Chronic THC Inhalation During Early Adulthood Exacerbates Ovariectomy-Induced Bone Loss in a Rat Model of Osteoporosis

Introduction: Osteoporosis is a debilitating bone disease that affects a large segment of the population. Currently, pharmacological treatment options for osteoporosis, including antiresorptive drugs and those that prevent bone loss, are limited. Multiple studies have shown that the endocannabinoid system and cannabis may play a significant role in bone remodeling. As both the use of cannabis and high-quality research on its effects continue to grow, novel medicinal uses of selected components, such as tetrahydrocannabinol (THC), are being investigated. The present study examined the potential effect of chronic THC inhalation during early adulthood on an ovariectomized rodent model of post-menopausal osteoporosis. Materials and Methods: Young (26-week-old) adult female rats received daily either THC or air inhalation for 8 weeks. The rats then underwent an ovariectomy (OVX) or sham surgery (Sx) when they were 34 weeks old. They were then euthanized 4 weeks post-OVX, and skeletal tissues were collected for analysis. Results: MicroCT analysis of femora showed that THC + OVX rats showed a significant decrease (45%) in trabecular bone volume compared to Air + Sham Sx rats. As expected, the Air + OVX rats also showed a 17% reduction in trabecular bone volume. Discussion: Overall, early adulthood THC exposure increased susceptibility to osteoporosis following ovariectomy-induced menopause. This suggests that THC exerts long-lasting effects on bone health, which may exacerbate post-menopausal bone loss.