Exploring of the Unpredicted Effects of Olfactory Network Injuries on Mammary Gland Degeneration: A Preliminary...

Purpose of the study: Hypofunctioning breasts are typically considered a dysfunction of higher brain centers that regulate hormonal feedback, and olfactory information has been proposed as a triggering factor for lactation in the maternal body. However, there are no substantive studies regarding whether olfaction disorders and/or loss of olfactory sense may result in breast gland atrophy by causing diminished olfactory stimulation. To fill this gap in the literature, we studied the histologic features of breast glands as a sample model in animals that had undergone an olfactory bulb lesion (OBL). Materials and methods: This study was conducted on 22 rats. Six, eight, and six of them were used as control, SHAM, and OBL groups, respectively. After 10 weeks, the animals were decapitated. Olfactory bulbs and breast glands were stained with Hematoxylin-eosin and tunnel dye. Specimens were analyzed stereologically to evaluate the loss in volume of the olfactory bulbs, total breast follicle volume (TBFV) and Meissner's corpuscles per cubic centimeter, and these two senior metrics were compared with each other statistically. Results: Olfactory bulb volume loss and breast gland atrophy were both detected in study group. Mean TBFV and OB volumes were measured as: (296 ± 89) × 10⁶ µm³/cm³ and 4.43 ± 0.98 mm³ in control (Group I); (264 ± 63) × 10⁶ µm³/cm³ and 3.86 ± 0.81 mm³ in SHAM (Group II) and (194 ± 52) × 10⁶ µm³/cm³ and 1.52 ± 0.36 mm³ in OBL group (Group III). It was noted that the TBFV was significantly diminished, with apoptotic degradation in the olfactory bulbs and breast glands of OBL-applied animals (p < 0.001). Conclusion: It seems that diminished milk secretion is attributable to the degradation of breast glands that results from olfaction loss in OBL animals.