(717) Effects of pregnancy and electroacupuncture on pancreatic beta cell mass in rats with diet-induced obesity

Friday, February 10, 2023

10:30 AM – 12:00 PM

Objective: We previously demonstrated that repeated electroacupuncture (EA) throughout pregnancy improves insulin sensitivity (reflected by higher glucose infusion rates during a hyperinsulinemic-euglyemic clamp; Figure 1A) in a high fat/sucrose (HFS) diet-induced rat model of maternal obesity. Compared to non-obese, non-pregnant controls (Con group), pancreatic weight (Figure 1B) was unaffected by diet (HFS group) but increased 24% in HFS-exposed pregnancy (HFS-P group); EA abolished this effect (HFS-P+EA group). Herein, we examined the impact of diet, pregnancy and EA on ß-cell mass (BCM). We hypothesized that BCM would reflect pregnancy/EA-induced changes in insulin resistance.

Study Design: Whole paraformaldehyde fixed paraffin-embedded pancreata from Con, HFS, HFS-P and HFS-P+EA groups (n=5 each) were sectioned and collected at 400µm intervals. Five representative sections were subjected to multiple-labelling immunofluorescence staining for insulin/glucagon and imaged on a Nikon Ti-E morphometry workstation. Using NIS Elements software, ß-cell fractional surface area was measured for each rat and BCM was calculated. Plasma insulin was measured using an ultrasensitive rat-specific ELISA. Groups were compared by one-way ANOVA followed by post-hoc LSD tests.

Results: Fractional ß-cell area and BCM were unaffected by HFS diet or EA (Con vs. HFS, and HFS-P vs. HFS-P+EA: p >0.05) but both were significantly increased by pregnancy (Figure 2). Plasma insulin levels at study termination were positively correlated with BCM (r=0.650, p=0.003) and were significantly higher in HFS-P/HFS-P+EA (34.3±4.2/30.3±.3.7 µIU/ml) vs. Con/HFS (7.3±1.7/5.0±1.8 µIU/ml) groups (p < 0.01).

Conclusion:

Pregnancies established after ≥6 weeks exposure to HFS diet were characterized by maternal hyperinsulinemia and BCM expansion, neither of which were measurably impacted by EA. Previously demonstrated EA-induced increases in insulin sensitivity were not associated with changes in BCM in the short term. Previously observed changes in pancreatic weight following EA likely reflect differences in exocrine and/or stromal elements of the pancreas.

Primary & Presenting Author(s)

Elizabeth Kelley, BS (she/her/hers)
Medical Student
University of Vermont
Burlington, Vermont, United States

Coauthor(s)

MS
Morgan Sekhon, BS, MD
Resident
University of Vermont
Burlington, Vermont, United States
MK
Megan Kawasaki, BA, MD
University of Vermont
Burlington, Vermont, United States
KM
Keara McElroy-Yaggy, BS
Research Technician
University of Vermont
Colchester, Vermont, United States
DC
David Coggin-Carr, FRCOG, MBBS, MD, MSc, PhD
Clinical Assistant Professor
University of Vermont
Burlington, Vermont, United States
TJ
Tom Jetton, BS, MS, PhD
Professor
University of Vermont
Colchester, Vermont, United States