Study of the Involvement of the P2Y12 Receptor in Chronic Itching in Type 2 Diabetes Mellitus.

Itching is a common clinical symptom in diabetic patients. This research is to carry out experiments on the pathological changes in the P2Y12 receptor in type 2 diabetes mellitus complicated with chronic itching. Changes in body weight, fasting blood glucose (FBG), thermal hyperalgesia, cold hyperalgesia, spontaneous itching, and sciatic nerve conduction velocity were detected. The content of reactive oxygen species (ROS) in the dorsal root ganglion was detected by chemical fluorescence. The expression of the P2Y12 receptor, NLRP3, ASC, interleukin-1ß (IL-1ß), and IL-18 was detected by Western blotting, real-time quantitative PCR, immunofluorescence double labelling, and enzyme-linked immunosorbent assay. Itching and pain behaviours of the mice in the type 2 diabetes mellitus + itch group were significantly increased, and the expression of P2Y12 and NLRP3 as well as the content of ROS increased, and these changes were significantly reversed by treatment with P2Y12 short hairpin RNA (shRNA) or P2Y12 antagonist ticagrelor. Upregulated P2Y12 receptor expression after the activation of satellite glial cells contributes to the increase in ROS content in vivo, followed by NLRP3 inflammasome activation, increased inflammatory cytokine release, and damage to peripheral nerves, which leads to chronic itching. Treatment with P2Y12 shRNA or ticagrelor can inhibit these pathological changes, thus improving itching behaviour. Development mechanism of diabetes mellitus complicated with chronic itching. Notes: The upregulation of P2Y12 receptor expression and the activation of SGCs lead to the increase of ROS content in vivo, followed by the activation of NLRP3 inflammasome, the increase of inflammatory cytokine release, the abnormal excitation of DRG neurons, and the damage of peripheral nerves, resulting in chronic itching. P2Y12 receptor-related inflammatory injury involves chronic itching in type 2 diabetes mellitus. Treatment with P2Y12 receptor shRNA or P2Y12 antagonist ticagrelor can inhibit these pathological changes and improve itching behaviour.

A comparative study of two methods to construct allergic contact dermatitis in mice / 中国药理学通报

Abstract; Aim To explore the differences of 2,4-dinitrofluoro- benzene ( DNFB) -induced allergic contact demiatitis (ACD) models with different modeling cycles for the study of skin itch¬ing and inflammation, so as to provide reference and basis for the identification and selection of a more suitable animal model.Methods DNFB was used as a sensitizer, 0.5% DNFB was used to build a 2-week ACD model, and after 5-day sensitiza¬tion, the modeling site was administered once every other day and repeated four times.0.15% DNFB was used to build a 5- week ACD model, and after one week of treatment, DNFB was applied to the modeling site twice a week for four weeks.Behav¬ioral videos were recorded for 60 minutes alter each application of DNFB on the back of the neck for 24 hours.After modeling, Ig-K levels in serum were detected by KLISA, and the skin at the modeling site was stained for histopathology and observed.Results The entire modeling process of both modeled ACD mice was accompanied by severe scratching response after re¬peated skin exposure to DNFB, and the number of scratching significantly increased (P <0.01).Histopathological results showed epidermal thickening ( P < 0.01 ) , hyperkeratosis and inflammatory cell infiltration (P <0.01) in both modeling meth¬ods, and senmi Ig-F levels were significantly elevated ( P < 0.01).Conclusions The contact dennatitis model caused by DNFB is very stable, showing typical pruritus symptoms, severe dermatitis injury and inflammatory immune response, but the 5- week model may have more typical symptoms and allow enough time to observe the effect of the drug, which provides further ex¬perimental basis and evidence for pruritus and inflammation re¬lated drug research.