The study, published in Frontiers in Neuroscience, focused on the hypothalamic paraventricular nucleus, or PVN, a tiny cluster of neurons that acts as the brain’s master control center for the autonomic nervous system. The PVN regulates sympathetic outflow, the branch of the nervous system that raises heart rate and constricts blood vessels. In chronic hypertension, the PVN becomes dysfunctional: it pumps out excessive sympathetic drive, harbors local neuroinflammation, and runs a dysregulated renin–angiotensin system, the hormonal cascade that constricts vessels and promotes cardiac growth. This brain–heart crosstalk is what the researchers set out to modulate with needles.

The experiment used twenty-seven spontaneously hypertensive rats, a well-established genetic model of human essential hypertension, alongside nine normotensive Wistar-Kyoto controls. The hypertensive animals were randomly divided into three groups of nine: an untreated model group, an acupuncture group, and a losartan group receiving the standard antihypertensive drug at 20 milligrams per kilogram per day. The acupuncture protocol targeted three classical points, Taichong (LR3) on the foot, Baihui (GV20) on the crown of the head, and Sanyinjiao (SP6) on the lower leg, with sterile stainless-steel needles inserted 1 to 2 millimeters and manipulated by twirling for one minute per point. Treatments were delivered five mornings a week for twelve consecutive weeks, with model and control animals undergoing identical restraint handling to control for stress.

Blood pressure tracked by tail-cuff measurement told a clear story. Losartan lowered systolic and diastolic pressure significantly from week two onward, while acupuncture’s effect emerged at week four and then accumulated steadily. By week six, both interventions had produced marked, sustained reductions, and by week twelve losartan retained a modest edge in magnitude. Crucially, plasma norepinephrine, the chemical signature of sympathetic overactivation, fell significantly in both treated groups, indicating that the needles were not merely dilating vessels locally but damping the sympathetic fire originating in the brain.

The molecular heart of the study lies in the SIRT1/NF-κB/MAPK axis. SIRT1 is an NAD+-dependent deacetylase, a cellular housekeeping enzyme that deacetylates the NF-κB p65 subunit, thereby silencing the transcription factor that drives pro-inflammatory cytokine production. SIRT1 also restrains the mitogen-activated protein kinase pathways, including JNK, p38, and ERK1/2, which propagate stress and inflammatory signals. In the hypertensive rats, Western blotting of microdissected PVN tissue revealed depressed SIRT1 protein alongside elevated NF-κB p65 and phosphorylated MAPK species. Both acupuncture and losartan restored SIRT1 and suppressed the inflammatory signaling cascade, with losartan producing somewhat larger changes in this particular axis. Immunohistochemistry confirmed the pattern visually, showing more SIRT1-positive and fewer NF-κB p65-positive cells after treatment.

Downstream of this axis, the researchers measured the brain’s own renin–angiotensin system. Quantitative PCR showed that mRNA for angiotensin-converting enzyme (ACE) and the angiotensin II type 1 receptor (AT1R) were significantly upregulated in the PVN of untreated hypertensive rats, and both interventions brought these levels down to a comparable degree. This is notable because losartan is itself an AT1R blocker, yet acupuncture achieved similar suppression of the central RAS machinery, suggesting the needles engage the same hormonal circuitry through a neural route rather than a pharmacological one.

Neurotransmitter balance in the PVN also shifted. The hypertensive animals showed depleted GABA, the brain’s principal inhibitory transmitter, and elevated glutamate, its chief excitatory counterpart, a combination that biases the PVN toward heightened sympathetic output. Both treatments raised GABA and lowered glutamate, with no significant difference between the needle and drug groups. Pro-inflammatory markers told a similar story: serum IL-6 and IL-1β fell, and PVN mRNA for TNF-α, IL-1β, IL-6, and MCP-1 dropped markedly after either intervention.

The cardiac payoff was documented with echocardiography and histology. Untreated hypertensive rats displayed thickened left ventricular posterior walls and interventricular septa, reduced internal chamber diameter, and depressed ejection fraction, all hallmarks of maladaptive remodeling. Heart weight index and left ventricular mass index were elevated, and the hypertrophy markers ANP and BNP were upregulated in cardiac tissue. After twelve weeks, both acupuncture and losartan reduced wall thickness, improved chamber dimensions and ejection fraction, lowered the hypertrophy markers, and, on Masson-stained sections, shrank the blue collagen deposits that signal interstitial fibrosis. Losartan produced a slightly greater reduction in left ventricular mass index, but the two treatments were otherwise largely comparable in preserving cardiac structure and function.

The authors are careful about what the data do and do not prove. Because the study did not include PVN-targeted SIRT1 knockdown or overexpression, the causal role of SIRT1 remains associative rather than established. Blood pressure was measured by tail-cuff rather than radiotelemetry, so beat-to-beat dynamics could not be captured, and the absence of a non-acupoint sham control leaves open whether the effects are specific to the chosen points or reflect nonspecific needling and handling. Hypertension also involves interconnected brain regions beyond the PVN, and the contribution of these networks awaits exploration.

Even with those caveats, the findings carry weight. They suggest that a non-pharmacological intervention can engage the same central autonomic and inflammatory circuitry targeted by a first-line antihypertensive drug, restoring a deacetylase-driven brake on neuroinflammation within the brain’s sympathetic command center. If the mechanism translates to humans, acupuncture could serve as a complementary strategy for protecting the hypertensive heart, not by replacing medication but by working through the brain to quiet the signals that drive the muscle beneath it to overgrow.

Subject of Research: Central neural mechanisms of acupuncture-mediated cardioprotection in hypertension via the PVN SIRT1/NF-κB/MAPK signaling axis

Article Title: Acupuncture attenuates hypertension-induced myocardial hypertrophy: role of the SIRT1/NF-κ B/MAPK signaling axis in the hypothalamic paraventricular nucleus

Article References: Zhang, J., Wu, J., Wang, P., Wang, B., Li, S., Luo, G., Xiao, Z., & Liu, Q. (2026). Acupuncture attenuates hypertension-induced myocardial hypertrophy: role of the SIRT1/NF-κ B/MAPK signaling axis in the hypothalamic paraventricular nucleus. Frontiers in Neuroscience, 20, Article 1982426. https://doi.org/10.3389/fnins.2026.1982426

Image Credits: AI Generated

DOI: 10.3389/fnins.2026.1982426

Keywords: acupuncture, hypertension, myocardial hypertrophy, paraventricular nucleus, SIRT1, NF-κB, MAPK, neuroinflammation, renin-angiotensin system, sympathetic nervous system, attenuates, hypertension-induced