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.