The Effect of Indigofera tinctoria Extract on Cdk5 Expression and Signs of Inflammation in A Chronic Pain Rat Model

Abstract

Chronic pain is a challenging case that requires efforts to find effective drugs with minimal side effects. In the last decade, Cdk5 has become a potential target of chronic pain treatment.  Indigofera tinctoria is a plant that grows abundantly in Indonesia and has been used for various purposes. This plant is proven to contain indirubin which was proven as a Cdk5 (Cyclin dependent kinases 5) inhibitor. The objective of this research is to analyze the effect of Indigofera tinctoria in a chronic pain model. This research was conducted on 35 rats divided into 5 groups. CFA (Complete Freud’s Adjuvant) solution was injected into the right plantar area to make a chronic pain model. Indigofera tinctoria extract was given orally in 200 mg/KgBW (D1 group), 300 mg/KgBW (D2 group), and 400 mg/KgBW (D3 group) doses. Treatment was given for 7 days after the sign of chronic inflammation were detected (28 days after CFA induction). The analgesic effect was determined by pain latency on the hotplate, while the anti-inflammatory effect was evaluated by measuring the hind paw volume. The Cdk5 expression was detected at the dorsal root ganglia by immunohistochemistry method. The mean pain latency value of the D2 and D3 groups was greater than that of the other groups. The inflammatory sign in the treatment group was smaller and differs significantly from the positive control group. Cdk5 expression was not statistically different, however, the treatment group showed a lower Cdk5 expression. Indigofera extract has potential analgesic, anti-inflammatory, and Cdk5 inhibitory effects.