Effect of experimental diabetes mellitus on gentamicin-induced acute renal functional changes in the anaesthetized rat

Antidiabetic properties and mechanism of action of Orthosiphon stamineus Benth bioactive sub-fraction in streptozotocin-induced diabetic rats

Orthosiphon stamineus is a popular folk medicine widely used to treat many diseases including diabetes. Previous studies have shown that the sub-fraction of chloroform extract was able to inhibit the rise of blood glucose levels in a glucose tolerance test. This study was carried out to evaluate the chronic effect and possible mechanism of action of the bioactive chloroform sub-fraction of O. stamineus using streptozotocin-induced diabetic rats and in vitro methods. Administration of the chloroform extract sub-fraction 2 (Cƒ2-b) at a dose of 1 g/kg twice daily on diabetic rats for 14 days showed a significant lowering (p < 0.05) of the final blood glucose level compared to the pretreatment level. However, there were no significant differences in the plasma insulin levels post-treatment compared to the pretreatment levels for all doses of Cƒ2-b. Conversely, Cƒ2-b at a concentration of 2 mg/mL significantly increased (p < 0.001) the glucose uptake by the rat diaphragm muscle. The increase in glucose uptake was also shown when the muscle was incubated in a solution containing 1 IU/mL of insulin or 1 mg/mL of metformin. Furthermore, the effect of this sub-fraction on glucose absorption in the everted rat jejunum showed that Cƒ2-b at concentrations of 0.5 mg/mL, 1 mg/mL and, 2 mg/mL significantly reduced the glucose absorption of the jejunum (p < 0.05-0.001). Similarly, the absorption of glucose was also inhibited by 1 mg/mL and 2 mg/mL of metformin (p < 0.001). These results suggest that the effect of Cƒ2-b may be due to extra-pancreatic mechanisms. There was no evidence that the plant extract stimulated the release of insulin in order to lower the blood glucose level.

Outcome of acute renal injury in diabetic mice with experimental endotoxemia: role of hypoxia-inducible factor-1 α

The role of diabetic nephropathy in the outcome of acute renal injury (AKI) is not well defined. Herein we evaluate the outcome of lipopolysaccharide- (LPS-) induced AKI in streptozotocin-induced diabetes, as well as the potential role of Hypoxia Inducible Factor (HIF-1 α ) in this condition. Although 6 h after LPS injection all mice developed a decrease in renal function, proteinuric diabetic mice showed a better recovery of this parameter throughout the study (72 h). Both HIF-1 α and vascular endothelium growth factor (VEGF) were found to be upregulated in diabetic mice. After LPS injection, all animals showed an upregulation of these factors, although it was higher in the diabetic group. Glycated albumin (GA) was found to upregulate HIF-1 α in HK-2 cells, which resulted in increased production of VEGF. Interestingly, LPS cooperated with GA to induce HIF-1 α upregulation. In conclusion, diabetic mice display a better recovery of AKI after experimental endotoxemia. Moreover, these animals showed an increased expression of both HIF-1 α and VEGF that was reproduced by incubating renal cells with GA. Since VEGF is considered a survival factor for tubular cells, our findings suggest that diabetes displays HIF-1 α upregulation that might function as a "precondition state" offering protection from endotoxic AKI.

Beneficial effect of the leaves of Murraya koenigii (Linn.) Spreng (Rutaceae) on diabetes-induced renal damage in vivo

ETHNOPHARMACOLOGICAL RELEVANCE

Murraya koenigii (Linn.) Spreng (curry leaf) is widely used as a nephroprotective agent in kidney's infirmities among diabetics by the traditional practitioners in Malaysia. However, the latter role of curry leaf has been grossly under reported and is yet to receive proper scientific evaluation.

AIM OF THE STUDY

The present study was designed to investigate the beneficial effect of the leaves of Murraya koenigii (Linn.) on diabetes-induced renal damage in vivo with regard to prove its efficacy by local traditional practitioners in the treatment of kidney frailties in diabetics.

MATERIALS AND METHODS

Aqueous (AQ) extract of the leaves of Murraya koenigii (Linn.) was administered to both normal and streptozotocin (STZ) induced diabetic male rats (Sprague-Dawley strain). Animals were divided into six groups (n=6) and treated with variable dose levels of AQ extract (200 and 400mg/kg body weight/day) for 30 days. At the end of 30 days, animals were sacrificed, blood was collected, processed and stored at -70°C for the zestimation of serum urea and creatinine, changes in plasma antioxidant capacity by FRAP assay, and glutathione peroxidase levels, in the normal and STZ-induced diabetic rats. Histological changes of the kidneys of these animals were also evaluated by light microscopy to determine the beneficial effect of the leaves.

RESULTS

Daily oral administration of variable dose levels of the AQ extract for 30 days, produced significant dose dependant decrease in serum urea and creatinine levels (p<0.001), and marked increase in the levels of plasma antioxidant capacity (p<0.01) in diabetic treated rats, compared to the control (non-diabetic) subjects. However, the normal treated rats showed minimal variation in these parameters in comparison to normal controls. Histological studies of the kidneys of these animals showed comparable tissue regeneration by the AQ extract.

CONCLUSION

The results of our study scientifically support the traditional belief for using the leaves of Murraya koenigii (Linn.) as adjuvant, in the treatment of pain disorders related to renal impairments among diabetics.

