PROTECTIVE EFFECTS OF CARICA PAPAYA LEAF EXTRACT ON THE GUT–LUNG AXIS IN ASBESTOS-EXPOSED RATS - Usman Haider; Bilal Aslam; Najeeb ullah khan; Wania Nasir; Muhammad Saad Tariq (Journal of Animal and Plant Sciences, 2026)
The gut-lung axis is a key regulator of host immunity illustrating the influence of gut microbiota on respiratory system through systemic and mucosal immune pathways. The purpose of this study was to evaluate the effect of asbestos-induced inflammation on the gut–lung axis by examining changes in gut microbiota composition, and to determine the impact of C. papaya extract in mitigating of induced inflammation and microbial dysbiosis. The study followed a completely randomized design-based experimental trial, employing a total of 32 male Albino Wistar rats weighing approximately 150-160g on average and aged 8 weeks. The experimental units were assorted randomly into four groups, namely Negative Control Group (receiving no induction or treatment), Positive Control Group (exposed to asbestos fibers through inhalation and oral ingestion), Standard treatment group (asbestos exposure + Naproxen 10 mg/kg b.wt orally) and Herbal Treatment Group (asbestos exposure + C. papaya extract 500 mg/kg body weight) orally daily. All experimental rats were maintained raised a period of two weeks (14 days). Fecal samples were collected to assess fecal consistency, gut microbiota composition by qRT-PCR, and short-chain fatty acid (SCFA) levels using FTIR. Bronchoalveolar lavage fluid (BALF) was obtained for cell count and mucus grading. Statistical assessment of numerical data employed repeated measure Analysis of Variance (ANOVA) followed by Tukey’s Post hoc test with p≤0.05 considered a significant difference among all experimental groups. The FTIR results demonstrated improved absorption bands of SCFAs in Herbal Treatment group compared to other groups, with enhance hydrocarbon stretch patterns. The BALF smear showed high lymphocytic infiltrate in Positive Control Group compared to treatment groups, indicative of acute asbestos toxicity, and a marked decrease (p≤0.05) in lymphocyte infiltrate in Herbal Treatment group, showing the effectiveness of C. papaya in immunomodulation. The qPCR results for microbial analyses showed a significant increase (p≤0.05) in pathogenic bacterial strains and a subsequent decrease (p≤0.05) in commensal microbiota in the Positive Control group compared to treatment groups, and this dysbiotic profile was restored to high commensal: low-to-pathogenic ratio in Herbal treatment group. The qRT-PCR results for genetic studies showed a significant upregulatory pattern (p≤0.05) in Herbal treatment group after asbestos exposure, compared to a significant down-regulation (p≤0.05) in Positive Control group, which was concomitant to the Histopathological observation where distorted mucosal layers in Positive Control group were parallelly were restored in Herbal treatment group with significant improvement in mucosal inflammatory changes and overall histoarchitecture. The obtained results suggest the therapeutic role of C. papaya extract in mitigating inflammation and partial restoration of dysbiosis associated with asbestos exposure.
Keywords: journal article; Microbiome; Oxidative Stress; Environmental Toxins; Dysbiosis; BALF