Effect of Acoustic Cavitation on Mouse Spermatogonial Stem Cells

Abstract

Objectives The mechanical index has long been one of the main criteria used to assess the safety limits for therapeutic medical applications. However, the safety of the mechanical index parameter is considered to be unknown in male fertility, which has a very significant role in vitro conditions. In this study, the effect of cavitation interactions due to mechanical index regions was evaluated on spermatogonial stem cells. Methods The acoustic pressure and mechanical index equations at the low intensities and the intended frequency were modeled and solved. The mechanical index average of 40 kHz frequency was selected as subthreshold, 0.70, and above the cavitation threshold. Neonatal spermatogonial stem cells were cultured. Spermatogonial stem cells are stimulated by low‐level ultrasound for 5 days and colonization and viability evaluated on the seventh day. Results Based on modeling, the mechanical index average was chosen as 0.40, 0.51, 0.75, and 0.89. The mechanical index of 0.40 and 0.89 resulted in a number of colonies of 93 ± 4 and 32 ± 4, respectively. An increase in colony diameter could be observed for a 0.40 mechanical index during all days of the culture that in the culture on the seventh day had the largest average colony diameter of 174.05 ± 1.22 μm in comparison with other groups (p < 0.05). The cell viability was not significantly different among the groups. Conclusion The results suggest that a low‐intensity ultrasound of 40 kHz with a 0.40 mechanical index can be effective in increasing the proliferation and colonization of spermatogonia in stem cells during culture.

Ultrasound Waves Effect on the Proliferation of Fibroblast Cells: Collagen Type I Expression

“…According to Rayleigh's equation, low-intensity and, low-frequency ultrasound parameters are obtained by acoustic pressure and MI modeling [17,18]. The Mechanical index higher and lower than the threshold of 0.20 were selected to examine the mechanical interaction, such as the micro-streaming, the acoustic cavitation, and collapse interaction, in vitro [16].…”

“…The analytical solution of acoustic pressure, ( ) P r′ , and the MI are obtained through an acoustic propagation equation. The conditions for solving the equation are given as follows [17,18]:…”

“…Considering the disc shape of the crystal, cylindrical coordinates are selected to solve the equation. According to Equation 3, Rayleigh integral pressure equation considers an acoustic transducer infinite element with a suitable size and less than the sound wavelength, acting as a point acoustic source [18]:…”

Recent advancement of sonogenetics: A promising noninvasive cellular manipulation by ultrasound

“…LIPUS has demonstrated an influential effect on the proliferation, differentiation, and migration of diverse stem/progenitor cells, including bone marrow mesenchymal stem cells, adipose tissue-derived stem cells, spermatogonial stem cells, neural stem cells, and hematopoietic stem cells. 159 , 160 , 161 , 162 , 163 , 164 , 165 , 166 , 167 Empirical evidence suggests that LIPUS stimulates responses in a variety of stem cell signaling pathways, namely YAP, RhoA/ROCK, Piezo, angiotensin, TGF-β1, MAPK, ERK, and protein kinase B (Akt). These responses to LIPUS vary according to the energy level applied and the origin of the cells.…”