[Effect of lentiviral vector encoding on triggering receptor expressed on myeloid cells 1 on expression of inflammatory cytokine in septic mice infected by Bacteroides fragilis].
OBJECTIVE
To investigate the effect of triggering receptor expressed on myeloid cells 1 (TREM-1) vshRNA vector on expression of inflammatory cytokines and survival rate in septic mice infected by Bacteroides fragilis.


METHODS
(1) TREM-1 vshRNA vector was constructed. Bacteroides fragilis (2.5 x 10(9) CFU/mL, 0.5 mL) was intraperitoneally injected in each mouse, and septic model was reproduced after 12 hours. (2) One hundred and fifteen mice were divided into healthy control group (n = 3, HC), sepsis group (n = 28, S), TREM-1 vshRNA group (n = 28, T), TREM-1 vshRNA hd group (n = 28, Th), GFP group (n = 28, G) according to random number table. Mice in S, T, Th, G groups were firstly injected with isotonic saline, TREM-1 vshRNA 2 x 10(8) TU, TREM-1 vshRNA 1 x 10(8) TU, GFP siRNA through tail vein, and then sepsis was induced after 1 hour. Mice in HC group were injected with equal volume of isotonic saline through tail vein. Three mice in each group were sacrificed after 12 hours for determination of plasma level of TNF-alpha, IL-1 beta and IL-6, and level of TREM-1mRNA and its protein in hepatic tissue. The survival rate of other mice in each group was monitored for 72 hours. (3) In 125 mice sepsis was reproduced, among them 100 mice were injected with TREM-1 vshRNA 2 x 10(8) TU after 1, 2, 4, 6 hours through tail vein (25 mice at each time point), other 25 mice were injected with equal volume of isotonic saline as control. The survival rate of mice in each group was recorded 72 hours after injection.


RESULTS
(1) Compared with those in S group, the plasma level of TNF-alpha, IL-1 beta and IL-6 lowered in T and Th groups (P < 0.05), especially in T group, while those in G group showed no obvious difference (P > 0.05). (2) Compared with those in G group, the level of TREM-1mRNA and its protein in hepatic tissue in T and Th groups decreased (P < 0.01), especially in T group. (3) The survival rate of mice in S and G group was 16%, which was obviously lower than that in T and Th groups (76%, 44%, respectively, P < 0.05 or P < 0.01). (4) The survival rate of mice at 1, 2, 4, 6 hours after injection was 72%, 56%, 40%, 16%, respectively, while all that except at 6 hour after injection were higher significantly than that of control (P < 0.05 or P < 0.01).


CONCLUSIONS
The intervention with TREM-1 vshRNA can effectively decrease hepatic level of TREM-1 in septic mice induced by Bacteroides fragilis, inhibit inflammatory response, and improve the survival rate.
Song
Da-jiang
DJ
Department of Burns and Plastic Surgery, Xiangya Hospital, Central South University, Changsha 410008, China.
Huang
Xiao-yuan
XY
Ren
Li-cheng
LC
Yang
Xing-hua
XH
Xiao
Mu-zhang
MZ
Wang
Shuang
S
D000818:Animals; D001441:Bacteroides fragilis; D004195:Disease Models, Animal; D005822:Genetic Vectors; D016086:Lentivirus; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D012333:RNA, Messenger / Q000378:metabolism; D011971:Receptors, Immunologic / Q000235:genetics*; D018805:Sepsis / Q000378:metabolism* / Q000382:microbiology / Q000628:therapy*; D022701:Virosomes
D012333:RNA, Messenger; D011971:Receptors, Immunologic; C471763:Treml1 protein, mouse; D022701:Virosomes