# Oral and Intranasal Administration of Polydeoxyribonucleotide Isolated from Porphyra sp. Ameliorates Acute Lung Injury via Suppressing Proinflammatory Cytokine Production in Mice

## TL;DR

A compound from seaweed reduces lung inflammation in mice by suppressing harmful immune signals when given orally or through the nose.

## Contribution

The study explores a novel marine-derived compound's efficacy in treating lung inflammation via two administration routes.

## Key findings

- Ps-PDRN reduced fever, edema, and lung tissue damage in mice with acute lung injury.
- Both oral and intranasal Ps-PDRN suppressed proinflammatory cytokines and chemokines in mice.
- In vitro tests showed Ps-PDRN inhibited cytokine production in macrophages dose-dependently.

## Abstract

Acute lung injury (ALI) is a severe inflammatory condition with high mortality rates, necessitating the development of effective therapeutic agents. Polydeoxyribonucleotide (PDRN), a DNA-derived compound known for its tissue repair and anti-inflammatory properties, has gained attention as a potential therapeutic agent. However, the efficacy of PDRN derived from marine sources, particularly Porphyra sp. (laver), remains unexplored in respiratory inflammation. In this study, we investigated the protective effects of Porphyra sp.-derived PDRN (Ps-PDRN) against LPS-induced ALI in mice through two administration routes: intranasal (IN) and oral (PO). Ps-PDRN treatment significantly attenuated fever, pulmonary edema, and histopathological changes in LPS-challenged mice. Both IN and PO administration of Ps-PDRN markedly reduced proinflammatory cytokines (TNF-α, IL-1β, and IL-6) and chemokines (MCP-1, RANTES, CXCL1, and MIP-2) in bronchoalveolar lavage fluid (BALF) and serum. Comparative analysis of the two administration routes revealed distinct efficacy profiles, with oral administration demonstrating superior chemokine inhibition, while intranasal delivery showed advantages in certain cytokine suppression. Histological examination revealed that Ps-PDRN preserved alveolar architecture and reduced inflammatory cell infiltration. Furthermore, in vitro studies using RAW 264.7 macrophages demonstrated that Ps-PDRN inhibited LPS-induced production of proinflammatory cytokines, such as TNF-α and IL-6, in a dose-dependent manner. These findings suggest that Ps-PDRN exerts potent anti-inflammatory effects against ALI through both local and systemic administration routes, highlighting its potential as a novel therapeutic agent for inflammatory lung diseases.