Effects of Azadirachta indica on neuropathic pain induced by chronic constriction injury to sciatic nerve of Wistar rat.

Objective: The research was designed to assess the consequences of Azadirachta indica aqueous leaf extract (AILE) on neuropathic pain in Wister rats and the role of the ATP-dependent potassium channel (KATP) as an underlying mechanism. Materials and Methods: This experimental layout was conducted on Wistar rats (n = 120) having 150 to 200 gm of body weight. On the foundation of the experimental design, rats were divided into group I (normal saline, 5 ml/kg/body weight) and group II (sham surgery and treatment with NS), group III [chronic constriction injury (CCI) in the sciatic nerve; and treated with NS], group IV (CCI and treated with AILE 400 mg/kg body weight), Group V (CCI, pretreated with Glibenclamide 15 mg/kg followed by treated with AILE 400 mg/kg). All the treatments were given once daily for a consecutive 21 days via the oral route, except Glibenclamide. Glibenclamide was given once through the intraperitoneal route on the day of the experiment. Results: Based on the neuropathic pain evaluation test, all groups were again sub-divided into subgroup "a" (walking tract analysis), "b" (cold tail immersion test), "c" (Von Frey test), and "d" (hot plate test). AILE showed a significantly higher sciatic functional index (p < 0.05) in walking track analysis, tail flick latency (p ≤ 0.05) in the cold tail immersion test, and paw withdrawal threshold (p ≤ 0.05) in the Von Frey test compared to CCI control. In addition, a nonsignificant difference in all these above-mentioned variables between the rats with CCI plus AILE and the CCI plus AILE plus glibenclamide group indicated that the KATP channel was not involved in the beneficial analgesic effects of AILE. Conclusions: The outcome of the present study indicates that AILE prevented worsening of neuropathic pain after chronic constriction injury in the sciatic nerve of Wistar rats in which the KATP channel was not involved.

Effects of Spirulina platensis on pain and inflammation in long Evans rats.

Spirulina platensis (S. platensis) is a traditional herb that has been reported to have a lot of medicinal values. This study was designed to observe the effects of S. platensis on different types of pain and inflammation in comparison to diclofenac sodium. Three groups of Long Evans rats (n=21in each group) of both sexes were used. Group I was treated orally with normal saline (5ml/kg/day for 21 days), group II was treated with diclofenac sodium (10mg/kg/day for 7 days) and group III with S. platensis (400mg/kg/day for 21 days). Effects of S. platensis on pain were assessed by tail immersion test (nociception pain), formalin test (nociception and inflammatory pain), Von Frey test (neuropathic pain) and the effects on inflammation were assessed by formalin induced paw edema test. Macroscopic and microscopic examinations of rats' stomachs were done to observe anti-ulcerogenic effect. S. platensis showed potent (statistically significant) analgesic effects in all 3 models of pain (tail immersion test, formalin tests, Von Frey test) as well as anti-inflammatory effects in formalin induced paw edema test. Interestingly, anti-ulcerogenic effect of S. platensis was almost similar to that of negative control and was significantly different with positive control. In conclusion, these data indicate that S. platensis possess analgesic, anti-inflammatory and anti-ulcerogenic potential.

Reno-pancreas protective effects of Spirulina platensis in alloxan induced diabetic rats.

A large variety of herbal elements are employed in the treatment of diabetes for their better efficacy and safety compare to synthetic drugs. In this experiment Spirulina platensis was used to evaluate the antidiabetic, kidney & pancreas injury protective potential in alloxan induced diabetic rats. Male Long Evans rats having six weeks of age were used for the experiment. Diabetes was induced by intraperitoneal injection of alloxan @ 150 mg/kg and experiment was carried out for a period of six weeks. The study was conducted by dividing the animal into three groups (n=7 rats in each group) indicated as with Group-A (healthy control); Group-B (diabetic control); Group-C (Diabetic rats treated with Spirulina platensis @ 400 mg/kg). Spirulina platensis reduced blood glucose significantly (P<0.01) and improved the body weight losses significantly (P<0.05) compared to diabetic rats after six weeks treatment. The histopathological alteration was observed in the kidney of diabetic rats which was characterized by glomerular hypertrophy, tubular necrosis and interstitial fibrosis. Marked improvements in the histopathological change were noticed in the kidneys of diabetic rats treated with Spirulina platensis. Pancreatic injury was produced by alloxan induction in rats characterized by destruction of the pancreatic ß cells mostly in the central portion of the islets of langerhans and lymphocytic infiltrations, atrophy, and interstitial fibrosis, which were suppressed by Spirulina platensis. In addition, alloxan induced diabetic rats showed increased plasma lipid peroxidase level which was ameliorated by Spirulina platensis treatment. Along with previous report the anticipated results would concluded that Spirulina platensis having antioxidant compounds could protect renal tissues damage, stimulate regeneration and reactivation of pancreatic ß- cells in alloxan induced diabetic rats.

Antinociceptive and anti-inflammatory activities of the essential oil of Nepeta crispa Willd. in experimental rat models.

This study was conducted to evaluate the antinociceptive and anti-inflammatory activities of the essential oil of Nepeta crispa. The study was done using the tail-flick and formalin test pain models and the paw oedema model of inflammation. Male Wistar rats were used as the animal model. The essential oil dose-dependently produced analgesia in the acute pain models, including the tail-flick (p < 0.001) and the first phase of the formalin test (p < 0.01). In the late phase of the formalin test, as a model of chronic pain, the essential oil significantly reduced the pain-induced behaviour (p < 0.01). Nepeta crispa essential oil caused potent anti-inflammatory effects in the formalin-induced paw inflammation model and significantly reduced the paw oedema in all applied doses (p < 0.01). Its effects on pain in both the acute and chronic pain models and its anti-inflammatory effect suggest both central and peripheral mechanisms of action for the essential oil obtained from N. crispa.

Evaluation of the antinociceptive and anti-inflammatory effects of essential oil of Nepeta pogonosperma Jamzad et Assadi in rats.

UNLABELLED: BACKGROUND AND THE PURPOSE OF STUDY: Concerning the different effects of essential oils from Nepeta genus on the central nervous system including pain killing effect, this study was designed to evaluate the antinociceptive and anti-inflammatory effects of essential oil of Nepeta pogonosperma Jamzad et Assadi (NP), a recently identified species. METHODS: Air-dried aerial parts of NP were hydrodistillated and GC-MS analysis of obtained essential oil was conducted. Total 24 male Wister rats weighing 225 ± 25 gm were studied. Essential oil of NP was administered intraperitoneally at the doses of 50 mg/kg, 100 mg/kg and 200 mg/kg for the experimental groups. Control rats received equal volume (2 ml/kg) of normal saline. Antinociception was assessed by tail flick test (after 30 minutes) and formalin test (for further 60 minutes). Then the animal was sacrificed and the paw edema was measured using a water plethysmometer. RESULTS: 4aα,7α,7aß-nepetalactone and 1,8-cineole were found as the main concentrated components of NP essential oil. All the doses of NP showed antinociception. NP 200 mg/kg reduced the pain sensation in tail flick (p <0.01) and formalin test (p <0.001 in both phases). In paw edema test, NP 100 and 200 mg/kg significantly reduced the inflammation (p <0.01 and p <0.05). CONCLUSION: This study reveals that the essential oil of NP may minimize both the acute and chronic forms of nociception and may have potent role against inflammation, but the dose should be maintained precisely to obtain the intended effect.