The effects of transdermal insulin treatment of streptozotocin-induced diabetic rats on kidney function and renal expression of glucose transporters

The Antihyperglycemic Effect of Crude Liang (Gnetum gnemon var. tenerum) Leaves Powder on Wistar Rats

Chlorophyll and chlorophyllin (CHL) demonstrated antidiabetic activity by inhibiting gluconeogenesis and increasing glucose uptake in rats' muscle cells. Liang leaves contain high amounts of chlorophyll and chlorophyllin and may provide an antidiabetic effect. The antidiabetic activity of chlorophyll and CHL contained in Liang leaves, Cu-chlorophyllin (CCL) Liang leaves treated with CuSO4, and untreated crude Liang leaves (CLL) were compared using commercial chlorophyllin (CHL) as a reference. Twelve Wistar male rats were separated into 4 groups (3 rats/group); the first was a normal one (based line group), the second were the diabetic rats treated with CHL, while the third and the fourth were the diabetic rats treated with 0.97 g/kg of CCL and CLL, respectively. Diabetic rats were induced by a high fructose diet, before being taken to administer commercial CHL, CCL, and CLL for 7 days. Nonfasting blood glucose and body weight were checked daily. After euthanasia, organ weight, biochemical, hematological, and histopathological properties were evaluated. CCL treatment showed no antihyperglycemic activity in the rat model but caused some biochemical abnormalities and thrombocytopenia. Commercial CHL gave a higher reduction of nonfasting blood glucose (NFBG) than Liang leaves powder CCL or CLL but also showed some signs of abnormal biochemical parameters. CLL exhibited an antihyperglycemic effect, with higher body weight and increased HDL/LDL ratio and thus could be a promising alternative natural source for diabetes treatment.

Anacardium occidentale leaves extract and riboceine mitigate hyperglycemia through anti-oxidative effects and modulation of some selected genes associated with diabetes

Background

Diabetes mellitus (DM) is one of the leading causes of death globally and complications of DM have become a major health concern. Anacardium occidentale is a plant widely recognized for its hypoglycemic properties and traditionally used in developing nations as remedy for DM treatment. Riboceine is a supplement that enhances production of glutathione and known for its vital role in supporting cellular function. This study was designed to evaluate the antidiabetic and antioxidant potential of riboceine and ethanolic extract of A. occidentale leaves in streptozotocin (STZ)-induced diabetic rats.

Method

Twenty-nine adult male Wistar rats were induced with DM intraperitoneally using a single dose of STZ (70 mg/kg). The STZ-induced rats were divided into groups and administered the same dose (100 mg/kg) of A. occidentale leaves extract and riboceine via gastric gavage at the dose (100 mg/kg) for seventeen days while metformin (40 mg/kg) was used as positive control. Fasting blood glucose and weight of the model rats were examined periodically. Activities of total protein, creatinine, urea, antioxidants (SOD, GSH and GPX), and level of serum insulin were determined. Expression of diabetes related genes including pancreas (Insulin, pdx-1, P16NK4A, and Mki-67), Liver (FAS, ACC, and GFAT) and KIM-1 genes were also determined.

Results

Data showed that treatment of STZ-induced diabetic rats with A. occidentale and riboceine at the same dose significantly (p < 0.05) ameliorated hyperglycemic effects by improving hepatic and renal functions and antioxidants, preventing hepatic fat accumulation by downregulation of ACC, FAS and GFAT expression, improving β-cell functions through up-regulation of pancreatic insulin, P16NK4A, Mki-67 and pdx-1 expression. Induction of diabetes upregulated mRNA expression of KIM-1, which was ameliorated after treatment of the rats with A. occidentale and riboceine.

Conclusion

The results obtained in this study demonstrate significant antidiabetic properties of ethanolic extract of A. occidentale and riboceine.

