Influence of intranasal exposure of MPTP in multiple doses on liver functions and transition from non-motor to motor symptoms in a rat PD model.

Besides the effects on the striatum, the impairment of visceral organs including liver functions has been reported in Parkinson's disease (PD) patients. However, it is yet unclear if liver functions are affected in the early stage of the disease before the motor phase has appeared. The aim of our present study was thus to assess the effect of intranasal administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) in different doses on striatum and liver functions. Deterioration of non-motor activities appeared on single exposure to MPTP along with rise in striatum oxidative stress and decline in antioxidant levels. Decreases in dopamine, noradrenaline, and GABA and increase in serotonin were detected in striatum. Motor coordination was impaired with a single dose of MPTP, and with repeated MPTP exposure, there was further significant impairment. Locomotor activity was affected from second exposure of MPTP, and the impairment increased with third MPTP exposure. Impairment of liver function through increase in serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels was observed after first MPTP insult, and it worsened with second and third administrations. First administration of MPTP triggered systemic inflammation showing significant increase in inflammatory markers in the liver. Our data shows for the first time that an intranasal route of entry of MPTP affects liver from the non-motor phase of PD itself, occurring concomitantly with the reduction of striatal dopamine. It also suggests that a single dose is not enough to bring about progression of the disease from non-motor to locomotor deficiency, and a repeated dose is needed to establish the motor severity phase in the rat intranasal MPTP model.

Phloroglucinol, a nutraceutical for IR-induced cardiac damage in diabetic rats.

BACKGROUND: Myocardial injury due to ischemia-reperfusion (IR) is aggravated in diabetes which is associated with oxidative stress. Alleviating oxidative stress via use of antioxidants has been shown to be effective at minimizing myocardial cell death and improving cardiac function. The aim of the present study was to evaluate the cardioprotective effect of phloroglucinol against myocardial reperfusion injury (MRI) in diabetic rats. METHODS: Diabetes was induced in female rats with streptozotocin (50 mg/kg). The diabetic rats were orally treated with phloroglucinol (100 and 200 mg/kg daily for 28 days). After treatment the hearts were isolated and mounted on a Langendorff apparatus. The hearts were subjected to 15 minutes of IR to induce myocardial damage. Cardiac functions including heart rate (HR), resting and developed tension, and rate of change of contraction (+dP/dt max) were recorded. Cardiac injury biomarkers lactate dehydrogenase (LDH) and creatine kinase (CK-MB) were measured in the heart perfusate. Levels of the antioxidant enzymes reduced glutathione (GSH) and malondialdehyde (MDA) were measured. Hematoxylin and eosin (H&E) staining was also performed. RESULTS: After IR injury, a decrease in HR and +dP/dt max in hearts from diabetic rat was seen compared to healthy rat hearts, which was reversed by phloroglucinol treatment. Myocardial infarct size, measured by H&E staining, was increased in diabetic rats compared to healthy rats and an increase in the activity of LDH and CK-MB in the heart perfusate in diabetic rats was decreased by phloroglucinol treatment. An increase in MDA levels and a decrease in levels of antioxidant enzymes were observed in diabetic rats, which was reversed with phloroglucinol treatment. CONCLUSION: Phloroglucinol treatment has potential therapeutic promise in the treatment of MRI in diabetes.

Allantoin attenuates deficits of behavioural and motor nerve conduction in an animal model of cisplatin-induced neurotoxicity in rats.

BACKGROUND: The aim of the present study was to evaluate the neuroprotective effect of allantoin in cisplatin-induced toxicity in rats. METHODS: Adult male Wistar rats weighing 160-200 g were used. Neuropathy was induced by injecting cisplatin (2 mg/kg, ip, twice a week for 6 weeks) and the rats were concurrently treated with allantoin (200 and 400 mg/kg, po) for 8 weeks. At the end of the study, body weight and hemogram were measured. Behavioural tests were performed, including tests for cold and hot hyperalgesia, motor co-ordination, locomotor activity, mechano-tactile allodynia and mechanical hyperalgesia. The rats were then sacrificed and sciatic nerve conduction velocity was determined. The antioxidant enzyme and nitric oxide levels in sciatic nerve homogenates were measured. RESULTS: In this study, allantoin restored the motor nerve conduction velocity deficits induced by cisplatin, and the allantoin-treated rats showed improvement in cold and thermal hyperalgesia, mechano-tactile allodynia, and mechanical hyperalgesia. Allantoin treatment also improved the rats' hematological status, increasing haemoglobin, platelet and RBC counts compared to the cisplatin-treated group. Allantoin treatment also mitigated the functional abnormalities seen in the cisplatin neuropathy group, protecting neurons from the neurotoxic effects of cisplatin. CONCLUSION: Allantoin shows promise for use as an adjuvant drug in cancer treatment to protect against cisplatin-induced neuropathy.

