bioavailability. Independently TQ caused significant attenuation of CsA induced renal toxicity and diabetogenic effect.

An Overview on Renoprotective Effects of Thymoquinone

Background

Kidneys as vital organs remove waste material from blood. Additionally, they may also have a role in the electrolyte balance, regulation of blood pressure, and red blood cell genesis. Kidney diseases may be caused by several factors such as ischemia/reperfusion injury, diabetes, and nephrotoxic agents. Oxidative stress and inflammation are involved in the pathogenesis and progression of kidney diseases. Traditionally, natural antioxidants are used for treatment of renal failure in various countries.

Summary

People usually select natural antioxidants since they have an opinion that herbal medicine has not any important side effects. Nigella sativa is a flavoring herb that is widely used as a condiment and as a remedy for many disorders. Thymoquinone (TQ), the most important component of black seeds, mainly oil, is considered as an active agent responsible for a lot of the seed's useful effects. This review describes the protective roles and related mechanisms of TQ against renal disorders. The search terms, including TQ, antioxidant, renal ischemia-reperfusion, diabetic nephropathy, and nephrotoxic agent were searched in scientific databases. TQ showed anti-inflammatory and antioxidant properties in animal and in vitro models of several renal diseases caused by inflammation and oxidative stress.

Key Messages

Experimental studies have shown beneficial effects of TQ against renal diseases; however, well-designed clinical trials in humans are required to confirm these effects.

Pharmacotherapy with Thymoquinone Improved Pancreatic β-Cell Integrity and Functional Activity, Enhanced Islets Revascularization, and Alleviated Metabolic and Hepato-Renal Disturbances in Streptozotocin-Induced Diabetes in Rats

Aims: This study is aimed at evaluating the antidiabetic effects of thymoquinone (TQ) on streptozotocin (STZ)-induced diabetes in rats, and exploring the possible underlying mechanisms. Methods: Diabetes was induced in adult male Wistar rats by intraperitoneal injection of freshly prepared STZ (65 mg/kg). After disease induction, 42 rats were equally assigned to: controls, STZ-diabetic group, and STZ-diabetic group treated with oral TQ (35 mg/kg/day) for 5 weeks. Fasting blood glucose levels were determined weekly, and the animals were euthanized at day 38 post-STZ injection. Blood samples were assessed for glucose-insulin homeostasis parameters (plasma glucose, glycated hemoglobin, serum insulin, homeostatic model assessment of insulin resistance, and insulin sensitivity index) and lipid profile. Resected pancreases were subjected to histological examination and immunohistochemical or enzyme-linked immunosorbent assay assessment to determine the pancreatic expression of insulin sensitizing β-cells, anti-apoptotic protein “survivin,” apoptosis-inducer “caspase-3,” prototypic angiogenic factors (vascular endothelial growth factor [VEGF] and endothelial cluster of differentiation 31 [CD31]), pro- and anti-inflammatory cytokines (interleukin-1beta [IL-1β] and interleukin-10 [IL-10], respectively), thiobarbituric acid reactive substances (TBARS), total glutathione (GSH), and superoxide dismutase (SOD). The hepato-renal statuses were assessed biochemically and histologically. Results: Therapy with TQ markedly improved the integrity of pancreatic islets, glucose-insulin homeostasis-related parameters, lipid profile parameters, and hepato-renal functional and histomorphological statuses that collectively were severely deteriorated in untreated diabetic group. Mechanistically, TQ therapy efficiently increased insulin producing β-cells, upregulated survivin, VEGF, CD31, IL-10, GSH and SOD, and downregulated caspase-3, IL-1β, and TBARSs in the pancreatic tissues of STZ-diabetic rats. Conclusions: These findings prove the anti-diabetic potential of TQ and its efficacy in regenerating pancreatic β-cells and ameliorating pancreatic inflammation and oxidative stress, and highlight its novelty in repressing apoptosis of β-cells and enhancing islet revascularization in STZ-diabetic rats. Further studies are required to support these findings and realize their possible clinical significance.

The Ameliorative Effect of Pectin-Insulin Patch On Renal Injury in Streptozotocin-Induced Diabetic Rats

BACKGROUND/AIMS

Renal damage and dysfunction is attributed to sustained hyperglycaemia in overt diabetes. Subcutaneous insulin injections are beneficial in delaying the progression of renal dysfunction and damage in diabetics. However, the current mode of administration is associated with severe undesirable effects. In this study, we evaluated the ameliorative effects of pectin-insulin dermal patches on renal dysfunction in diabetes.

METHODS

Pectin-insulin patches (20.0, 40.8 and 82.9 µg/kg) were applied on the skin of streptozotocin-induced diabetic rats, thrice daily for 5 weeks. Blood glucose concentration, blood pressure and urine output volume were recorded on week 5 after which the animals were sacrificed after which the kidneys and plasma were collected. Kidney nephrin expression and urinary nephrin concentration, albumin excretion rate (AER), creatinine clearance (CC) and albumin creatinine ratio (ACR) were assessed.

RESULTS

Patch application resulted in reduced blood glucose concentration and blood pressure. Furthermore, pectin-insulin patch treatment resulted in increased kidney nephrin expression and reduced urinary nephrin concentration. AER, CC ACR were also reduced post patch application.

CONCLUSIONS

The application of pectin-insulin patch limited diabetes associated kidney damaged and improved kidney function. These observations suggest that pectin-insulin patches may ameliorate kidney dysfunction that is associated with chronic subcutaneous insulin administration.

