Histological and histochemical characterization of the musk gland in forest musk deer (Moschus berezovskii): a preliminary study

Abstract

Musk is a biologically valuable secretion from the musk gland of male musk deer, with significant economic and medicinal importance. Due to severe decline and depletion of wild musk deer population, captive breeding of musk deer has become the primary approach for sustainable musk production. So far, the histological structure and secretion mechanism of the musk gland remain incompletely understood. In this study, we employed histological and immunohistochemical (IHC) techniques, along with three-dimensional (3D) tissue reconstruction, to systematically analyze the cellular composition and secretory functions of the musk gland in forest musk deer (Moschus berezovskii). Our results revealed that the musk gland was primarily composed of acinar structures containing two distinct glandular cell (GC) types based on the histological observation. IHC results showed type I glandular cells (GCIs) predominantly expressed GALNT7 while type II glandular cells (GCIIs) mainly expressed BMP6. The 3D reconstruction demonstrated structural heterogeneity along the gland's longitudinal axis, with the proportion of the acinar area varying between 40% and 65%. This is the first time that a detailed 3D view of musk gland in forest musk deer has been shown, which provides essential histological insights into musk gland function in this species. These preliminary observations may provide useful groundwork for future investigations into the regulatory mechanisms of musk secretion.

Figure 1.

Histological analysis of the musk gland in forest musk deer. a) The musk gland tissue originated from the male forest musk deer (M. berezovskii). b) Overview of the histological structure of the musk gland. c) Magnified view of acinar regions near the periphery of the musk gland tissue. d) Magnified view of the ductal area within the musk gland tissue. e) Magnified view of acinar regions in the central part of the musk gland tissue. f) Schematic diagram of the musk gland based on histological observations. GC, glandular cells; GCI, type I glandular cells; GCII, type II glandular cells; IC, interstitial cells; MC, myoepithelial cells; DEC, ductal epithelial cells.

Figure 2.

Immunohistochemical results of GALNT7 within the musk gland. a) Overview of immunohistochemical staining of GALNT7 in the musk gland. b) Immunostaining of GALNT7 in the acinar regions near the periphery of the musk gland tissue. c) Immunostaining of GALNT7 in the ductal area within the musk gland tissue. d) Immunostaining of GALNT7 in the acinar regions in the central part of the musk gland tissue. (e) Evaluation of GALNT7 immunostaining in the musk gland tissue. GC, glandular cells; GCI, type I glandular cells; GCII, type II glandular cells; IC, interstitial cells; MC, myoepithelial cells; DEC, ductal epithelial cells.

Figure 3.

Immunohistochemical results of BMP6 within the musk gland. a) Overview of immunohistochemical staining of BMP6 in the musk gland. b) Immunostaining of BMP6 in the acinar regions near the periphery of the musk gland tissue. c) Immunostaining of BMP6 in the ductal area within the musk gland tissue. d) Immunostaining of BMP6 in the acinar regions in the central part of the musk gland tissue. e) Evaluation of BMP6 immunostaining in the musk gland tissue. GC, glandular cells; GC I, type I glandular cells; GC II, type II glandular cells; IC, interstitial cells; MC, myoepithelial cells; DEC, ductal epithelial cells.

Figure 4.

a,b). Different magnification of 3D reconstruction with musk gland sections based on the H&E staining. c) The average ducts per section along with the z axis in the 3D view of musk gland. d) The proportion of acinar area per section along with the z axis in the 3D view of musk gland.