CCL2 and pulmonary edema: Furthermore, a separate study conducted on rats experiencing high-altitude pulmonary edema (HAPE) as a result of acute hypobaric hypoxia (9142 m for 5 h) also demonstrated elevated levels of proinflammatory molecules, including TNF-α, monocyte chemoattractant protein-1 (MCP-1), INF-γ, IL-6, and TNF-β, within the bronchoalveolar lavage.