Effect of Insulin on Proximal Tubules Handling of Glucose: A Systematic Review

Renal proximal tubules reabsorb glucose from the glomerular filtrate and release it back into the circulation. Modulation of glomerular filtration and renal glucose disposal are some of the insulin actions, but little is known about a possible insulin effect on tubular glucose reabsorption. This review is aimed at synthesizing the current knowledge about insulin action on glucose handling by proximal tubules. Method. A systematic article selection from Medline (PubMed) and Embase between 2008 and 2019. 180 selected articles were clustered into topics (renal insulin handling, proximal tubule glucose transport, renal gluconeogenesis, and renal insulin resistance). Summary of Results. Insulin upregulates its renal uptake and degradation, and there is probably a renal site-specific insulin action and resistance; studies in diabetic animal models suggest that insulin increases renal SGLT2 protein content; in vivo human studies on glucose transport are few, and results of glucose transporter protein and mRNA contents are conflicting in human kidney biopsies; maximum renal glucose reabsorptive capacity is higher in diabetic patients than in healthy subjects; glucose stimulates SGLT1, SGLT2, and GLUT2 in renal cell cultures while insulin raises SGLT2 protein availability and activity and seems to directly inhibit the SGLT1 activity despite it activating this transporter indirectly. Besides, insulin regulates SGLT2 inhibitor bioavailability, inhibits renal gluconeogenesis, and interferes with Na+K+ATPase activity impacting on glucose transport. Conclusion. Available data points to an important insulin participation in renal glucose handling, including tubular glucose transport, but human studies with reproducible and comparable method are still needed.

The pectin-insulin patch application prevents the onset of peripheral neuropathy-like symptoms in streptozotocin-induced diabetic rats

Peripheral neuropathic condition is amongst the classical symptoms of progressed diabetes. An intensive glycemic control with insulin injections has been shown to delay the onset and the progression of this condition in diabetes. In this study, we investigated the effect of pectin-insulin patch application on peripheral neuropathic symptoms in streptozotocin-induced diabetic rats. Pectin-insulin patches (20.0, 40.8, and 82.9 μg/kg) were daily applied thrice in streptozotocin-induced diabetic rats for 45 days. The diabetic animals sham treated with insulin-free patch served as negative control, while diabetic animals receiving subcutaneous insulin served as positive controls. The locomotor activity, gripping strength, and thermal perception were assessed at day 36, day 40, and day 44, respectively. On the 45th day, the animals were sacrificed, after which the plasma insulin, nitric oxide, C-reactive protein, tumor necrosis factor alpha, and malondialdehyde were measured. The patch application attenuated hyperglycemia with an improvement in the locomotor activity, thermal perception, and gripping strength in diabetic animals. Furthermore, the application of the patch augmented plasma nitric oxide while attenuating plasma malondialdehyde and tumor necrosis factor alpha. The application of pectin-insulin patch delays the onset of peripheral neuropathic-like symptoms in diabetic animals.

Xiexin Tang improves the symptom of type 2 diabetic rats by modulation of the gut microbiota

Type 2 diabetes mellitus (T2DM), a chronic metabolic disease which severely impairs peoples' quality of life, currently attracted worldwide concerns. There are growing evidences that gut microbiota can exert a great impact on the development of T2DM. Xiexin Tang (XXT), a traditional Chinese medicine prescription, has been clinically used to treat diabetes for thousands of years. However, few researches are investigated on the modulation of gut microbiota community by XXT which will be very helpful to unravel how it works. In this study, bacterial communities were analyzed based on high-throughput 16S rRNA gene sequencing. Results indicated that XXT could notably shape the gut microbiota. T2DM rats treated with XXT exhibited obvious changes in the composition of the gut microbiota, especially for some short chain fatty acids producing and anti-inflammatory bacteria such as Adlercreutzia, Alloprevotella, Barnesiella, [Eubacterium] Ventriosum group, Blautia, Lachnospiraceae UCG-001, Papillibacter and Prevotellaceae NK3B31 group. Additionally, XXT could also significantly ameliorate hyperglycemia, lipid metabolism dysfunction and inflammation in T2DM rats. Moreover, the correlation analysis illustrated that the key microbiota had a close relationship with the T2DM related indexes. The results probably provided useful information for further investigation on its active mechanism and clinical application.

The Effects of Momordica balsamina Methanolic Extract on Kidney Function in STZ-Induced Diabetic Rats: Effects on Selected Metabolic Markers

BACKGROUND

Studies suggest that Momordica balsamina (intshungu) possesses hypoglycaemic effects. The effects of Momordica balsamina on diabetic complications such as DN, however, have not been established. Accordingly, this study seeks to investigate the effects of M. balsamina on kidney function in STZ-induced diabetic rats.

METHODS

Methanolic extracts (ME) of M. balsamina's leaves were used in this study. Short-term effects of M. balsamina methanolic extract on kidney function and MAP were studied in STZ-induced diabetic rats treated twice daily with M. balsamina methanolic extract (250 mg/kg), insulin (175 μg/kg, s.c.), and metformin (500 mg/kg) for 5 weeks.

