IL‑4 alleviates CIRI by suppressing autophagy via the HIF‑1α/Bcl‑2/BNIP3 pathway in rats.

This paper was designed for delving into the mechanism adopted by interleukin‑4 (IL‑4) to relieve cerebral ischemia‑reperfusion injury (CIRI) in rats via suppressing autophagy. Herein, rats stochastically fell into sham operation (sham), model (RI), model + IL‑4 intervention (IL‑4), model + HIF‑1α inhibitor (2‑methoxyestradiol, 2ME2) and model + IL‑4 + 2ME2 (IL‑4 + 2ME2) groups. Next, western blotting was utilized to examine the protein expressions of microtubule‑associated protein 1 light chain 3 (LC3), p62, hypoxia‑inducible factor 1‑alpha (HIF‑1α) and Bcl‑2/adenovirus E1B 19 kDa‑interacting protein 3 (BNIP3). Relative to RI group, IL‑4 group had a significantly lower neurological impairment scale (NIS) score and an overtly lower apoptosis rate of neurons as well as a strikingly smaller cerebral infarction volume and number of autophagosomes (P<0.05). The LC3II/LC3I ratio and HIF‑1α and BNIP3 protein expressions dropped, but p62 protein expression rose pronouncedly in IL‑4 group (P<0.05). In contrast to those in RI group, the NIS score, neuronal apoptosis rate, cerebral infarction volume and autophagosome number were strikingly reduced (P<0.05). The NIS score, cerebral infarction volume, neuronal apoptosis rate, autophagosome number, LC3II/LC3I ratio and protein expressions of HIF‑1α and BNIP3 plummeted, while p62 protein expression sharply rose in IL‑4 + 2ME2 group relative to those in IL‑4 group (P<0.05). IL‑4 suppresses cell autophagy by inhibiting the HIF‑1α/BNIP3 pathway, thus relieving CIRI in rats.