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Anti-allergic effects of probiotic Lactobacillus rhamnosus GG (LGG) on allergic rhinitis induced by ovalbumin in rats

To explore the potential pharmaceutical effects of Lactobacillus rhamnosus GG (LGG) in treating allergic rhinitis in a rat model sensitized by ovalbumin (OVA). 8 week-old male Wistar rats sensitized with OVA were adopted as study objects. Allergic rhinitis animal model was prepared by OVA sensitization from day 1 to day 63. ELISA was performed to evaluate the serum level of histamine, total IgE and OVA-specific IgE in OVA sensitized rats. Flow cytometry (FCM) was performed to detect the CD4+CD25+ T-cells proportion alteration in groups treated with or without LGG. Passive cutaneous anaphylaxis (PCA) was performed to evaluate the inhibitory effect of LGG on allergic responses. qPCR was used to verify the secretion of CCL5, CCL24, CCL26 and expression of CCR3 and IL-3. WB was also used to confirm the stimulation of IL-3 and suppression of CCR3. Our results showed that LGG is protective in OVA-induced allergic rhinitis rat model. The serum level of histamine, total IgE and OVA specific IgE were significantly elevated in OVA sensitized allergic rhinitis rats assayed by ELISA indicating the effectiveness of our animal model. Further ELISA results showed that decrease of these cytokines treated with LGG. FCM results showed that the proportion of CD4+CD25+ and Foxp3+Treg cells in the mesenteric lymph nodes (MLNs) of OVA-sensitized allergic rhinitis rats was increased with LGG treatment. PCA results in vivo indicated the obvious anti-allergic effects of LGG treatment with a significant decrease of the amount of dye. Secretion and expression of CCL5, CCL24 and CCL26 were down regulated by LGG treatment; the expression of their receptor CCR3 was also decreased. IL-3 induction was detected by qPCR and WB after treatment of LGG. LGG treatment can significantly decrease the allergic responses of OVA-induced rhinitis rat models. LGG treatment was associated with a total decrease of allergic responses, secretion of CCL5, CCL24 and CCL26. LGG could also down regulate expression of CCR3 through IL-3 induction.

Author(s): Liu Wei, Liu Fei, Xiao Ning, Tang Haiming, Guo Lixin, Meng Xianqin