Impact of diabetes on male sexual function in streptozotocin-induced diabetic rats: Protective role of soluble epoxide hydrolase inhibitor.

Diabetes-induced male sexual dysfunction is associated with endothelial dysfunction. Inhibition of soluble epoxide hydrolase (sEH) is known to improve endothelial function in diabetes. Therefore, we hypothesized that sEH inhibitor (sEHI), [trans-4-{4-[3-(4-trifluoromethoxyphenyl)-ureido]cyclohexyloxy}benzoic acid] / t-TUCB can restore the male sexual function in diabetic rat. After one week of administration of diabetogenic agent STZ (52 mg/kg i.p) injection, diabetic rats were treated with t-TUCB (0.1 and 0.3 mg/kg, p.o) or vehicle for 8 weeks. The sexual behaviour parameters of the animals were evaluated at the end of dosing period. The levels of testosterone and glucose in serum, and sperm were quantified. Effect of treatment on weight of reproductive organs and histopathology of penile tissue was evaluated. Diabetes had a negative effect on male sexual function, weight of sexual organs and production of sperm with a parallel decrease in the level of testosterone. The sEHI, t-TUCB, significantly preserved the sexual function and minimized an increase in the level of blood glucose in diabetic rats. It also prevented a decrease in the level of testosterone and sperm in diabetic rats, in comparison to diabetic control rats. Further, diabetes induced distortion of corpus cavernosum was attenuated by t-TUCB. Based on our findings, sEHI may delay the development of sexual dysfunction in diabetes.

Potential of phloroglucinol to improve erectile dysfunction associated with streptozotocin-induced diabetes in rats.

OBJECTIVE: Diabetes is a common metabolic disease with several complications in its patients. Often, people living with diabetes develop erectile dysfunction (ED). The primary aim of this work was to investigate the effect of phloroglucinol in diabetes-induced ED in rats. METHODS: Male Wistar rats were given 52 mg/kg of streptozotocin, by intraperitoneal injection, to induce diabetes and ED. Subsequently, animals were grouped into three groups: group 1, diabetic control; group 2, low-dose phloroglucinol (150 mg/kg body weight); and group 3, high-dose phloroglucinol (250 mg/kg body weight). A group of six normal rats served as a normal control. The rats were treated with phloroglucinol for six weeks and then were assessed for treatment effects. Sexual behavior, glycosylated hemoglobin A1c (HbA1c) values, serum testosterone, serum nitric oxide (NO), blood pressure and sperm count were measured after the end of treatment. RESULTS: After a 6-week treatment period, the high dose of phloroglucinol significantly decreased HbA1c values in diabetic rats. Rats treated with phloroglucinol had increased serum testosterone, NO and sperm count. Animals treated with 250 mg/kg phloroglucinol performed similar to normal rats in the sexual behavioral study, suggesting the reversal of complications of ED. Conversely, a decrease in the blood pressure in treated groups was observed. CONCLUSION: The results highlight the protective effect of phloroglucinol in diabetes-induced ED in rats warranting further studies.

An inhibitor of soluble epoxide hydrolase ameliorates diabetes-induced learning and memory impairment in rats.

BACKGROUND: Pharmacological inhibition of soluble epoxide hydrolase (sEH) enhances the synaptic function in the CNS and has a protective role in cognitive decline. We hypothesized that the sEH inhibitor TPPU might prevent the diabetes-induced decline in learning and memory which is associated with an alteration in the level of neurotransmitters and oxidative stress. METHODS: Type 1 diabetes was induced in rats and the animals were treated with TPPU for 8 weeks. The learning and memory functions were assessed by the Barnes maze and a step-down test. Indicators of oxidative stress, levels of neurotransmitters, and activity of acetylcholinesterase were measured in the discrete regions of the brain. RESULTS: Our results revealed that treatment with TPPU significantly improves learning and memory performance in diabetic rats along with decreasing the level of blood sugar. Moreover, treatment with TPPU significantly prevented the diabetes-induced alteration in levels of neurotransmitters, the activity of acetylcholinesterase and preserved anti-oxidant defence system. CONCLUSION: Inhibition of the sEH alleviates diabetes-induced decline in learning and memory.

Repositioning of molsidomine for its efficacy in diabetes induced erectile dysfunction in rats: In silico, in vitro and in vivo approach.

