Umbelliferone ameliorates oxidative stress and testicular injury, improves steroidogenesis and upregulates peroxisome proliferator-activated receptor gamma in type 2 diabetic rats.

OBJECTIVES: Diabetes mellitus (DM) is a chronic disease associated with serious complications, including male infertility. Umbelliferone (UMB) is a coumarin with promising antioxidant, anti-inflammatory and other beneficial effects. This study investigated the ameliorative effect of UMB against testicular injury, oxidative stress and altered steroidogenesis in rats with type 2 DM. METHODS: Rats received a high fat diet for 4 weeks followed by a single injection of streptozotocin. Diabetic rats were treated with UMB or pioglitazone (PIO) for 6 weeks and samples were collected for analysis. KEY FINDINGS: Diabetic rats exhibited hyperglycemia, insulin resistance and dyslipidemia associated with increased serum pro-inflammatory cytokines, and decreased gonadotropins and testosterone. UMB significantly ameliorated metabolic alterations, decreased pro-inflammatory cytokines, and increased gonadotropins and testosterone levels. UMB prevented testicular injury, suppressed lipid peroxidation and nitric oxide and increased antioxidants in diabetic rats. In addition, UMB upregulated testicular gonadotropins receptors, steroidogenesis markers (steroidogenic acute regulatory protein, cytochrome P450 family 17 subfamily A member 1 [CYP17A1], 3ß-hydroxysteroid dehydrogenase [3ß-HSD] and 17ß-hydroxysteroid dehydrogenase [17ß-HSD]), and peroxisome proliferator-activated receptor gamma (PPARγ) expression. CONCLUSIONS: UMB prevents testicular injury by preventing metabolic alterations, suppressing oxidative damage and inflammation, and boosting antioxidant defenses in diabetic rats. UMB enhanced pituitary-gonadal axis and steroidogenesis and upregulated testicular PPARγ in diabetic rats. Thus, UMB may represent a protective agent against testicular injury and sexual dysfunction associated with chronic hyperglycemia.

Dipeptidyl peptidase-4 inhibitors and aerobic exercise synergistically protect against liver injury in ovariectomized rats.

Menopause increases the risk of non-alcoholic fatty liver disease (NAFLD). We investigated the effect of incretin and/ or exercise on the hepatic fat accumulation in ovariectomized rats. Rats were divided into five groups: Group 1: Control rats, Group 2: Ovariectomized rats, Group 3: Ovariectomized rats + Dipeptidyl peptidase-4 inhibitor (DPPi) (30 mg/kg/day, orally), Group 4: Ovariectomized rats + swimming, and Group 5: Ovariectomized rats + swimming + DPPi. After 6 weeks, Alanine aminotransferase (ALT), glucose, insulin, HOMA IR (Homeostatic Model Assessment for Insulin Resistance), FFA (free fatty acids), Tumor necrosis factor alpha (TNF α), IL6, IL1B levels were measured in blood. The livers were collected for Hematoxylin and eosin (H&E) examination and evaluation of hepatic gene expression of SREBP (sterol regulatory element-binding protein1c), PPAR α (peroxisome proliferator-activated receptor alpha), ACC 1 (acetyl-CoA carboxylase), LC3 (microtubule-associated protein 1 light chain 3), SIRT (sirtuin), hepatic triglycerides, IL6, IL10, caspase 3 and AMPK (adenosine monophosphate-activated protein kinase). A significant increase in ALT level and area of liver tissue defects with a significant increase in glucose HOMA IR, serum FFA, IL6, IL1B, TNF α, liver TGs (triglycerides), inflammation, apoptosis, SREBP1c, ACC1 were found in ovariectomized rats as compared to control group with a significant decrease in PPAR α, LC3, AMPK and SIRT1. DPPi treated rats with and without exercise showed a significant improvement in ALT and area of liver tissue defects, inflammation and apoptosis and serum IL6, IL1B, TNF α, FFA, liver LC3, SIRT1, AMPK, TGs, PPAR α, ACC1 and SREBP1c as compared to the ovariectomized group. Findings from the study confirm the derangement of fat metabolism in the ovariectomized rats and showed that incretin-based therapy and exercise synergistically improved liver fat metabolism, achieved significant beneficial metabolic effects and offer full protection against NAFLD.

Mesenchymal stem cells pretreated with melatonin ameliorate kidney functions in a rat model of diabetic nephropathy.

