[Studies on the expression of mRNA of anti- and pro-inflammatory cytokines in acute lung injury induced by lipopolysaccharide in rat].

OBJECTIVE: To study the role of pro-inflammatory cytokines including tumor necrosis factor-alpha(TNF-alpha), interleukin-1beta(IL-1beta), IL-6, and anti-inflammatory cytokines including IL-4, IL-10, and IL-13 in acute lung injury(ALI). METHODS: Reverse transcription-polymerase chain reaction(RT-PCR) were used to assess the expressions of mRNA of TNF-alpha, IL-1beta, IL-6, IL-4, IL-10 and IL-13 in the lung tissue after lipopolysaccharide challenge. RESULTS: The expression of TNF-alpha mRNA was seen to peak at 1 hour and IL-6 mRNA at 4 hours in lung tissue after the challenge. The highest expression of mRNA of other cytokines, such as IL-1beta, IL-4, IL-10 and IL-13 in lung tissue appeared 2 hours after LPS-induced lung injury. CONCLUSION: TNF-alpha is an early presenting cytokine in ALI, and IL-6 may play an important role in delayed development of ALI. The over-expression of anti-inflammatory cytokines IL-4, IL-10 and IL-13 may act as promoters rather than protectors in amplification of inflammatory process.

[Down-regulation of Toll-like receptor 4 is related to the tolerance to lipopolysaccharide in rat alveolar macrophages].

OBJECTIVE: To explore the change of expression of Toll-like receptor 4 (TLR(4)) related to the tolerance to lipopolysaccharide (LPS) in rat alveolar macrophages. METHODS: Alveolar macrophages obtained from 30 Wistar male rats were randomly divided into a control group, a LPS single-dose stimulation group and a LPS double-dose stimulation group. IL-10 and IL-18 mRNA in alveolar macrophages and the level of TNF-alpha, as indexes of LPS tolerance, were measured by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) and enzyme linked immunoads orbeen assay (ELISA), respectively. The expression of TLR(4) was detected by Western Blot. RESULTS: The level of TNF-alpha, and the mRNA for IL-10 and IL-18, and the protein of TLR(4) in the alveolar macrophages stimulated with single-dose LPS (100 ng/ml) were highly increased as compared with the control group [(0.760 +/- 0.030) micro g/L, 2.18 +/- 0.09, 1.83 +/- 0.07, 2.060 +/- 0.060, 148.3 +/- 1.4 vs (0.450 +/- 0.010) micro g/L, 1.16 +/- 0.04, 0.97 +/- 0.03, 1.320 +/- 0.020, 58.1 +/- 0.4 (P < 0.01)], while they were significantly decreased in the alveolar macrophages after re-stimulation with double-dose LPS (100 ng/ml and 500 ng/ml). CONCLUSIONS: (1) The tolerance to LPS in alveolar macrophages can be induced by re-stimulation with LPS. (2) The down-regulated expression of TLR(4) is related to tolerance to LPS.

[Changes of interleukin-6 and Janus kinases in rats with hypoxic pulmonary hypertension].

OBJECTIVE: To investigate the expressions of interleukin 6 (IL-6) and Janus kinases (JAKs) in rats with hypoxia induced pulmonary hypertension (HPH). METHODS: Sixty male Wistar rats were randomized into 5 groups with 12 animals in each: a one-week hypoxic group (H(1) group), a two-week hypoxic group (H(2) group), a three-week hypoxic group (H(3) group), a four-week hypoxic group (H(4) group), a normal oxygen group (N group). The rat model of HPH was replicated in normal baric hypoxic cabin. The levels of IL-6 and JAKs mRNA were measured by using reverse transcription-polymerase chain reaction (RT-PCR); The expression of JAKs protein and cell morphologic changes were observed by immunohistochemistry. RESULTS: (1) The levels of IL-6 mRNA in H(1) (1.67 +/- 0.09), H(2) (2.26 +/- 0.12) and H(3) (1.55 +/- 0.11) groups were significantly higher than that in N group (1.20 +/- 0.11, all P < 0.01). The levels of JAK1 mRNA in H(1) (2.11 +/- 0.09), H(2) (2.85 +/- 0.12) and H(3) (2.36 +/- 0.13) groups were significantly higher than that in N group (1.62 +/- 0.10, all P < 0.01); The levels of JAK2 mRNA in H(1) (1.41 +/- 0.07), H(2) (2.02 +/- 0.13) and H(3) (1.36 +/- 0.09) groups were significantly higher than that in N group (1.01 +/- 0.09, all P < 0.01); The levels of JAK3 mRNA in H(1) (0.86 +/- 0.11), H(2) (1.45 +/- 0.10) and H(3) (0.91 +/- 0.13) groups were significantly higher than that in N group (0.55 +/- 0.08, all P < 0.01). The levels of TYK2 mRNA in H(1) (1.36 +/- 0.10), H(2) (1.76 +/- 0.11) groups were significantly higher than that in N group (0.57 +/- 0.07, all P < 0.01). The levels of IL-6 and JAKs mRNA in H(2) group were significantly higher than those in H(1) and H(3) groups (all P < 0.01). (2) Histochemical staining of JAK1 and JAK3 in H(3) group showed yellow cytoplasm of alveolar wall cells, bronchial wall cells and small blood wall cells; The active protein contents of JAK1 (5.36 +/- 0.32) and JAK3 (4.88 +/- 0.29) were markedly increased as compared with N group (1.52 +/- 0.18, 1.22 +/- 0.09, respectively; all P < 0.01) by TIGER image analysis method. CONCLUSIONS: The levels of IL-6, JAKs mRNA and protein can increase in pulmonary tissues of rats with HPH. It suggests that IL-6/JAKs pathway may take part in the pathogenesis of HPH.