BACKGROUND: Well known risk factors for diabetic erectile dysfunction include impaired nitric oxide synthesis and endothelial dysfunction. We proposed to evaluate the efficacy of nitric oxide donor, molsidomine in rat model of diabetic erectile dysfunction. METHODS: Streptozotocin (52mg/kg, ip) induced diabetic male rats were treated with molsidomine (5 and 10mg/kg, po) for 8 weeks. The sexual behaviour of male rat in presence of the female rat in oestrous phase was observed at the end of study. The effect of treatment on serum testosterone level, sperm parameters and penile tissue histopathology was also evaluated. Further anti-inflammatory activity and antioxidant potential of molsidomine was evaluated by in vitro method. In silico docking study was carried out to appreciate binding conformation of the molsidomine to its plausible target, phosphodiesterase enzyme. RESULTS: Molsidomine significantly and dose dependently increased sexual behaviour, sperm count and serum testosterone level in diabetic rats. Further, the protective effect of molsidomine was also substantiated by pathological changes in the architect of the penile tissue. Molsidomine showed good membrane stability accounting for its significant anti-inflammatory action and also significantly scavenged DPPH radical activity showing its antioxidant action. Molsidomine was found to settle well in the active site of PDE-5 enzyme with less binding affinity than the standard drug sildenafil. CONCLUSION: The results highlight the rationale behind the repositioning of molsidomine therapy for the management of diabetic erectile dysfunction.

Nebivolol, a ß-blocker abrogates streptozotocin-induced behavioral, biochemical, and neurophysiological deficit by attenuating oxidative-nitrosative stress: a possible target for the prevention of diabetic neuropathy.

Metabolic abnormalities including hyperglycemia, hyperlipidemia, and oxidative-nitrosative stress are involved in the progression of diabetic neuropathy. In the present study, we targeted oxidative-nitrosative stress using nebivolol, a ß1-receptor antagonist with vasodilator and antioxidant property, to evaluate its neuroprotective effect in streptozotocin-induced diabetic neuropathy in rats. Diabetic neuropathy develops within 4-6 weeks after administration of streptozotocin (55 mg/kg, i.p.). Therefore, after confirmation of diabetes, subtherapeutic doses of nebivolol (1 and 2 mg/kg, p.o./day) were given to diabetic rats for 8 weeks. Nebivolol treatment significantly improved thermal hyperalgesia, grip strength, and motor coordination. Nebivolol also reduced levels of malondialdehyde, tumor necrosis factor-α, and nitrite in diabetes. Moreover, nebivolol increased the levels of superoxide dismutase and catalase in sciatic nerve homogenate of diabetic rats. Further, nebivolol exerted positive effects on lipid profile, sciatic nerve's morphological changes and nerve conduction velocity in diabetic rats. Results of the present study suggest the neuroprotective effect of nebivolol through its antioxidant, nitric oxide-potentiating, and antihyperlipidemic activity.

Development and evaluation of novel biodegradable chitosan based metformin intrapocket dental film for the management of periodontitis and alveolar bone loss in a rat model.

OBJECTIVE: The aim of this study was to develop a chitosan-metformin based intrapocket dental film (CMIDF) for applications in the treatment of periodontitis and alveolar bone loss in an rat model of periodontitis. DESIGN: CMIDF inserts were fabricated by the solvent casting technique. The fabricated inserts were evaluated for physical characteristics such as folding endurance, surface pH, mucoadhesive strength, metformin content uniformity, and release. X-ray diffraction analysis indicates no crystallinity of metformin in presence of chitosan which confirmed successful entrapment of metformin into the CMIDF. Fourier-transform infrared spectroscopy revealed stability of CMIDF and compatibility between metformin and chitosan. Periodontitis was induced by a combination of Porphyromonas gingivalis- lipopolysaccharide injections in combinations with ligatures around the mandibular first molar. We divided rats into 5 groups (8 rats/group): healthy, untreated periodontitis; periodontitis plus CMIDF-A (1.99±0.09mg metformin; total mass-4.01±0.05mg), periodontitis plus CMIDF-B (2.07±0.06mg metformin; total mass-7.56±0.09mg), and periodontitis plus chitosan film (7.61±0.08mg). After four weeks, mandibles were extracted to evaluate alveolar bone loss by micro-computerized tomography and histological techniques. RESULTS: Alveolar bone was intact in the healthy group. Local administration of CMIDF resulted in significant improvements in the alveolar bone properties when compared to the untreated periodontitis group. The study reported here demonstrates that novel CMIDF showed good antibacterial activity and effectively reduced alveolar bone destruction in a rat model of experimental periodontitis. CONCLUSIONS: Novel CMIDF showed good antibacterial activity and improved alveolar bone properties in a rat model.

Location and Number of Astrocytes Determine Dopaminergic Neuron Survival and Function Under 6-OHDA Stress Mediated Through Differential BDNF Release.

