The Effect of Intrathecal Administration of Vitamin K2 on Inflammatory Rat Paw Edema Induced by Formalin

vitamin K2 involves one of the vitamin K derivatives which is synthesized by intestinal bacteria. A great number of studies have demonstrated the presence of high concentration of vitamin K2 as well as its important functions in the brain. Vitamin K2 is capable to inhibit many inflammatory mediators in different diseases. Therefore, this study intended to investigate the effect of vitamin K2 at the level of spinal cord in inflammatory paw edema induced by formalin.

In this research study, male Wistar rats (200-250g), except those of the control group, after recovery from cannulation surgery for intrathecal administration (i.t.), were classified into four groups including sham (DMSO), 2µg/10µl vitamin K2, 10µg/10µl vitamin K2 and 20µg/10µl vitamin K2. In each group, inflammatory edema volume caused by sub plantar injection of formalin (0.05 ml, 2.5%) was measured after one hour using plethysmometric method.

The study results indicated that I.t injection of vitamin K2 reduced formalin induced inflammatory paw edema significantly (P<0.01). In addition, in comparison with the other concentrations, the lowest concentration of vitamin K2 (2µg/10µl) demonstrated the highest decrease in inflammatory paw edema volume induced by formalin (P<0.05).

Vitamin K2 can reduce the edema volume induced by formalin, probably by diminishing as well as inhibiting the activity of COX and synthesis of prostaglandins. Moreover, this effect on edema can be exerted via reducing free radicals such as ROS and NO followed by decreasing the release of inflammatory and pro-inflammatory mediators in the spinal cord and thus in the peripheral.