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.