While astrocytes throughout the CNS share many common traits, they exhibit significant differences in function and number among brain regions. The aim of the present study is to assess the effect of region-specificity and number of astrocytes on the survival of dopaminergic neurons under stress, and to understand the possible mechanism by which these astrocytes extend neuroprotection to dopaminergic neurons. Purified astrocytes obtained from forebrain, midbrain, and hindbrain region were characterized through FACS and immunofluorescence. Co-culture experiments (using trans-wells) were then performed to measure the effect of region-specificities and numbers of astrocytes on primary midbrain culture under 6-OHDA stress. Cell survival augmented with an increase in astrocyte seeding number and total cell survival was comparable among the different region-specific astrocytes for all numbers. However, striking differences were observed in dopaminergic neuronal (TH) cell survival in the presence of midbrain astrocytes in comparison to forebrain and hindbrain astrocytes at all seeding numbers. At 75 µM 6-OHDA insult, while cell survival was comparable in purified astrocytes from the different brain regions, a distinct increase in BDNF secretion (significantly higher than its constitutive release) was noted for midbrain astrocytes compared to forebrain and hindbrain astrocytes. The TH immunopositive population decreased when TrkB inhibitor was added to the co-culture under 6-OHDA toxicity, suggesting that BDNF released by co-cultured astrocytes plays a key role in the survival of dopaminergic neurons. This BDNF release decreased in presence of NO inhibitor and increased in the presence of NO donor (DETA/NO). We conclude that the BDNF released from astrocytes under 6-OHDA toxicity is mediated through NO release through both autocrine and paracrine signaling, and this BDNF release is primarily responsible for the differential effect of region-specific astrocytes on TH neuron survival under these conditions.

Effect of locally administered novel biodegradable chitosan based risedronate/zinc-hydroxyapatite intra-pocket dental film on alveolar bone density in rat model of periodontitis.

The aim of this study was to develop a chitosan-based risedronate/zinc-hydroxyapatite intrapocket dental film (CRZHDF) for applications in the treatment of alveolar bone loss in an animal model of periodontitis. The physical characteristics (folding endurance, pH, mucoadhesive strength, risedronate content and release) of CRZHDF, exhibited results within the limit. X-ray diffraction analysis indicates reduced or disappeared crystallinity of risedronate and zinc-hydroxyapatite in presence of chitosan. Further, FTIR studies revealed stability of CRZHDF and compatibility between risedronate, zinc-hydroxyapatite and chitosan. Periodontitis was induced by Porphyromonas gingivalis-lipopolysaccharide injections around the mandibular first molar. We divided rats into 5 groups (12 rats/group): healthy, untreated periodontitis; periodontitis plus CRZHDF-A, periodontitis plus CRZHDF-B, and periodontitis plus chitosan film. After four weeks, blood samples and mandibles were obtained for biochemical, radiographic and histological analysis. Bone specific alkaline phosphatise activity and tartrate resistant acid phosphatase 5b was statistically lower in CRZHDF-A and CRZHDF-B groups as compared to the untreated periodontitis group (p < 0.0001). The expression of osteocalcin was statistically higher in CRZHDF-A and CRZHDF-B groups as compared to the untreated periodontitis group (p < 0.0001). Alveolar bone was intact in the healthy group. Local administration of CRZHDF resulted in significant improvements in the mesial and distal periodontal bone support (MPBS and DPBS, respectively) proportions (%), bone mineral density, and also reversed alveolar bone resorption when compared to the untreated periodontitis group (p < 0.001). The study reported here reveals that novel CRZHDF treatment effectively reduced alveolar bone destruction and contributes to periodontal healing in a rat model of experimental periodontitis.

Functional recovery upon human dental pulp stem cell transplantation in a diabetic neuropathy rat model.

Diabetic neuropathy (DN) is among the most debilitating complications of diabetes. Here, we investigated the effects of human dental pulp stem cell (DPSC) transplantation in Streptozotocin (STZ)-induced neuropathic rats. Six weeks after STZ injection, DPSCs were transplanted through two routes, intravenous (IV) or intramuscular (IM), in single or two repeat doses. Two weeks after transplantation, a significant improvement in hyperalgesia, grip-strength, motor coordination and nerve conduction velocity was observed in comparison with controls. A rapid improvement in neuropathic symptoms was observed for a single dose of DPSC IV; however, repeat dose of DPSC IV did not bring about added improvement. A single dose of DPSC IM showed steady improvement, and further recovery continued upon repeat IM administration. DPSC single dose IV showed greater improvement than DPSC single dose IM, but IM transplantation brought about better improvement in body weight. A marked reduction in tumor necrosis factor (TNF) α and C-reactive protein (CRP) levels was observed in the blood plasma for all treated groups, as compared with controls. With respect to inflammatory cytokines, repeat dose of DPSC IM showed further improvement, suggesting that a repeat dose is required to maintain the improved inflammatory state. Gene expression of inflammatory markers in liver confirmed amelioration in inflammation. Arachidonic acid level was unaffected by IV DPSC transplantation but showed noticeable increase through IM administration of a repeat dose. These results suggest that DPSC transplantation through both routes and dosage was beneficial for the retrieval of neuropathic parameters of DN; transplantation via the IM route with repeat dose was the most effective.

