Protective effect of oryzanol isolated from crude rice bran oil in experimental model of diabetic neuropathy

Abstract

Several studies have implicated the involvement of poor glycemic control and oxidative/nitrosative stress in the development of diabetic neuropathic pain, an important microvascular complication affecting more than 50% of diabetic patients. However, lack of understanding of the underlying etiology, development of tolerance, inadequate relief and possible toxicity associated with classical analgesics warrant the investigation of the novel agents. Therefore, the present study was carried out to investigate the effect of oryzanol (OZ), a commercially-important potent antioxidant component isolated from from crude rice bran oil (cRBO), in streptozotocin (STZ)-induced diabetic neuropathy in rats. After eight weeks, diabetic rats developed neuropathy which was evident from decreased tail-flick latency (thermal hyperalgesia) and increased nociceptive behavior during the formalin test. This was accompanied by decreased motor coordination based on the evaluation of neuromuscular strength. Na + K + ATPase, a biochemical marker associated with the development of diabetic neuropathy, was significantly inhibited in the sciatic nerve of diabetic animals. The activities of antioxidant enzymes and lipid peroxidation levels were significantly elevated in diabetic rats, indicating the involvement of oxidative stress in diabetic neuropathy. Chronic treatment with oryzanol (OZ) (50 and 100 mg/kg) per oral (p.o.) and standard drug glibenclamide (Gl) (10 mg/ kg, p.o.) significantly attenuated the behavioral as well as biochemical changes associated with diabetic neuropathy. The findings provide experimental evidence to the protective effects of OZ on hyperglycemia-induced thermal hyperalgesia and oxidative stress which might be responsible for diabetes induced nerve damage.

Rice Bran Oil Compared to Atorvastatin for Treatment of Dyslipidemia in Patients with Type 2 Diabetes

“…Further TRF may be a useful antioxidant effectively caused decrease in glycosylated hemoglobin (HbA1C) in diabetic rats [39]. Furthermore, Oryzanol content in RBO can be considered as a novel antinociceptive agent and can be used as a possible therapeutic option in the treatment of neuropathic pain associated with diabetes mellitus [40].…”

Polyphenols for diabetes associated neuropathy: Pharmacological targets and clinical perspective

“…Treatment with curcumin also enhanced the anti-nociceptive activity in hot-plate and allodynia-tests in STZ-induced DNP via increasing pain threshold level compared to untreated diabetic rats [112]. Oryzanol and diosmin both significantly increased the tailflick latency in tail-immersion test and reduced the thermal hyperalgesia in STZ-induced diabetes [113]. In addition, diosmin treatment significantly improved shortening of time on walking function test in diabetic rats [114].…”

Hypolipidemic and Antioxidant Properties of Oryzanol Concentrate in Reducing Diabetic Nephropathy via SREBP1 Downregulation Rather than β‐Oxidation

“…This signifies both hyperlipidemia and hyperglycemia conditions helping in the enhanced expression of TGF‐β while treatment with OC reduced lipid profile as well as blood glucose that downregulated the expression of TGF‐β. Several reports claim the involvement of SREBP1 in the development of diabetic nephropathy . It has been confirmed in several diabetic models such as STZ, ob/ob , and OVE26 mice .…”