FSHW | 蚕蛹的酶解和采用不同免疫途径的动物模型进行致敏性评价

Introduction

蚕蛹是甲壳类昆虫的一种，在中国食用蚕蛹已有几千年的历史。蚕蛹因其营养价值而广受欢迎，在中国、日本、韩国和印度等亚洲国家被认为是一道美味佳肴。据报道，对蚕蛹过敏的人会出现各种临床症状，如瘙痒、头晕、头痛、恶心、呕吐、震颤、意识障碍、哮喘甚至严重休克。因此，人类对蚕蛹的消费受到了极大的限制。

酶解技术已广泛应用于食品加工，并成功地改变了食品蛋白质的营养、生物活性和功能特性。迄今为止对蚕蛹过敏的研究很少。本研究旨在探讨蚕蛹蛋白质过敏的可能机制以及酶解对蚕蛹致敏性的影响。本研究对开发低致敏或非致敏性蚕蛹产品具有重要意义。

Results and discussion

文中选用小鼠两种主要的致敏途径包括灌胃(i.g.)和腹腔注射(i.p.)。免疫小鼠过敏症状评分、直肠温度和组胺水平见图1。我们观察到两种不同免疫途径蚕蛹蛋白（SP）免疫小鼠的致敏性评分有明显差异。SP可诱导小鼠产生过敏反应，且小鼠更容易通过i.p.途径致敏。蚕蛹蛋白肽（SPP）组的致敏性显著降低，两种不同途径的SPP免疫小鼠均未出现明显的临床症状。

采用间接ELISA法检测IgE、IgG和IgG1，见图2。SP免疫小鼠IgE、IgG、IgG1水平均升高，其中IgG水平最高。结果也表明腹腔免疫方案比口服免疫方案更有效。两种途径免疫的SPP组IgG，IgG1均较SP组显著降低。i.p.免疫方案是有效的，更适合于建立SP小鼠致敏模型，且SPP组特异性抗体明显降低，提示酶解可降低SP的致敏性。

脾细胞分泌的IL-4、IL-5、IL-13和IFN-γ水平见图3。SP处理的小鼠中IL-4，IL-13水平明显升高；SPP组IL-4、IL-5、IL-13、IFN-γ水平与对照组比较无明显差异。

为探讨蚕蛹对空肠肠损伤的过敏性作用，采用两种不同途径免疫小鼠的组织及肠损伤评分见图4。i.p.免疫SP组的过敏反应可导致明显的肠道损伤。结果表明，i.p.免疫途径对Balb/c小鼠的过敏反应更为明显。两种不同途径SPP处理小鼠的空肠组织基本无病变，说明酶解可大大降低致敏性。

总之，SPP可作为一种低过敏性、功能性的食品和药品原料资源。作者比较了两种致敏途径对小鼠的致敏作用，发现腹腔注射引起的过敏反应更为明显。

Conclusion

本文首次通过动物模型的致敏和蚕蛹酶解产生多肽的过敏原性的变化来探讨蚕蛹过敏的潜在机制。研究结果显示，蚕蛹蛋白可显著引起过敏反应，酶解技术可以显著降低蚕蛹的抗原性。因此，酶解技术是降低蚕蛹致敏性的有效方法。

Enzymatic hydrolysis of silkworm pupa and its allergenicity evaluation by animal model with different immunization routes

Yan Dai^a,b, Meijia Huang^a,b, Yujuan Xu^c, Lixia Mu^c, Jingyan Gao^b, Hongbing Chen^a,d, Zhihua Wu^a,d, Anshu Yang^a,d, Yong Wu^a,d, Xin Li^a,b^,*

^a State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China

^b School of Food Science and Technology, Nanchang University, Nanchang 330047, China

^c Sericultural and Agri-Food Research Institute Guangdong Academy of Agricultural Sciences, Key Laboratory of Functional Foods, Ministry of Agriculture and Rural Affairs, Guangdong Key Laboratory of Agricultural Products Processing, Guangzhou 510610, China

^d Sino-German Joint Research Institute, Nanchang University, Nanchang 330047, China

*Corresponding authors.

Abstract

Silkworm pupa is a nourishing food with high nutritional value, but its consumption has been greatly limited given its allergenicity. Enzyme hydrolytic technique is recognized as an effective method to reduce the allergenicity of protein. In this study, we aimed to investigate the effect of enzymolysis on the allergenicity of silkworm pupa. Crude silkworm pupa protein was extracted through alkali extraction and acid precipitation, which included 5 proteins with the molecular weights ranging from 34 kDa to 76 kDa, and silkworm pupa were then hydrolyzed by alkaline protease. The allergenicity of silkworm pupa protein and its enzymatic hydrolysates was evaluated by establishing BALB/c mice model, and the mice were immunized via intragastric gavage and intraperitoneal injection, respectively. The results indicated that the intraperitoneal injection immunization route induced more by detecting with antibodies, histamine and Th2-related cytokines. Moreover, mice treated with silkworm pupa protein peptide displayed no obvious allergic symptoms, indicating that enzyme hydrolytic technique could significantly reduce the allergenicity of silkworm pupa.

Reference:

DAI Y, HUANG M J, XU Y J, et al. Enzymatic hydrolysis of silkworm pupa and its allergenicity evaluation by animal model with different immunization routes[J]. Food Science and Human Wellness, 2023, 12(3): 774-782. DOI:10.1016/j.fshw.2022.09.011.