Background Pulmonary heart disease (PHD) is a critical cardiopulmonary disease in high-altitude areas, with pulmonary hypertension (PH) as its central pathological basis. Cold and hypoxia are vital environmental characteristics of high-altitude regions; however, their joint effect on the hospitalization risk for PHD and the underlying biological mechanisms remain unclear. Objective To evaluate the associations of cold, hypoxia, and their joint exposure with PHD hospitalization risk, and to investigate PH-related pathological changes induced by combined cold and hypoxic exposure and the intervention effects of γ-aminobutyric acid (GABA) in rats. Methods Based on hospitalization data for 92986 PHD cases from 333 hospitals in Gansu Province (2018–2022), a generalized additive model (GAM) with a quasi-Poisson distribution was used to assess the associations between daily mean temperature, atmospheric oxygen content (AOC) and the daily number of PHD hospitalizations. Four joint exposure categories were constructed using the fifth percentile of temperature (P₅, −7.90℃) and AOC grades (high or low) to assess the associations between different exposure combinations and daily PHD hospital admissions. To further investigate PH-related pathological changes and the intervention effects of GABA, 24 specific-pathogen-free male Sprague–Dawley rats were randomly assigned to four groups (n=6): normal temperature and normoxia control group (NC), combined cold and hypoxia exposure group (CH), combined exposure plus low-dose GABA intervention group (CHL), and combined exposure plus high-dose GABA intervention group (CHH). After 5 weeks, pulmonary hemodynamics and vascular remodeling were evaluated. Gut microbiota and inflammatory cytokines in lung tissue were assessed using 16S rRNA sequencing and enzyme-linked immunosorbent assay (ELISA), respectively. Results Each 1 g·m⁻³ decrease in AOC and each 1 ℃ decrease in daily mean temperature were associated with 2.6% (RR=1.026, 95%CI: 1.024, 1.027) and 1.8% (RR=1.018, 95%CI: 1.015, 1.020) increases in PHD hospitalization risk, respectively. Compared with the non-low-temperature and high-AOC group, the low-temperature and low-AOC group had the highest risk estimate (RR=1.673, 95%CI: 1.567, 1.785). Animal experiments demonstrated that, compared with the NC group, rats in the CH group showed shortened pulmonary artery acceleration time (PAT) and increased mean pulmonary artery pressure (MPAP), right ventricular hypertrophy index (RVHI), pulmonary arterial wall thickness, and α-smooth muscle actin (α-SMA) expression (P<0.05). The Observed Species and Chao1 indices of the gut microbiota were significantly lower in the CH group than in the NC group (P<0.05), while levels of tumor necrosis factor-alpha (TNF-α) and interleukin-1beta (IL-1β) in lung tissue were elevated (P<0.05). GABA intervention improved selected hemodynamic, vascular remodeling, and inflammatory indices. Conclusion Decreases in daily mean temperature and AOC are associated with an increased risk of PHD hospitalization, with the highest risk estimate observed in the low-temperature and low-AOC group. Animal experiments suggest that combined cold and hypoxic exposure induce PH-related pathological changes accompanied by alterations in the gut microbiota and pulmonary inflammation. GABA may partially ameliorate these changes.

Aim To investigate the effect of curcumin on radiosensitivity of radioresistant nasopharyngeal carcinoma cell line CNE-2R and its mechanism.Methods The concentration of curcumin was screened by MTT assay.Dose-survival curves were obtained according to the colony forming test for L-Q matching and multitarget-single hitting matching,while SF2 and the correlation parameters of radiation biology were calculated.The changes of cell cycle in CNE-2R cells caused by curcumin were also tested by flow cytometry(FCM).The differential expression of genes related to cell cycle and DNA damage repair were detected by RT-qPCR.Results CNE-2R cells could not be inhibited by 10 μmol·L-1 curcumin.Dealt with 10 μmol·L-1 curcumin for 24 h,the value of α/β increased to 1 596 from 6.56;the value of SF2 decreased to 0.361 Gy from 1.93 Gy;the value of N decreased to 1.06 from 1.60;the value of D0 decreased to 2.12 from 3.27;the value of Dq decreased to 0.12 from 1.53.FCM showed that the cells in G2 phase had a significant increase and the cells in S phase had a significant decrease after dealt with 10 μmol·L-1 curcumin for 24 h.The expression of CDK4 was significantly up-regulated and GADD45g,BRCA1 were significantly down-regulated.Conclusion Curcumin radiosensitizes nasopharyngeal carcinoma cell line CNE-2R by changing cell cycle and affecting DNA damage repair through regulating the expression of CDK4,GADD45 g and BRCA1.