<i>Premna microphylla</i> Turcz. as a novel radiation protector: Alleviating radiation-induced colonic injury in mice

Abstract Objectives Radiation enteropathy is a common complication of cervical cancer radiotherapy, and there is currently no effective treatment. This study evaluates the radioprotective effect of Premna microphylla Turcz. (PMT) on radiation-induced colon injury in mice. Materials and Methods An 8 Gy abdominal irradiation model was established in mice, which were then gavaged with low (0.325 g/kg), medium (0.65 g/kg), or high (1.3 g/kg) doses of PMT. Weight and other routine information were recorded. The mice were euthanized on the 7th day after radiotherapy. Colonic tissue was collected for observing structural changes. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) was used to detect inflammation infiltration in colon tissue. 16S rRNA gene sequencing was performed to analyze the alterations in gut microbiota composition. Hepatic and renal function assessments were conducted to evaluate the safety profile of PMT. Results PMT at medium dose significantly reduced radiation-induced weight loss (P&amp;lt;0.05). PMT alleviated gastrointestinal discomfort and partially reduced radiotherapy-induced faecal occult blood, although these effects were not statistically significant. Both medium and high doses of PMT reversed the shortening of colon length caused by radiotherapy (both P&amp;lt;0.05). The medium- and high-dose PMT improved the colonic inflammatory microenvironment by reducing the expression of inflammatory factors and chemokines (IL-1β, IL-6, IFN-γ, TNF-α, and Cxcl1) (P&amp;lt;0.05). PMT restored the diversity of the gut microbiota and normalized the Bacteroidetes/Firmicutes ratio disrupted by radiation. Beyond intestinal protection, PMT administration at all doses significantly reduced the postirradiation levels of serum creatinine (Cr), alanine aminotransferase (ALT), and aspartate aminotransferase (AST) (all P&amp;lt;0.05). Conclusions PMT, particularly at medium doses, has potential for treating radiation-induced colonic injury in mice without causing hepatorenal toxicity, providing a novel therapeutic approach for radiation-induced colonic diseases.