RESULTS

M. balsamina methanolic extract significantly increased Na⁺ excretion outputs in STZ-induced diabetic rats by comparison to STZ-diabetic control rats. M. balsamina methanolic extract significantly increased GFR in STZ-diabetic rats with a concomitant decrease in creatinine concentration and also reduced kidney-to-body ratio, albumin excretion rate (AER), and albumin creatinine ratio (ACR). M. balsamina methanolic extract significantly reduced MAP in STZ-diabetic animals by comparison with STZ-diabetic control animals. These results suggest that M. balsamina methanolic extract not only lowers blood glucose but also has beneficial effects on kidney function and blood pressure.

CONCLUSION

These findings suggest that M. balsamina may have beneficial effects on some processes that are associated with renal derangement in STZ-induced diabetic rats.

Cardioprotective effects of pectin-insulin patch in streptozotocin-induced diabetic rats

BACKGROUND

Cardiovascular complications are among the leading causes of morbidity and mortality in diabetes mellitus. Despite the beneficial effects of subcutaneous insulin, reports suggest that the therapy itself precipitates cardiovascular risks due to the high insulin concentration administered. It is therefore necessary to seek alternative routes of insulin administration that may bypass the undesirable effects associated with high plasma insulin concentrations. Accordingly, the present study investigated the effects of a novel transdermal pectin-insulin patch on selected markers of cardiovascular function in diabetes.

METHODS

Pectin-insulin matrix patches (20.0, 40.8, and 82.9 μg/kg) were prepared as described previously. The three formulations were applied to streptozotocin-induced diabetic rats thrice daily. Blood glucose concentrations and mean arterial pressure (MAP) were monitored weekly for 5 weeks. Rats were then killed and blood collected for analysis of the lipid profile, cardiotropin-1, tumor necrosis factor (TNF)-α, and high-sensitivity C-reactive protein (hsCRP).

RESULTS

The patches decreased blood glucose concentrations and diabetes-induced disturbances in lipid profile were attenuated by patch application (82.9 μg/kg). The diabetes-induced increase in MAP was also attenuated in patch (82.9 μg/kg)-treated rats. Patch treatment resulted in a decreased heart weight: body weight ratio, as well as reductions in cardiotropin-1, TNF-α, and hsCRP concentrations.

CONCLUSIONS

Application of the pectin-insulin patch protects against the debilitating cardiovascular effects associated with conventional diabetes treatment. This suggests that the pectin-insulin patch may provide an effective alternative therapeutic approach to the commonly used subcutaneous insulin injections in the management of diabetes.

Astragaloside IV prevents kidney injury caused by iatrogenic hyperinsulinemia in a streptozotocin‑induced diabetic rat model

Diabetic patients are able to manage their blood glucose with exogenous insulin but, ultimately, remain at risk of diabetic nephropathy (DN). Long‑term use of insulin may lead to iatrogenic hyperinsulinemia, which has been suggested to cause kidney injury. However, there are no effective interventions for iatrogenic hyperinsulinemia leading to kidney damage. In the present paper, the hypothesis that astragaloside IV (AS‑IV), a novel saponin purified from Astragalus membranaceus (Fisch) Bunge, may prevent DN in iatrogenic hyperinsulinemic diabetic rats through antioxidative and anti‑inflammatory mechanisms was investigated. Diabetes was induced with streptozotocin (STZ) (55 mg/kg) by intraperitoneal injection in rats. At 1 week following STZ injection, the diabetic rats were treated with Levemir subcutaneously for 4 weeks. Diabetic rat insulin levels >30 µU/ml were considered as iatrogenic hyperinsulinemia. Rats were divided into six groups (n=8 per group): Iatrogenic hyperinsulinemic rats, and iatrogenic hyperinsulinemic rats treated with Tempol and AS‑IV at 2.5, 5 and 10 mg/kg/day, intragastric infusion, for 12 weeks. The normal rats were used as a non‑diabetic control group. AS‑IV ameliorated albuminuria, mesangial cell proliferation, basement membrane thickening and podocyte foot process effacement in iatrogenic hyperinsulinemic rats. In iatrogenic hyperinsulinemic rat renal tissues, malondialdehyde, interleukin‑1β (IL‑1β), tumor necrosis factor‑α (TNF‑α), type IV collagen and laminin levels were increased, whereas glutathione peroxidase and superoxide dismutase activity levels were decreased. Nicotinamide adenine dinucleotide phosphate oxidase 4 expression and extracellular signal‑regulated kinase 1/2 (ERK1/2) activation were upregulated, and canonical transient receptor potential cation channel 6 (TRPC6) protein expression was downregulated. However, all these abnormalities were attenuated by AS‑IV. These findings suggested that AS‑IV prevented rat kidney injury caused by iatrogenic hyperinsulinemia by inhibiting oxidative stress, IL‑1β and TNF‑α overproduction, downregulating ERK1/2 activation, and upregulating TRPC6 expression.

