Hippocampal Collagen as a Potential Target for Post-Surgical Treatment; Effects of Whole-Body Vibration and Exercise

Author(s): Noa Keijzer, Klaske Oberman, Tamás Oroszi, Csaba Nyakas, Eddy A Van der Zee, Regien G Schoemaker

Peripheral surgery may evoke neuroinflammation, associated with neuronal damage and consequently mental health problems. However, anti-inflammatory treatment showed limited therapeutic efficacy. Preservation of neuron integrity during neuroinflammation, by targeting their protective collagen sheet, may provide an alternative strategy. Whole-body vibration (WBV) and exercise combine anti-inflammatory and collagen-increasing effects in the periphery. The present study aimed to explore the therapeutic efficacy of postoperative WBV and exercise on hippocampal neuroinflammation and collagen expression.
Three months old male Wistar rats underwent abdominal surgery. Starting from one day after surgery, rats were submitted to WBV (10 min, once or twice daily), running exercise (30 min, daily), or pseudo WBV/exercise, for two weeks. Rats were sacrificed and brain tissue was collected and processed for (immuno) histochemistry. Hippocampal microglia activity, total collagen content, and expression of fibrillar and nonfibrillar collagen subtypes were analysed.
Surgery increased microglia activity in the CA1 area, which was only partly reversed by the interventions. Surgery reduced total collagen expression in the CA1 area, which was restored by both WBV and exercise. The surgery-induced decrease in collagen III expression in the CA1 area was not affected by WBV or exercise. However, surgery increased collagen III in the CA3 and DG, which was (partly) reversed by exercise, and to a lower extent WBV. Collagen IV expression was not altered by surgery, but increased by WBV.
Both WBV and exercise restored the surgery-induced declined collagen expression, while partly reversing microglia activation in the CA1 area. Effects on collagen appeared subtype- and region-specific, with overall similar effects of WBV and exercise. Nevertheless, the neuroprotective potential of postoperatively altered brain collagen needs further investigation.