Objective: To optimize the dosage of histamine and 4-aminopyridine (4-AP) combined modeling by star point design-effect plane method, aiming to establish a new type of guinea pig pruritus animal model.
Method: The experiment was arranged with a star point design. Each group was injected with 0.5 mL of different itching agents under the skin of the depilation site. The scratch latency and the number of scratches within 30 minutes of the guinea pig were recorded, and the best itching formula was selected by a comprehensive score method. The guinea pig model was evaluated by observing the behavioral changes of guinea pigs and measuring the levels of histamine and interleukin-6 (IL-6) in the blood.
Results: Behavioral experiments found that the number of scratches in the combined group within 30 minutes was significantly higher than that of the histamine group and 4-AP group (P<0.01), and the scratching latency was significantly shorter (P<0.01). The number of scratches in the 4-AP group within 30 minutes was significantly higher than that in the histamine group (P<0.01). Compared with the control group, the serum histamine concentration of guinea pigs in the combination group and histamine group was significantly increased (P<0.05 or P<0.01), but the degree of increase in the combination group was lower than that in the histamine group (P<0.05); and Compared with the control group, the serum IL-6 concentration of the histamine group, 4-AP group and the combination group were significantly increased (P<0.01 or P<0.05), and the combination group was significantly higher than the histamine group and 4- AP group. Pathological examination showed that each model group had different degrees of inflammatory cell proliferation, and the combination group had a more obvious response.
Conclusion: The optimized formula (combined group) model in this experiment is easy to implement and has good repeatability.