Quercetin nanoparticle complex attenuated diabetic nephropathy via regulating the expression level of ICAM-1 on endothelium

The purpose of the study was to reveal the therapeutic effect of quercetin (QUE) nanoparticle complex on diabetic nephropathy (DN) by regulating the expression of intercellular adhesion molecular-1 (ICAM-1) on endothelium as compared to free QUE. QUE 10 mg/kg as a single abdominal subcutaneous injection daily for 8 weeks continuously in diabetic rats and 10 mg/kg QUE nanoparticle complex as a single abdominal subcutaneous injection every 5 days, continuously administered for 8 weeks to diabetic rats. Blood and left kidneys were collected; pathological change of kidney, renal function, oxidative stress level, blood glucose level, serum lipid, urine protein, and albumin/creatinine ratio were measured; and neutrophil adhesion, ICAM-1 expression, and CD11b⁺ cells infiltration were observed. Both QUE and QUE nanoparticle complex preconditioning ameliorated the pathological damage of kidney and improved renal function, alleviated renal oxidative stress injury, restricted inflammatory cells infiltration, and downregulated the ICAM-1 expression as compared to DN group, while QUE nanoparticle complex significantly alleviated this effect.

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.

The Effects of Transdermally Delivered Oleanolic Acid on Malaria Parasites and Blood Glucose Homeostasis in P. berghei-Infected Male Sprague-Dawley Rats

The present study investigated the effects of transdermally delivered oleanolic acid (OA) monotherapy and in combination with chloroquine (CHQ) on malaria parasites and glucose homeostasis of P. berghei-infected male Sprague-Dawley rats. Oral glucose test (OGT) responses to OA-pectin patch and CHQ-OA combination matrix patch were monitored in non-infected and infected rats. To evaluate the short-term effects of treatment, percentage parasitaemia, blood glucose, glycogen and plasma insulin were monitored in separate groups of animals treated with either OA-patch monotherapy or CHQ-OA combination pectin patch over a 21-days period. Animals treated with drug-free pectin and CHQ acted as untreated and treated positive controls, respectively. Infected control rats exhibited significantly increased parasitaemia which was accompanied by hypoglycaemia. Both OA monotherapy and CHQ-OA combination therapy reduced and cleared the malaria parasites within a period of 4 and 3 days, respectively. Compared to respective controls groups, OGT responses of animals treated with OA monotherapy or CHQ-OA combination therapy exhibited lower blood glucose levels at all time points. A once-off transdermal application of OA-patch or CHQ-OA combination patch significantly improved blood glucose concentrations inducing any changes in insulin concentration. Transdermal OA used as a monotherapy or in combination with CHQ is able to clear and reduce the malaria parasites within a shorter period of time without eliciting any adverse effects on glucose homeostasis of P. berghei-infected rats.

Effect of Streptozotocin on Plasma Insulin Levels of Rats and Mice: A Meta-analysis Study

BACKGROUND:

In the studies focusing on diabetic organisms, Streprozotocine (STZ) is a frequently used agent to induce diabetes in rats and mice. However the current studies do not represent practical importance of their statistical findings. For showing practical importance of the differences in plasma insulin levels of diabetic rats and mice induced by STZ, there should be a statistical synthesis regarding statistical findings of the studies.

AIM:

The purpose of this study is to make a meta-analysis of the studies on the effect of STZ on plasma insulin levels in diabetic rats and mice.

MATERIALS AND METHODS:

In this study 39 effect sizes (37 studies) about levels of plasma insulin were analyzed by calculating individual effect sizes (d) and mean effect size.

RESULTS:

The effect sizes were between -13.7 and +65.3 and the mean effect size value (+9.33) represented a large effect indicating that STZ was an effective agent to significantly decrease plasma insulin levels of diabetic rats and mice.

CONCLUSION:

It can be said that the differences in plasma insulin levels between STZ-applied and no application groups has a practical importance in making animal model of diabetes.