Immunoregulatory Effect of Jiedu Tongluo Shengjin Prescription on Sjögren's Syndrome Mice Based on Stability of Treg Cells / 中国实验方剂学杂志

ABSTRACT

ObjectiveTo investigate the effect of different doses of Jiedu Tongluo Shengjin prescription （JTSP） on serum interleukin-6 （IL-6）， tumor necrosis factor-α （TNF-α） and forkhead box P3 （FoxP3） in submandibular gland of NOD/Ltj mice with Sjögren's syndrome， and to explore the mechanism of JTSP on immune regulation in NOD/Ltj mice. MethodThirty NOD/Ltj mice （eight weeks old） were randomly divided into model group， JTSP low-dose group， JTSP medium-dose group， JTSP high-dose group and hydroxychloroquine group， and were administrated with normal saline， JTSP 9， 18， and 36 g·kg-1， and hydroxychloroquine 60 mg·kg-1 daily， respectively from the age of 12 weeks. Six ICR mice were given an equal amount of normal saline by gavage as the control group. During the experiment， daily water consumption and saliva secretion of mice at the age of 9， 12， 16 weeks were recorded. After 4 weeks of administration， submandibular gland and spleen tissues were dissected to calculate corresponding indexes. The pathological morphology of submandibular gland was observed by hematoxylin-eosin （HE） staining. Meso Scale Discovery （MSD） and immunohistochemistry were employed to detect the serum levels of IL-6， TNF-α and IL-10， and the expression and distribution of FoxP3 in submandibular gland， respectively. The protein expression of FoxP3 in mouse submandibular gland was determined by Western blot， and the mRNA expressions of FoxP3 and TNF-α were determined by real-time polymerase chain reaction （Real-time PCR）. ResultCompared with the control group， the model group presented increased daily water consumption， decreased saliva secretion， lowered submandibular gland index， elevated pathological score of submandibular gland， up-regulated serum IL-6 and TNF-α and mRNA expression of TNF-α while down-regulated serum IL-10 and protein and mRNA expressions of FoxP3 in submandibular gland （P<0.05）. Compared with the conditions in model group， daily water consumption in JTSP groups was reduced while saliva secretion was increased， especially in medium-dose and high-dose groups （P<0.05）， and there was an increase in the submandibular gland index of JTSP medium-dose group （P<0.05） while a decrease in the spleen index of JTSP high-dose group （P<0.05）. Additionally， JTSP groups had lower pathological score of submandibular gland than the model group （P<0.05）， especially high-dose group， as well as lower serum IL-6 and TNF-α and mRNA expression of TNF-α while higher serum IL-10 （P<0.05）. JTSP at medium and high doses up-regulated the protein and mRNA expressions of FoxP3 in submandibular gland （P<0.05）. ConclusionJTSP may inhibit the secretion of inflammatory cytokines by regulating the stability of FoxP3+ regulatory T （Treg） cells， thus alleviating the systemic immune inflammation in Sjögren's syndrome.