Aminoglycosides and Kidney Function

The aminoglycosides are bactericide antibiotics with predominant effecting on the Gramm-negative bacteries, then staphylococci and mycobacteria with a small therapeutic range and with expressive ototoxic, nephrotoxic and with rare neurotoxic side effects. In this work the value of creatinine are investigated in serum of patients who are hospitalized in Internal department of the Health Center in Kosovska Mitrovica, before, in the course of and after therapy with the aminoglycosides antibiotics were given in different doses. The creatinine was determined by kinetic method (Jaffe). The significant increasing of creatinine values in serum was recorded with the groups of patients who have got gentamicine 2x120 mg i.m., gentamicine 2x120 mg in combination with furosemide, the gentamicine 2x120 mg with the patients with diabetes mellitus, gentamicine 2x120 mg in the course of 14 days until with the groups who have been getting gentamicine 1x120 mg, gentamicine 2x80 mg and amikacine 2x500 mg were not recorded the significant increased values of creatinine. The determination of creatinine for the sake of the following degree damage of kidney function in the course therapy of the aminoglycosides was very important.

Antidiabetic, Antioxidant and Antihyperlipidemic Status of Heliotropium zeylanicum Extract on Streptozotocin-Induced Diabetes in Rats

The potential role of the methanolic extract of Heliotropium zeylanicum (BURM.F) LAMK (MEHZ) in the treatment of diabetes along with its antioxidant and antihyperlipidemic effects was studied in streptozotocin-induced diabetic rats. Oral administration of (MEHZ) 150 and 300 mg/kg/d for 14 d significantly decreased the blood glucose level and considerably increased the body weight, food intake, and liquid intake of diabetic-induced rats. MEHZ significantly decreased thiobarbituric acid reactive substances and significantly increased reduced glutathione, superoxide dismutase and catalase in streptozotocin-induced diabetic rats at the end of 14 d of treatment. The study also investigated the antihyperlipidemic potential of MEHZ. The results show that the active fraction of MEHZ is promising for development of a standardized phytomedicine for the treatment of diabetes mellitus.

Antihyperglycemic effect of aqueous and ethanolic extracts of Gongronema latifolium leaves on glucose and glycogen metabolism in livers of normal and streptozotocin-induced diabetic rats

The present study was designed to investigate the antihyperglycemic effects of aqueous and ethanolic extracts from Gongronema latifolium leaves on glucose and glycogen metabolism in livers of non-diabetic and streptozotocin-induced diabetic rats. To investigate the effects of aqueous or ethanolic leaf extracts of G. latifolium, non-diabetic and STZ diabetic rats were treated twice daily (100 mg/Kg) for two weeks. Diabetic rats showed a significant decrease in the activities of hepatic hexokinase (HK), phosphofructokinase (PFK) and glucose-6-phosphate dehydrogenase (G6PDH) and an increase in glucokinase (GK) activity. The levels of hepatic glycogen and glucose were also increased in diabetic rats. However, there were no significant differences in the activities of glucose-6-phosphatase (G6Pase) in treated and untreated diabetic rats. The ethanolic extract significantly increased the activities of HK (p<0.01), PFK (p<0.001) and G6PDH (p<0.01) in diabetic rats, decreased the activity of GK (p<0.05) and the levels of hepatic glycogen (p<0.01) and both hepatic (p<0.001) and blood glucose (40%). The aqueous extract of G. latifolium was only able to significantly increase the activities of HK and decrease the activities of GK but did not produce any significant change in the hepatic glycogen and both hepatic and blood glucose content of diabetic rats. Our data show that the ethanolic extract from G. latifolium leaves has antihyperglycemic potency, which is thought to be mediated through the activation of HK, PFK, G6PDH and inhibition of GK in the liver. The ethanolic extract is under further investigation to determine the chemical structure of the active compound(s) and its/their mechanism of action.

Effects of Averrhoa bilimbi leaf extract on blood glucose and lipids in streptozotocin-diabetic rats

The present study was designed to investigate the hypoglycemic and hypolipidemic activities of an ethanolic extract of Averrhoa bilimbi Linn. leaves (Oxalidaceae, Common name: Bilimbi) in streptozotocin (STZ)-diabetic rats. The optimal hypoglycemic dose (125 mg kg(-1)) was determined by performing the oral glucose tolerance test (OGTT) in both normal and STZ-diabetic rats. To investigate the effect of repeated administration of an ethanolic extract of Averrhoa bilimbi (ABe) leaves, diabetic rats were treated with vehicle (distilled water), ABe (125 mg kg(-1)) or metformin (500 mg kg(-1)) twice a day for 2 weeks. Like metformin, ABe significantly lowered blood glucose by 50% and blood triglyceride by 130% when compared with the vehicle. ABe also significantly increased the HDL-cholesterol concentrations by 60% compared with the vehicle. ABe thus significantly increased the anti-atherogenic index and HDL-cholesterol/total cholesterol ratio. However, like metformin, ABe did not affect total cholesterol and LDL-cholesterol concentrations, but significantly reduced the kidney lipid peroxidation level. These data show that ABe has hypoglycemic, hypotriglyceridemic, anti-lipid peroxidative and anti-atherogenic properties in STZ-diabetic rats.