The aim of this study was to investigate the effect of a regenerative therapy comprising mesenchymal stem cells (MSCs) pretreated with melatonin (MT) as a new therapy for underlying diabetic nephropathy (DN) pathogenesis in a rat model, and its possible effect on autophagy protein Beclin-1. Forty adult male albino Wistar rats were distributed among 4 groups: (i) control, (ii) DN, (iii) MSC-treated, and (iv) treated with MSCs that were pre-incubated in-vitro with MT (5 µmol·L-1 for 24 h; MSCs + MT). MSCs treatment significantly improved the renal functions and ameliorated the measured underlying DN pathogenesis and elevation of Beclin-1 protein levels compared with the DN group. In-vitro pretreatment of MSCs with MT enhanced proliferation and efficiency, and thus improved the kidney functions by increasing superoxide dismutase (SOD-1) and Beclin-1, and decreasing transforming growth factor (TGF-ß) markers in the kidney tissue, compared with the MSC group (P < 0.05). In conclusion: MSCs represent a promising target in DN management, and their effect can be intensified by pretreatment with MT. The elevated levels of Beclin-1 could be a mediator.

The protective effect of 1alpha, 25-dihydroxyvitamin d3 and metformin on liver in type 2 diabetic rats.

There is an accumulating evidence suggesting an immunomodulatory role of 1α,25(OH)2D3. Altered 1α,25(OH)2D3 level may play a role in the development of T2DM and contribute to the pathogenesis of liver diseases. Our study was designed to study and compare the effect of metformin and 1α,25(OH)2D3 supplementation on liver injury in type 2 diabetic rat. Sixty male Albino rats were divided into 5 groups; group 1: control rats. the remaining rats were fed high fat diet for 2 weeks and injected with streptozotocin (35mg/kg BW, i.p.) to induce T2DM and were divided into: group 2: untreated diabetic rats, group 3: diabetic rats treated by metformin (100mg/kgBW/d, orally), group 4: diabetic rats supplemented by 1α,25(OH)2D3 (0.5µg/kg BW, i.p.) 3 times weekly and group 5: supplemented by both 1α,25(OH)2D3 and metformin. Eight weeks later, serum glucose and insulin levels were measured, HOMA IR was calculated, lipid profile, Ca2+, ALT and AST were estimated. Liver specimens were taken to investigate PPAR-α (regulator of lipid metabolism), NF-κB p65, caspase 3 and PCNA (proliferating cell nuclear antigen) and for histological examination. The liver enzymes were elevated in the diabetic rats and the histological results revealed an injurious effect of diabetes on the liver. 1α,25(OH)2D3, metformin and both drugs treatment significantly improved liver enzymes as compared to the untreated rats. The improvement was associated with a significant improvement in the glycemic control, lipid profile and serum Ca2+ with a significant reduction in NF-κB p65 and caspase 3 and increased PPAR-α, and PCNA expression as compared to the untreated group. 1α,25(OH)2D3 induced a slightly better effect as compared to metformin. Both agents together had a synergistic action and almost completely protected the liver. Histological results confirmed the biochemical findings. Our results showed a protective effect of 1α,25(OH)2D3 and metformin on liver in diabetic rats as indicated by an improvement of the level of the liver enzymes, decreased apoptosis and increased proliferation and this was confirmed histologically, with modulating NFkB and PPAR-α. Both agents together had a synergistic effect.

A study on the effect of cimetidine and L-carnitine on myoglobinuric acute kidney injury in male rats.

Myoglobinuric acute renal failure is the most important life threatening complication of rhabdomyolysis. Iron, free radicals, nitric oxide and cytochrome p450 are involved in the pathogenesis of mARF. The aim of this study is to compare the effect of cimetidine, l-carnitine and both agents together on mARF in rats. Forty rats were divided into 5 groups; group I: control rats, group II: myoglobinuric ARF rats, group III: mARF rats received l-carnitine (200mg/kg, i.p.), group IV: mARF rats received cimetidine (150mg/kg i.p.) and group V: mARF rats received both agents together. 48h after glycerol injection, systolic blood pressure was measured. Urine and blood samples were collected to evaluate urine volume, GFR, BUN, creatinine, K, Na, serum creatine kinase, NO and glutathione levels. Kidney specimens were taken to investigate renal cytochrome p450 and for histological examinations. Cimetidine treatment significantly decreased creatinine, BUN, K, Na, SBP and creatine kinase and increased GFR and urine volume compared to group II. l-carnitine exerted similar changes except for the effect on K and GFR. NO was significantly decreased, while renal glutathione and cytochrome p450 were significantly increased in groups treated with l-carnitine or cimetidine as compared to group II. Combined treatment further improved renal functions, creatine kinase, oxidative stress parameters and SBP as compared to each therapy alone. The histological changes confirmed the biochemical findings. Cimetidine and l-carnitine have protective effects - almost equally - against mARF. Using both agents together, minimises the renal injury.