预防性双类似物鼻粘膜耐受对EAMG的影响

Prophylactic effects of nasal tolerance with dual analogue on experimental autoimmune myasthenia gravis in Lewis rats

目的选择双类似物(Lys262-Ala207)通过不同时间点对实验性自身免疫性重症肌无力(EAMG)模型进行鼻粘膜耐受预防性给药,观察其临床及免疫指标变化,并评价疗效,探讨预防性鼻粘膜耐受在EAMG中的预防作用机制。方法应用乙酰胆碱受体(AChR)加CFA致敏Lewis大鼠建立EAMG模型,并在致敏前10 d(预防耐受A组)及致敏当日(预防耐受B组)给予耐受肽Lvs262-Ala207及相应对照组CA、CB采用相同剂量对照肽MBP-p83-99鼻腔给药。检测给药后A、B组及相应对照组大鼠的体重、临床评分、肌电图、肌肉中AChR含量丢失变化及致敏第42 d血清抗AChR抗体IgG含量。结果急性期和慢性期A、B组体重明显超过相应对照组,临床症状明显轻于相应对照组,慢性期A组体重明显超过B组、病情明显轻于B组;A、B组低频重复电刺激出现衰减反应D5阳性率低于相应对照组;A、B组肌肉AChR含量丢失分别明显低于相应对照组,而A组低于B组;慢性期42 d A、B组IgG含量明显低于相应对照组,同时A组明显低于B组。结论本实验表明,预防耐受的疗效与自身免疫启动时间有关,启动前优于启动时耐受;双类似物鼻粘膜耐受预防不仅可有效地抑制临床症状,且可特异性减低致病性循环抗体含量和减少神经肌接头AChR含量丢失,为采用双类似物鼻粘膜耐受防治人类重症肌无力(MG)提供了依据。

Objective To study the prophylactic effects of nasal tolerance with a dual analogue (Lys262-Ala207) on the model of experimental autoimmune myasthenia grfavis (EAMG) and the underlying mechanisms, and to observe the clinical and immunological changes and evaluate the effect. Methods To compare the effects of the predetermined dosage of the Lys262-Ala207 at different time points, dual analogues or control peptides MBP-p83-99 were given nasally before 10 days (group A and control A) or on the day (group B and control B) of immunization with acetylcholine receptor (AChR) in complete Freund's adjuvant for 10 consecutive days. The body weight and clinical scores were evaluated for 50 days post immunization. CAMP was measured. The loss of AChR within the neuromuscular junction (NMJ) and the levels of anti-AChR IgG in serum were tested by RIA. Results Compared with the corresponding control groups, Lewis rats in group A or B were developed EAMG with increased weight and reduced severity in acute and chronic phases, decremental D5 positive rate of CAMP. The loss of AChR was reduced within NMJ and the levels of anti-AChR IgG were decreased in group A and B compared to the corresponding control groups. Above results in A were better than B. Conclusion Nasal administration with a dual analogue at two different time points before and on the day of immunization, the subsiding disease was associated with decreasing the loss of muscle AChR content within NMJ and the amount of anti -AChR IgG in serum in group A and B receiving the Lys262-Ala207 compared to rats receiving control peptides. The prophylactic effects of dual analogue in Group A before the immunization were better than Group B on the immunization. Thus, our results might give light to mucosal tolerance with dual analogue as an alternative maneuver of prevention and treatment in human MG.