Effects of Lesion of the Median Preoptic Nucleus (MnPO) on the Gut Microbiome

Hypertension is a leading cause of premature death, and an estimated 1.28 billion people are affected by the condition, but only 21% of that population have it managed. Gut dysbiosis has been associated with hypertension, but the cause and effect of these changes in the gut microbiome is still unclear. Circumventricular organs (CVO) within the brain have been identified to play an integral role in hypertension. One such CVO, the organum vasculosum of the lamina terminalis (OVLT), as well as its downstream nucleus, the median preoptic nucleus (MnPO) have been previously shown to be important in the development of certain forms of hypertension. Our lab demonstrated that a lesion of the OVLT (OVLTx) or MnPO (MnPOx) in rats attenuates certain forms of hypertension. Lesion of the OVLT or MnPO attenuated hypertension with an altered GI microbiome, but the sole effect of OVLTx or MnPOx on the gut microbiome is unknown. Gut microbiomic data from OVLTx rats were statistically different from sham rats in most gut regions, with a less diverse population overall and a higher relative abundance of Ligilactobacillus spp. The purpose of the present study was to further examine changes in the gut microbiome in MnPOx rats. Male Sprague Dawley rats underwent electrolytic lesion of the MnPO or sham operations using stereotaxic surgery. Tissues were harvested 7 days post op for lesion verification and microbiome analysis. MnPOx rats (n=5) had a lower abundance of Ligilactobacillus spp, as well as distinct clustering demonstrated by PCoA analysis and decreased Shannon diversity in most tissues compared to sham rats (n=4). In conclusion, the MnPO lesion itself has effects on the diversity of the gut microbiome, albeit separate and distinct from an OVLT lesion, which may suggest a divergent OVLT – MnPO – gut microbiome link that may contribute to attenuating hypertension. University of Minnesota Grant-In-Aid. University of Minnesota Lillehei Heart Institute Collaborative Pilot Grant This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.