Inhibitors of soluble epoxide hydrolase minimize ischemia-reperfusion-induced cardiac damage in normal, hypertensive, and diabetic rats.

AIM: We designed a study to evaluate the cardioprotective effect of two soluble epoxide hydrolase (sEH) inhibitors, 1-(1-propanoylpiperidin-4-yl)-3-(4-trifluoromethoxy)phenyl)urea (TPPU) and trans-4-{4-[3-(4-trifluoromethoxyphenyl)-ureido]cyclohexyloxy}benzoic acid (t-TUCB), in ischemia-reperfusion (IR) model. METHODS: Cardioprotective effects of the sEH inhibitors were evaluated against IR-induced myocardial damage in hearts from normal, hypertensive, and diabetic rats using Langendorff's apparatus. In addition, the effect of sEH inhibitors on endothelial function was evaluated in vitro and ex vivo using isolated rat thoracic aorta. RESULTS: Ischemia-reperfusion (IR) increased the myocardial damage in hearts from normal rats. IR-induced myocardial damage was augmented in hearts isolated from hypertensive and diabetic rats. Myocardial damage as evident from increase in the activities of lactate dehydrogenase (LDH) and creatine kinase-MB (CK-MB) in heart perfusate was associated with significant decrease in the heart rate and developed tension, and increase in the resting tension in isolated heart. Both sEH inhibitors protected the heart in normal, hypertensive, and diabetic rats subjected to IR injury. The sEH inhibitor t-TUCB relaxed phenylephrine precontracted aorta from normal rats. Relaxant effect of acetylcholine (ACh) was reduced in aortas from diabetic and hypertensive rats compared to normal rats. Pretreatment of sEH inhibitors to diabetic and hypertensive rats increased relaxant effect of ACh on aortas isolated from these rats. CONCLUSIONS: Prophylactic treatment with sEH inhibitors decreased myocardial damage due to IR, hypertension and diabetes, and decreased endothelial dysfunction created by diabetes and hypertension. Therefore, inhibitors of sEH are useful probes to study cardiovascular pathology, and inhibition of the sEH is a potential approach in the management of IR-induced cardiac damage and endothelial dysfunction-related cardiovascular disorders.

Zolendronic Acid-Conjugated PLGA Ultrasmall Nanoparticle Loaded with Methotrexate as a Supercarrier for Bone-Targeted Drug Delivery.

Drug delivery to deep-seated tissues such as bone has been a major complication till date. This preferential drug delivery is further important in targeting anti-tumour agents to bone metastasis owing to its complexity. The present study involves the formulation of PLGA nanoparticles and conjugation with zolendronic acid-a bisphosphonate which will anchor the nanosystem to bone due to its selective bone affinity. The conjugated nanosystem was characterized for particle size by TEM (average 36 nm) and morphology by AFM depicting surface irregularities due to ZOL conjugation on the surface of nanoparticles. NMR spectral data also showed the involvement of terminal -OH group of PLGA in bond formation with ZOL. Bone localization studies showed higher accumulation of the ZOL-conjugated nanosystem in bone than non-conjugated nanoparticles. This was confirmed with bone mineral affinity and specificity assay wherein the conjugated nanosystem was found to selectively bind to hydroxyapatite in comparison to other bone minerals. The biodistribution studies depicted that the conjugated nanosystem was selectively targeted to the bone area with concentrations of methotrexate reaching up to 127.4 ± 1.41 µg in 1 h. Hence, this multipronged approach using (1) ultrasmall size of nanoparticles, (2) bone selective polymer and (3) suitable bone-targeting agent resulted in mutual synergism for the specific delivery of the anti-tumour agent to the bone.

Novel therapeutic intervention for osteoporosis prepared with strontium hydroxyapatite and zoledronic acid: In vitro and pharmacodynamic evaluation.

