Effects Of Botulinum Toxin A On Plasma β-endorphin And Substance P In The Treatment Of Postherpetic Neuralgia And Its Curative Effect

Objective To investigate the influences of intradermal injection of botulinum toxin type A in the treatment of postherpetic neuralgia along with its effect on plasma β-endorphins and substance P.Methods Strictly following the criteria of exclusion and inclusion.Then collected and obtained the complete data for 58 patients who were diagnosed with PHN by the dermatology department of the affiliated hospital of Qinghai university from December 2017 to October 2019.According to the principle of random grouping,we divided those 58 patients with PHN into control group and observation group.Among all the groups,there are 30 patients in the control group and 28 patients in the observation group.All the 58 PHN patients were given gabapentin orally 3 days before treatment,and the treatment dose was maintained daily thereafter.For the observation group,we dissolved botulinum toxin type A(BTX-A)100 U in 4ml 0.9% NS,and injected BTX-A solution into the pain area by microdose multi-site subcutaneous injection.In terms of the control group,we injected 4ml 0.9% NS into the pain area in the same way.We recorded VAS scores for all PHN patients before treatment,at the same time,we extracted 5ml of fasting venous blood for centrifugation.Then VAS score was performed at 3d,2w and 8w after treatment and 5ml of venous fasting blood was extracted for centrifugation.Then we recorded the changes in VAS scores of PHN patients in the observation group and control group before and after treatment,and the plasma levels of evern-endorphin and substance P in the PHN patients in the observation group and control group were also measured before and after treatment.Results There were no significant differences in VAS score,β-endorphin content and substance P between the two groups before the treatment.3 days after treatment: VAS score of the observation group decreased during this period,plasma levels of β-endorphin increased,and plasma levels of substance P decreased.In the control group,VAS scores decreased significantly during this period,plasma levels of β-endorphin increased,and plasma levels of substance P decreased.2 weeks after treatment: VAS score of the observation group significantly reduced and it is lower than that of the control group during this period,the plasma level of β-endorphin further increased compared with that before treatment,and the plasma level of substance P significantly reduced compared with that before treatment.In the control group,VAS scores did not decrease significantly during this period,and the plasma levels of β-endorphin were still higher than before treatment,but the increase was slower,and the plasma substance P further reduced compare to the results before treatment.8 weeks after treatment: VAS score of the observation group further decreased and it is significantly lower than that of the control group during this period,plasma β-endorphin content increased again compare to the results before treatment,and it is significantly higher than that of the control group,and plasma substance P content was further reduced than that before treatment and significantly lower than that of the control group.In the control group,VAS score slightly increased during this period,plasma β-endorphin content was not significantly increased,and substance P was slightly higher than the results at 2 weeks.After the treatment period,the effective rates of the two groups were 89.29%(the observation group)and 63.33%(the control group)respectively.The effective rates of the observation group were significantly higher than that of the control group.Conculutions Microdose multi-site subcutaneous injection of botulinum toxin type A(BTX-A)for the treatment of postherpetic neuralgia(PHN)patients can effectively relieve the pain,and the long-term effect is particularly prominent,lasting effect.Plasma β-endorphins and substance P may be involved in the mechanism of PHN pain relief.