Investigating the effects of curcumin on peripheral nerves in the statin-administered rats

Objective: Cardiovascular diseases (CVDs) are one of the leading cause of mortality in humans, and about 1/3 of deaths worldwide occur due to CVDs. Statins are a class of cholesterol‐lowering drugs, commonly used to prevent or treat CVDs. Safe and tolerable long-term use of statins is important for chronic hypercholesterolemia. Curcumin is a polyphenolic compound which has neuroprotective, anti-inflammatory, and anticancer properties. This study aimed to investigate curcumin's possible protective effects and mechanism in polyneuropathy, which is expected to be induced by the statin administration in rats. Material and Methods: Thirty-eight male Wistar Albino rats were divided into four groups: i) statin group (40 mg/kg atorvastatin); ii) statin (40 mg/kg atorvastatin) + curcumin (400 mg/kg) group; iii) curcumin group (400 mg/kg) group; and iv) control group (saline). Atorvastatin and curcumin were given via intragastric route for 30 days. At the end of the experiment, nerve conduction velocity, Na+- K+ ATPase, total cholesterol, total oxidant and antioxidant capacity, TNF-α and, IL-6 levels were determined. Results: Atorvastatin reduced NCV, compared with the other groups (p<0.0001). In addition, Na+- K+ ATPase activity was lower in the statin group than in the control and curcumin groups (p=0.001). Atorvastatin increased TNF-α levels (p=0.014) but did not affect on IL-6 levels (p=0.239). While the total oxidant status was not different between groups (p=0.604), the total antioxidant status increased in the atorvastatin+curcumin group (p=0.002) compared to the other groups. When sciatic nerve were examined, the myelin sheath was determined to be irregular and fragmented, accompanied by vacuolation. Conclusion: These findings suggest that statins may potentially induce polyneuropathy by decreasing Na+- K+ ATPase activity. Notably, curcumin administration ameliorates the reduced NCV and Na+- K+ ATPase activity. Curcumin intake may have protective effects on peripheral neuropathy that might occur during statin treatment.