Osteoporosis therapeutics has been monopolized mainly by bisphosphonates, which are potent anti-osteoporotic drugs, while they do not promote bone formation or replenish the already resorbed bone. Although strontium substituted hydroxyapatite (SrHA) has been proclaimed to improve bone properties in an osteoporotic animal model, there is no published data on direct delivery of SrHA nanoparticles by bisphosphonate-like zoledronic acid (ZOL) to the bone. Therefore, this study was designed to investigate the potential of using SrHA/ZOL nanoparticle-based drug formulation in an ovariectomized rat model of postmenopausal osteoporosis. SrHA and SrHA/ZOL nanoparticles were prepared and characterized by field-emission scanning electron microscopy (FESEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). Twelve weeks after ovariectomy, rats were treated with either single intravenous dose of SrHA/ZOL (100, 50 or 25µg/kg); ZOL (100µg/kg); or SrHA (100µg/kg). Saline-treated OVX and SHAM-OVX groups served as controls. The energy-dispersive X-ray (EDX) microanalysis of bone specimen obtained from SrHA/ZOL groups yielded range between 64.3±6.7 to 66.9±6.8 of calcium weight (wt) % and 1.64±0.6 to 1.74±0.8 of calcium/phosphorus (Ca/P) ratio which was significantly higher when compared with 39.7±9.3 calcium and 1.30±0.2 Ca/P ratio for OVX group. Moreover, the strontium wt% in SrHA/ZOL group (between 3.1±0.5 and 6.8±0.4) was significantly higher than SrHA group (1.8±0.9). These results confirmed targeted delivery of SrHA nanoparticles by ZOL to the bone. Therapy with SrHA/ZOL showed significant improvements in trabecular bone microarchitecture and mechanical strength as compared to ZOL or SrHA (p<0.05). Moreover, treatment with SrHA/ZOL significantly precluded an increase in serum bone-specific alkaline phosphatase and tartrate-resistant acid phosphatase than either ZOL or SrHA (p<0.05). These results strongly implicate that SrHA/ZOL nanoparticle-based drug formulation showed better efficacy at a much lower dose of ZOL. SrHA/ZOL drug formulation has a therapeutic advantage over ZOL or SrHA monotherapy for experimental osteoporosis.

Therapeutic insight into molsidomine, a nitric oxide donor in streptozotocin-induced diabetic nephropathy in rats.

BACKGROUND: Diabetes-induced oxidative stress and hypertension play a major role in the development of nephropathy. Hence, the present study was undertaken to evaluate the protective effects of molsidomine, a nitric oxide donor in streptozotocin (STZ)-induced diabetic nephropathy (DN) in rats. MATERIALS AND METHODS: Type 1 diabetes was induced through a single dose of STZ (52 mg/kg, i.p.) in male Wistar rats and then treated with molsidomine (5 and 10 mg/kg; p.o.) for 8 weeks. Physical parameters, vital and renal function test including blood glucose, albuminuria, blood urine nitrogen, serum creatinine, and kidney index were determined. Oxidative stress and lipid peroxidation were assessed in the kidney homogenate by means of antioxidant enzymes and malondialdehyde levels. RESULTS: DN rats exhibited a significant renal dysfunction with a reduction in body weight, excessive oxidative stress, and pathological changes. Molsidomine treatment significantly improved vital sign, renal functions, and oxidative stress in DN rats in a dose-dependent manner. The protective effect of molsidomine was also substantiated by pathological changes in the architect of the kidney. CONCLUSION: Molsidomine shows a significant beneficial effect in Type 1 DN in rats.

Risedronate/zinc-hydroxyapatite based nanomedicine for osteoporosis.

Targeting of superior osteogenic drugs to bone is an ideal approach for treatment of osteoporosis. Here, we investigated the potential of using risedronate/zinc-hydroxyapatite (ZnHA) nanoparticles based formulation in a rat model of experimental osteoporosis. Risedronate, a targeting moiety that has a strong affinity for bone, was loaded to ZnHA nanoparticles by adsorption method. Prepared risedronate/ZnHA drug formulation was characterized by field-emission scanning electron microscopy, X-ray diffraction analysis and fourier transform infrared spectroscopy. In vivo performance of the prepared risedronate/ZnHA nanoparticles was tested in an experimental model of postmenopausal osteoporosis. Therapy with risedronate/ZnHA drug formulation prevented increase in serum levels of bone-specific alkaline phosphatase and tartrate-resistant acid phosphatase 5b better than risedronate/HA or risedronate. With respect to improvement in the mechanical strength of the femoral mid-shaft and correction of increase in urine calcium and creatinine levels, the therapy with risedronate/ZnHA drug formulation was more effective than risedronate/HA or risedronate therapy. Moreover, risedronate/ZnHA drug therapy preserved the cortical and trabecular bone microarchitecture better than risedronate/HA or risedronate therapy. Furthermore, risedronate/ZnHA drug formulation showed higher values of calcium/phosphorous ratio and zinc content. The results strongly implicate that risedronate/ZnHA drug formulation has a therapeutic advantage over risedronate or risedronate/HA therapy for the treatment of osteoporosis.

Antioxidant Potential and Ability of Phloroglucinol to Decrease Formation of Advanced Glycation End Products Increase Efficacy of Sildenafil in Diabetes-Induced Sexual Dysfunction of Rats.