GC-MS-based Metabolomic Profiling of Thymoquinone in Streptozotocin-induced Diabetic Nephropathy in Rats

Diabetic nephropathy is a common complication of diabetes mellitus and one of the major etiologies of end-stage renal disease. Specific therapeutic interventions are necessary to treat such complications. The present study was designed to investigate the metabolomic changes induced by thymoquinone for the treatment of diabetic nephropathy, using a rodent model. Rats were divided into three different groups (n = 6 each): control, diabetic, and thymoquinone-treated diabetic groups. Metabolites in serum samples were analyzed via gas chromatography-mass spectrometry. Multiple changes were observed, including those related to the metabolism of amino acids and fatty acids. The correlation analysis suggested that treatment with thymoquinone led to the reversal of diabetic nephropathy that was associated with modulations in the metabolism and proteolysis of amino acids, fatty acids, glycerol phospholipids, and organic acids. In addition, we explored the mechanisms linking the metabolic profiling of diabetic nephropathy, with a particular emphasis on the potential roles of increased reactive oxygen species production and mitochondrial dysfunctions. Our findings demonstrated that metabolomic profiling provided significant insights into the basic mechanisms of diabetic nephropathy and the therapeutic effects of thymoquinone.

Phytochemistry, pharmacology, and therapeutic uses of black seed (Nigella sativa)

Black seed (Nigella sativa) is an annual flowering plant from Ranunculaceae family, native to southwest Asia. This plant has many food and medicinal uses. The use of its seeds and oil is common for treatment of many diseases, including rheumatoid arthritis, asthma, inflammatory diseases, diabetes and digestive diseases. The purpose of this study was to provide a comprehensive review on the scientific reports that have been published about N. sativa. The facts and statistics presented in this review article were gathered from the journals accessible in creditable databases such as Science Direct, Medline, PubMed, Scopus, EBSCO, EMBASE, SID and IranMedex. The keywords searched in Persian and English books on medicinal plants and traditional medicine, as well as the above reputable databases were "Black seed", "Nigella sativa", "therapeutic effect", and "medicinal plant". The results showed that N. sativa has many biological effects such as anti-inflammatory, anti-hyperlipidemic, anti-microbial, anti-cancer, anti-oxidant, anti-diabetic, anti-hypertensive, and wound healing activities. It also has effects on reproductive, digestive, immune and central nervous systems, such as anticonvulsant and analgesic activities. In summary, it can be used as a valuable plant for production of new drugs for treatment of many diseases.

Ameliorative effects of thymoquinone against eye lens changes in streptozotocin diabetic rats

The possible protective effect of thymoquinone against eye lens changes in diabetic rats was investigated. Following diabetes induction by a single injection of streptozotocin (45 mg/kg, i.p.), thymoquinone was administered in three different doses (20, 40, and 80 mg/kg/day, p.o.) for 12 weeks. Thymoquinone significantly and dose-dependently attenuated the hypoinsulinemia and hyperglycemia in diabetic rats. Also, thymoquinone (particularly 40 and 80 mg/kg) significantly decreased the elevations of malondialdehyde, nitric oxide, tumor necrosis factor-α, glycated proteins, aldose reductase activity, sorbitol level, and caspase-3 activity in the lens tissues of diabetic rats. In addition, thymoquinone (particularly 40 and 80 mg/kg) significantly ameliorated the diabetes-induced reductions of glutathione peroxidase, superoxide dismutase, and catalase activities, and total and soluble protein contents in the lens tissues. It was concluded that thymoquinone significantly protected the lens tissue against changes induced by diabetes in rats through its antioxidant, anti-inflammatory, and antidiabetic effects.

Mechanisms of Thymoquinone Hepatorenal Protection in Methotrexate-Induced Toxicity in Rats

To investigate mechanisms by which thymoquinone (TQ) can prevent methotrexate- (MTX-) induced hepatorenal toxicity, TQ (10 mg/kg) was administered orally for 10 days. In independent rat groups, MTX hepatorenal toxicity was induced via 20 mg/kg i.p. at the end of day 3 of experiment, with or without TQ. MTX caused deterioration in kidney and liver function, namely, blood urea nitrogen, creatinine, alanine aminotransferase, and aspartate aminotransferase. MTX also caused distortion in renal and hepatic histology, with significant oxidative stress, manifested by decrease in reduced glutathione and catalase, as well as increase in malondialdehyde levels. In addition, MTX caused nitrosative stress manifested by increased nitric oxide, with upregulation of inducible nitric oxide synthase. Furthermore, MTX caused hepatorenal inflammatory effects as shown by increased tumor necrosis factor-α, besides upregulation of necrosis factor-κB and cyclooxygenase-2 expressions. MTX also caused apoptotic effect, as it upregulated caspase 3 in liver and kidney. Using TQ concurrently with MTX restored kidney and liver functions, as well as their normal histology. TQ also reversed oxidative and nitrosative stress, as well as inflammatory and apoptotic signs caused by MTX alone. Thus, TQ may be beneficial adjuvant that confers hepatorenal protection to MTX toxicity via antioxidant, antinitrosative, anti-inflammatory, and antiapoptotic mechanisms.

Altered transendothelial transport of hormones as a contributor to diabetes

The vascular endothelium is a dynamic structure responsible for the separation and regulated movement of biological material between circulation and interstitial fluid. Hormones and nutrients can move across the endothelium either via a transcellular or paracellular route. Transcellular endothelial transport is well understood and broadly acknowledged to play an important role in the normal and abnormal physiology of endothelial function. However, less is known about the role of the paracellular route. Although the concept of endothelial dysfunction in diabetes is now widely accepted, we suggest that alterations in paracellular transport should be studied in greater detail and incorporated into this model. In this review we provide an overview of endothelial paracellular permeability and discuss its potential importance in contributing to the development of diabetes and associated complications. Accordingly, we also contend that if better understood, altered endothelial paracellular permeability could be considered as a potential therapeutic target for diabetes.