Neuroendocrine Effects of Inhaling Emissions Generated by 3-Dimensional (3D) Printing with Polycarbonate Stock

Details

• Personal Author:
  Krajnak, Kristine M. ; Mandler, W. Kyle ; Waugh, Stacey ; Knepp, Alycia K. ; McKinney, Walter G. ; Battelli, Lori A. ; Chapman, P. D. ; Qian, Yong
• Description:
  Background and Purpose: Inhalation of emissions (particulate and volatile chemicals) generated while 3D printing with polycarbonate feedstock results in the deposition of bisphenol A (BPA) in the respiratory system and affects reproductive function and circulating concentrations of anterior pituitary hormones and gonadal steroids in rats exposed to 3D-printer emissions (3DE). The goal of this study was to look at possible mechanisms that might underlie these changes. We hypothesized that inhalation of 3DE affects reproductive and metabolic hormone release by affecting olfactory bulb signaling, or by interfering with hypothalamic and pituitary regulation of hormone release. Methods: Male Sprague Dawley rats (n = 36) were exposed to filtered air or emissions generated using PC filament with five 3D-printers (exposure 4 h/d). The 4 h average particle concentration in the breathing space was 2.15 mg m3. Animals were exposed 1d or 4 d/week until they had been exposed for 8 or 30d. Using BPA measured during a single exposure, a deposition model estimated BPA deposition in the respiratory system was 0.115 µg/day. Circulating hormones were measured using ELISAs and qRT-PCR was performed in pituitary, hypothalamic and olfactory bulb tissue collected 1d after 1, 8 or 30d exposure to measure changes in the expression of inflammatory factors, neuroendocrine factors, factors involved in regulating oxidative stress, and transcription factors. Data were analyzed using 2(condition) x 3 (exposure time) ANOVAs. Statistically significant interactions were analyzed using either a one-way ANOVA to assess changes over time or Student's t-tests to analyzed changes between controls and treated at a single time point. Differences with p < 0.05 were considered statistically significant. Results: Exposure to 3DE resulted in reductions in progesterone and thyroid stimulation hormone and increases in follicle stimulating hormone and estradiol. After 1d of exposure to 3DE, transcripts for the immediate early gene Cfos were reduced and there was an increase catalase (Cat) and tumor necrosis factor a (Tnfa) expression in the olfactory bulb. After 30d of exposure, Cfos was still reduced, and interleukin 1β (Il1β) and vimentin (Vim) were increased. In the pituitary, there were no changes in transcript expression after 1 and 8d of exposure to 3DE. However, after 30d of exposure to 3DE, there was a reduction in Il1s and a slight reduction in estrogen receptor (Er) expression. Exposure to 3DE induced an increase in calcitonin-gene related peptide, acetylcholinesterase and Cat expression and reductions in glial fibrillary acetic protein (Gfap) and cyclic AMP response element binding protein (Creb) after 1d of exposure. Conclusions: Based on the results of this study, inhalation of 3DE generated by printing with polycarbonate stock induces effects on anterior pituitary hormones and gonadal steroids that are similar to the effects seen with exposure to BPA. Although additional data needs to be collected, changes in the hypothalamus and olfactory bulb suggest that inhalation of 3DE induces inflammation and oxidative stress. It also may interfere transcription of factors involved in one of the signaling pathways used by the estrogen receptor to regulate transcription (CREB-mediated). Description provided by NIOSH
• Subjects:
  • Endocrine System
  • Nervous System
  • Occupational Health
  • Polycarbonates
  • Printing, Three-Dimensional
  • Safety
• Keywords:
  • Additive manufacturing; Three dimensional printing; 3D printing; Inhalation; Laboratory animals; Endocrine function; Hormone activity
• Source:
  Toxicologist 2025 Mar; 204(S1):395
• ISSN:
  1096-6080
• Document Type:
  Text
• Genre:
  Abstract or Summary
• Place as Subject:
  Philadelphia Region OSHA ; West Virginia
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  HELD - Health Effects Laboratory Division
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  2 pdf pages
• Volume:
  204
• NIOSHTIC Number:
  nn:20071582
• CAS Registry Number:
  • Polycarbonates (CAS RN 25766-59-0)
• Federal Fiscal Year:
  2025
• NORA Priority Area:
  Manufacturing
• Peer Reviewed:
  False
• Download URL:
  https://stacks.cdc.gov/view/cdc/259357/cdc_259357_DS1.pdf
• File Type:
  [PDF - 279.26 KB]
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:997ef3e3e25ebd29640c23cefdb2bf65bcaa419e6ebb3a3bbcffa541bd06415b8ce1416f2af2d701fa06c52967150cf2f76db5fe5ca0af43eb04985452ea3735