INTRODUCTION: Diabetes-induced sexual dysfunction is associated with an increase in oxidative stress. Scavengers of reactive oxygen species (ROS) have been shown to reduce oxidative stress and aid in the management of sexual dysfunction in diabetes. AIM: The aim of the study was to test the hypothesis that antioxidant, which scavenge ROS and reduce formation of advanced glycation end products (AGEs), can potentiate efficacy of phosphodiesterase type 5 inhibitors in diabetes-induced sexual dysfunction that is associated with oxidative stress. MATERIALS AND METHODS: Effect of phloroglucinol and sildenafil on serum glucose level, sexual function, penile smooth muscle : collagen ratio, and phenylephrine precontracted corpus cavernosum smooth muscle (CCSM) was studied. The ability of phloroglucinol to reduce the formation of AGEs and its ability to scavenge 2,2-diphenyl-1-picrylhydrazyl (DPPH) and nitric oxide (NO) was also evaluated. MAIN OUTCOME MEASURES: Antioxidant potential of phloroglucinol was studied in addition to its effect on diabetes-induced sexual dysfunction in presence and absence of sildenafil. RESULTS: Phloroglucinol (50 mg/kg, p.o.) significantly decreased serum glucose level and increased sexual function in streptozotocin-induced diabetic rats when compared with diabetic control rats. Sildenafil (5 mg/kg, p.o.) had no effect on glycemia but significantly increased sexual function of diabetic rats. Coadministration of phloroglucinol increased the efficacy of sildenafil by improving sexual function. Treatment of diabetic rats with phloroglucinol + sildenafil maintained smooth muscle : collagen levels similar to that of normal rat penile tissue. Phloroglucinol decreased formation of AGEs and significantly scavenged DPPH radical activity in vitro. Sildenafil relaxed isolated CCSM of normal rat and diabetic rat significantly, but phloroglucinol did not show any significant effect. Phloroglucinol also inhibited human CYP3A4 enzyme activity in vitro. CONCLUSION: Phloroglucinol coadministration increases efficacy of sildenafil in diabetes-induced sexual dysfunction. However, further studies are required to ascertain the benefits of phloroglucinol owing to its undesirable CYP3A4 inhibition activity.

Efeitos da terapia combinada com ácido zoledrônico e propranolol na resistência mecânica em um modelo de rato com osteoporose por desuso / Effect of combined treatment with zoledronic acid and propranolol on mechanical strength in an rat model of disuse osteoporosis

Resumo Objetivos: Investigar os efeitos aditivos do agente antirreabsorção ácido zoledrônico (ZOL), isolado e em combinação ao propranolol (PRO), em um modelo de rato com osteoporose por desuso. Métodos: Usou-se um modelo de pata traseira direita de rato privada de descarga de peso para estudar as consequências da falta de descarga de peso sobre o esqueleto durante várias condições, como missões espaciais e repouso prolongado no leito em idosos. Ratos Wistar machos de três meses de idade foram submetidos à imobilização da pata traseira direita (IPTD) por 10 semanas para induzir à osteopenia; em seguida, foram divididos aleatoriamente em quatro grupos: 1 – IPTD para controle positivo; 2 – IPTD mais ZOL (50 μg/kg, dose única intravenosa); 3 – IPTD mais PRO (0,1 mg/kg, via subcutânea, cinco dias na semana); 4 – IPTD mais PRO (0,1 mg/kg, via subcutânea, cinco dias na semana) mais ZOL (50 μg/kg, dose única intravenosa) por outras 10 semanas. Um grupo de ratos não imobilizados foi usado como controle negativo. No fim do tratamento, os fêmures foram removidos e testaram-se a porosidade do osso e suas propriedades mecânicas, além do peso seco e das cinzas do osso. Resultados: No que diz respeito à melhoria da resistência mecânica da diáfise femoral média, a terapia combinada com ZOL mais PRO foi mais eficaz do que a monoterapia com ZOL ou PRO. Além disso, a terapia combinada com ZOL mais PRO foi mais eficaz na melhoria do peso seco do osso e preservou melhor a porosidade do osso cortical do que a monoterapia com ZOL ou PRO em ratos submetidos à imobilização da pata traseira direita. Conclusões: Esses dados sugerem que a terapia combinada com ZOL mais PRO deve ser recomendada para o tratamento da osteoporose por desuso.

Abstract Objectives: A model that uses right hind-limb unloading of rats is used to study the consequences of skeletal unloading during various conditions like space flights and prolonged bed rest in elderly. This study was aimed to investigate the additive effects of antiresorptive agent zoledronic acid (ZOL), alone and in combination with propranolol (PRO) in a rat model of disuse osteoporosis. Methods: In the present study, 3-month-old male Wistar rats had their right hind-limb immobilized (RHLI) for 10 weeks to induce osteopenia, then were randomized into four groups: (1) RHLI positive control, (2) RHLI plus ZOL (50 μg/kg, i.v. single dose), (3) RHLI plus PRO (0.1 mg/kg, s.c. 5 days per week), (4) RHLI plus PRO (0.1 mg/kg, s.c. 5 days per week) plus ZOL (50 μg/kg, i.v. single dose) for another 10 weeks. One group of non-immobilized rats was used as negative control. At the end of treatment, the femurs were removed and tested for bone porosity, bone mechanical properties, and bone dry and ash weight. Results: With respect to improvement in the mechanical strength of the femoral mid-shaft, the combination treatment with ZOL plus PRO was more effective than ZOL or PRO monotherapy. Moreover, combination therapy using ZOL plus PRO was more effective in improving dry bone weight and preserved the cortical bone porosity better than monotherapy using ZOL or PRO in RHLI rats. Conclusions: These data suggest that this combined treatment with ZOL plus PRO should be recommended for the treatment of disuse osteoporosis.

Efeito combinado do ácido zoledrônico e do alfacalcidol no tratamento da osteoporose por desuso em ratos / Additive effect of zoledronic acid and alfacalcidol in the treatment of disuse osteoporosis in rats

Objetivos: O desuso pelo repouso no leito, pela imobilização de membros ou por missões espaciais provoca a perda óssea rápida. Fez-se este estudo para investigar os efeitos terapêuticos do ácido zoledrônico (ZOL), isoladamente e em combinação ao alfacalcidol (ALF), em um modelo de rato com osteoporose por desuso. Métodos: Ratos Wistar machos de três meses foram submetidos à imobilização da pata traseira direita (IPTD) por 10 semanas para induzir a osteopenia; em seguida, foram divididos em quatro grupos: 1 – IPTD para controle positivo; 2 – IPTD mais ZOL (50 µg/kg, dose única intravenosa); 3 – IPTD mais ALF (0,5 µg/kg, via oral diariamente); 4 – IPTD mais ALF (0,5 µg/kg, via oral diariamente) mais ZOL (50 µg/kg, dose única intravenosa) por outras 10 semanas. Um grupo de ratos não imobilizados foi usado como controle negativo. No fim do tratamento, os fêmures foram removidos e testaram-se a porosidade do osso e suas propriedades mecânicas, além do peso seco e das cinzas do osso. Resultados: A terapia combinada com ZOL mais ALF foi mais eficaz em reduzir a porosidade do osso do que a monoterapia com um dos fármacos administrado isoladamente em ratos submetidos à IPTD. No que diz respeito à melhoria da resistência mecânica da diáfise femoral média, o tratamento combinado com ZOL mais ALF foi mais eficaz do que a monoterapia com um dos fármacos administrado isoladamente. Além disso, a terapia combinada com ZOL mais ALF foi mais eficaz na melhoria do peso seco e das cinzas do osso do que a monoterapia com ZOL ou ALF em ratos submetidos à IPTD. Conclusões: Esses dados sugerem que a terapia combinada com ZOL mais ALF representa uma opção terapêutica potencialmente útil para o tratamento da osteoporose por desuso. .

Objectives: Disuse by bed rest, limb immobilization or space flight causes rapid bone loss. We conducted the present study to investigate the therapeutic effects of zoledronic acid (ZOL), alone and in combination with alfacalcidol (ALF) in a rat model of disuse osteoporosis. Methods: In the present study, 3-month-old male Wistar rats had their right hind-limb immobilized (RHLI) for 10 weeks to induce osteopenia, then were divided into four groups: 1 – RHLI positive control; 2 – RHLI plus ZOL (50 µg/kg, i.v. single dose); 3 – RHLI plus ALF (0.5 µg/kg, oral gauge daily); 4 – RHLI plus ALF (0.5 µg/kg, oral gauge daily) plus ZOL (50 µg/kg, i.v. single dose) for another 10 weeks. One group of non-immobilized rats was used as negative control. At the end of the treatment, the femurs were removed and tested for bone porosity, bone mechanical properties, and bone dry and ash weight. Results: Combination therapy with ZOL plus ALF was more effective in decreasing bone porosity than each drug administered as monotherapy in RHLI rats. With respect to improvement in the mechanical strength of the femoral mid-shaft, the combination treatment of ZOL plus ALF was more effective than each drug administered as a monotherapy. Moreover, combination therapy using ZOL plus ALF was more effective in improving dry bone and ash weight, than single-drug therapy using ZOL or ALF in RHLI rats. Conclusions: These data suggest that combination therapy with ZOL plus ALF represents a potentially useful therapeutic option for the treatment of disuse osteoporosis. .